Another way

RCA serres you through Eleetrouies

HI -FI DESIGNERS i 9 "JAM SESSIONS" ...and they "dig" RCA TUBES "the most "!

One designer "blows a horn" for one tube type. dissipation capabilities. And high -mu twin triode Another "beats the drum" for a 2nd. Everybody may RCA -7025 is tops in pre -amplifier stages when low "sound off" -but when they " ", designers noise and low hum are a "must ". For versatility, agree that RCA Hi -Fi Tubes...7027 -A, 6973, 7025 check RCA -7199, a triode -pentode that features low noise in tone -control amplifier, phase - and 7199... are "the most" ! hum and low Want big power? A pair of RCA -7027 -A's in Class splitter, and high -gain voltage -amplifier circuits. AB1 can deliver up to 76 watts. (Four in twin, push - So "get with" RCA Tubes for your hi -fi designs. pull Class AB1 circuits are superb for stereo, too!) Your RCA Representative can give you the facts. Designing a more compact package, say, 20 watts For data sheets, write RCA Commercial Engineer- each stereo output stage or 40 watts monophonic? ing, Section II-91 -DE, Harrison, N. J. Look into RCA -6973, a small tube with big plate

FIELD OFFICES Visit the RCA Booth at WESCON! EAST: 744 Broad Street, Newark 2, N. J. HUmboldt 5 -3900 MIDWEST: OF AMERICA Suite 1154, Merchandise Mart Plaza RADIO CORPORATION Chicago 54, Illinois, WHitehall 4 -2900 Electron Tube Division Harrison, N. J. WEST: e 6355 E. Washington Blvd. RCA tubes for also available from your local Authorized RCA Distributor Los Angeles 22, Cal., RAymond 3 -8361 THE BRITISH INDUSTRIES

1C

1 ENpaSED \ n g't i /...just one reason -per -product why you should consider BIC components for your stereo requirements.

The World's Finest Stereo Record Players Warm, universal endorsement by eminently satisfied users and dis- tributors everywhere, as the world's best automatic changers, manual players, and turntables, in every model, in every price range.

Stereo -mono Amplifiers Incomparable quality in sound and construction (yet, with startling simplicity) ...quality which holds harmonic distortion to an infinites- imal 1 /10 of 1% at lull rated power, and permits an unconditional 5 year guarantee...the only one in the industry!

Vharfedale

Loudspeakers and Systems The rich, full range, yet non-stri- dent sound developed by England's renowned G. A. Briggs...the latest example of which is in the new ultra- compact (10" by IIW by 24 ") Model WS /2 lull -range system ... the sound of a BIG Wharfedale system. the size ideal for stereo. Speaker Enclosures A complete, restyled line of the original and patented high -per- formance, small -space speaker en- closures which are now a must for stereo. Although R -J is the most emulated enclosure on the market in size and shape... no one has been Jure to copy the patented R -J per- formance principle.

River Edge

Customized Cabinets and Do -It- Yourself Kits The Series 100 modular kits are as flexible for stereo as for mono sys- tems...and most important. they are built of Birch hardwood, to take a quality living -room finish. And...this one series is a complete kit line in itself.

5-Core Solder Pioneering solder advancements. Multieure. the world's finest solder ...now offers the new copper -loaded SAVBIT Alloy which makes cop- per tips last 10 times longer. Only Multieure. in regular and SAVBIT Alloys, contains extra- active, non. corrosive ERSIN flux.

Genalex

Audio Tubes Origination and promotion of the famous KT66's and KT88's, ack- nowledged throughout the world as the finest tet rodes ever made? These Genalex tubes are selected and used by the leading manufacturers of quality audio power amplifiers for the highest possible performance with the lowest distortion.

14'e hate prepared a . ut ( potato, Gtdde, n critic the I (11C product ht.., and w e sill he hnpp to tend than to int . Please wrote, speeding the BIC products slid, uuerest ou. Address Dept. A V- /v BRITISH INDUSTRIES CORPORATION PORT WASHINGTON, N. Y. , 1959 VOL. 43, No. 8

Successor to RADIO, Est. 1917. Discover for yourself why Sherwood is the most honored line of high fidel- ity components in the field. Sherwood Tuners (the first ever to achieve sensi- tivity under 0.95 microvolts) feature: Inter -Channel Hush, a noise muting system which makes FM tuning easier than ever FM Multiplex Output "Feather -Ray" Tuning Eye Automatic Frequency Control Flywheel Tuning. AU D Combine these tuners with either of Io Sherwood's "mated" ENGINEERING MUSIC SOUND REPRODUCTION stereo amplifier choices; 20 +20 watts or 36+36 C. G. McProud, Editor and Publisher watts. And only Sherwood offers all these features: Single /Dual Bass & Henry A. Schober, Business Manager Treble Controls Mid -Range Presence Harrie K. Richardson, Associate Editor Rise Stereo -Mono Function Indicator Linda Sueskind, Assistant Editor Lights Phase -Reverse Switch Damping Factor selection. Sherwood Janet M. Durgin, Production Manager also offers either 36 or 60 watt mon- Edgar E. Newman, Circulation Director aural amplifiers, FM Multiplex Adapters and a complete decorator- styledline of cabinetry and 3 -way speaker systems - The Finest in High Fidelity. Sherwood Electronic Laboratories, Inc., 4300 N. Sanford L. Cahn, Advertising Director California Avenue, Chicago 18, Illinois. Midwest Representative - W. A. Cook and Associates Model S -5000. 20 + 20W Slew Dual Amplifier -5189.50 161 East Grand Ave., Chicago 11,111. West Coast Representative - 0 0 ©6) 450: lames C. Galloway 6535 Wilshire Boulevard, Los Angeles 48, Cali!. Model S -3000 U. FM Tuner -$105.50 CONTENTS

Audioclinic- Joseph Giovanelli 2 Model 5.4400. Stereo Peins,. f 36W Amp. - $159.50 Letters 6 Audio ETC -Edward Tainan Canby 12 C3.C, ©6)0.x. Editor's Review 18 Model S.200013, FM -AM Tuner -$145.50 Transistor Music System Using Direct Coupling- Richard S. Burwen 21 Hi -Fi Speaker Enclosure Damping Materials -James A. Huff, Jr. 26 ©- Tape Guide -What to Look for in a Tape Recorder-Herman Burstein 32 Model 5.1000 a, 36W Amplifier- 5109 50 Variable Electronic Crossover and Biamplifier- George C. Kane 42 only for those who want the ultimate: Hi -Fi for Lo -Do-S. G. Lucas 50 Errors and Mistakes of Engineers-A lbert Woodruff Gray 56 Product Preview 67 STEREO Jazz and All That-Charles A. Robertson SG Record Revue-Edward Tatnall Canby 92 Book Review The Audio Cyclopedia 99

About Music- Harold Lawrence 100 Coming Hi Fi Shows 101 Advertising Index 114

COVER PHOTO: Custom installation in North Stamford, Connecticut, designed F. Barton, by C. with cabinetry by Russ Lang Corp., Bridgeport Conn. Unit is 14 feet long ill three sections; the record cabinet is two feet long and features an interior light. For further data and a close -up picture of control panel, record changer compartment, and ventilating ducts, turn to page 104. Photos by Frederick Schulze.

AUDIO (title registered U. S. Pat. OP.) Is published monthly by Radio Magazines, Inc, Henry A. Schober, C. G. 3IcProud, Secretary. Executive President; and Editorial Omees, 204 Front St., Mineola. N. Y. Subscription Possessions, canada and Mexico, $4.00 rates -U. S. for one year, $7.00 for two years, all other countries. $5.00 per year. copies 504. Printed In U.S.A. at Lancaster, P.. Single All rights reserved. Entire contents copyrighted 1959 by Radio Magazines. Inc. Entered as Second Class Matter February 9. 1950 at the Post Office. Lancaster. Pa. under the act of March 3, 1879. RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y. Postmaster: Send Form 3579 to AUDIO, P. O. Box 629, Mineola, N. Y. For complete technical details write Dept. -8. AUDIO AUGUST, 1959 1 AUDIOCLINIC ?? JOSEPH GIOVANELLI' Power and Voltage Considerations that same direction, and the two arrive at that .maximum at the same instant. When Q. The specifications of my Dynakit am- this same current is applied across the plifier indicate that 1.6 volts input are re- terminals of an inductance, the situation WAYS quired for 60 watts output. It therefore is quite different. This can be made clear seems like an easy matter to measure the by considering what happens when d.c. is To ENJoY voltage at the output terminals when the applied to the inductance. When the volt- amplifier was fed by a 1.6 -volt signal. This age is applied, there is a magnetic field set E voltage was found to be approximately 40 up around the inductance. This field cuts volts. Since my speaker cannot handle 60 the turns of the inductance, causing a watts, this was a no -load measurement. I second voltage to be generated within the RoBERTS could not experiment with a lower input coil. By the rules of magnetic theory we because I did not know the corresponding know that when this happens, the direction output wattage. It would seem that the of this newly created back voltage is op- %;; !.+ Ohm's law a.c. formulas should be applica- posite to that of the originally applied volt- ble to this problem. Please tell me a simple age. This tends to oppose the flow of cur- way to determine wattage from voltage. rent. Soon the magnetic field reaches a What is the relation between input voltage maximum intensity because we are feeding and watts output! Tell me how to deter- d.c. to the coil, and this will ultimately mine the phase angle, for I understand cause the current to stabilize. From that that this may have some bearing upon the time on, the inductance behaves as though problem. Richard Meyer, East Lansing, it were resistive. When the inductance is Mich. fed from a.c., however, the voltage and A. Power is a measure of the work being current can never catch up with each other, done. Now, when you measured the ampli- for, as the current tries to do so, the cycle fier's voltage output under no-load condi- reverses and the whole thing starts all tions, you arrived at a situation wherein over again. We say that, for an inductance, you had voltage developed, but that voltage the voltage leads the current by 90 deg. was doing no work of any kind because it "How," you wonder "did the degrees enter was fed into nothing. In order to determine into thisl" A.c. is cyclical in character. A anything about the wattage of your ampli- cycle starts off at zero, rises to a maxi- fier, the signal must be fed into something mum in one direction, falls back to zero, which would be indicative of the conditions and rises to a maximum of opposite po- under which the amplifier normally works. larity exactly equal in magnitude to that As you said,' your speaker system cannot of the first rise, and therm it returns to zero HOW TAPE take all the power which can be provided again. It next starts all over again, rising EQUIPMENT SERVES by the Dynakit, and in fact, neither could to a maximum in the first direction. (This upon the assumption that the wave MANY AUDIO NEEDS your ears. What is needed, then, is a device is based which will act as much like a speaker as described is a pure sine wave.) The whole 22 are discussed in new possible, but will make no sound. What is thing goes round and round. A circle could, ac- Roberts boòk/et doue in practice is to take a resistor equal therefore, be drawn to represent this to the impedance of the amplifier tap se- tion. If it is considered that this cycle is Roberts Electronics Inc. has prepared direction, booklet to demonstrate lected for the experiment. This resistor traveling in a counterclockwise this 20 page inductance is wide versatility and high quality re- should be of as high a wattage rating as the voltage will, when a pure the the production of monaural and stereo tape possible since your amplifier delivers 60 the only element involved, be 90 deg. to equipment. Eight ways to record live or watts. Don't be alarmed if you do not have left. Unfortunatelly, we never get a pure from broadcasts and to dub or copy from one that can handle that much power; a 10- inductance: there is always some resistance disks and tapes are discussed, including the watt resistor can handle as much as 80 present. This reduces the leading or lag- correct way to tape stereo broadcasts. phase watts for a short while, probably long ging effect, or, in other words, the Also included in this informative booklet enough for you to compute your data. angle. Just how much this is reduced will are ten methods to play back through Under these conditions the transformer is depend upon the amount of inductance and The high level and low level external ampli- loaded, thereby reducing the back voltage upon the amount of resistance present. fier /speakers in both monaural and stereo. it produces. This, in turn, indicates that the whole thing can be considered as a right are given for the use of tape Suggestions voltage at the output of the secondary will triangle whose hypotenuse represents the equipment to "dub in" vocal or instrumen- resist- be less than the unloaded value; measure- combined effects of inductance and tal accompaniment by mixing and multiple all mathematical work will recording. ment will bear this out. ance. Naturally, between a speaker proceed vectorially since the hypotenuse The booklet treats with the general use and When the impedance the the square root of the sum of care of tape equipment and instructions for and its driving amplifier is matched, represents the other two sides of the tape splicing, microphone placement and re- system is said to be resistive, and for this the squares of is basic to Plane cording procedure. A complete index and bib- reason, the phase angle need not be con- triangle. This concept and hence liography are included. sidered. Actually, the phase angle may Geometry and Trigonometry, further here. Before you buy a tape recorder, you will want to enter into the picture somewhat since the will not be explained opposite read this valuable booklet, "22 Ways to Enjoy the match is not perfect, and the speaker be- Capacitors behave in a manner in a Roberts." For your copy, just fill out and mail haves like an inductance or capacitance at to that of inductances. The current the coupon below. different parts of the spectrum. capacitor leads the voltage by 90 deg. Ca- also and there In explaining just what is meant by the pacitors contain resistance as a pure capacitance. ROBERTS ELECTRONICS INC. phase angle a brief discussion of alternat- is no such thing N. the behavior of a ca- 1045 Sycamore. Los Angeles 38, Calif. Dept. D ing current is needed. When a.c. flows The reasons for Please send me a copy of "22 Ways to Enjoy the best explained by considering through a resistance, the voltage and cur- pacitor are Roberts. "' when the capacitor is con- rent are in phase, which means that as the what happens NAME. Since the plates are neutral, voltage rises to a maximum in one direc- nected to d.c. to crowd on to one plate ADDRESS tion, the current rises to a maximum in the electrons rush - moment the circuit is closed. This at the CITY . ZONE STATE so great at the first instant that Enclose lac (stamps, cash) for handling & postage 3420 Newkirk Ave., Brooklyn 3, N. 1'. action is

AUDIO 11 AUGUST, 1959 2 "Our All -New eu: VR22 Stereo Cartridge provides unsurpassed performance in a Garrard Changer." In thanking Mr. Welsh for these personal comments, we would like to point out that hundreds of thousands of GE Monaural cartridges played a vital part in making high fidelity history during the past decade. Particularly significant is the fact that more GE cartridges were used with Garrard changers in fine component systems, than in all

other changers and turntables combined ! Now, GE owners, and all others converting to stereo, will be delighted to know that a Garrard changer, such as the incomparable RC88, guarantees the superlative performance that has been built into the new GE stereo cartridges.

"Unsurpassed Stereo Results with the VR22 in Garrard Changers," says Mr. S. J. Welsh, Manager- Marketing, High Fidelity Components, General Electric Company

"The new GE The same Stereo Classic cartridge Model VR22 has a reasons why Garrard changers perform so 'floating armature' design for increased compliance magnificently with GE cartridges have also made and equally them reduced record wear, and a flat frequency response popular with all other manufacturers of fine Stereo of 20- 20,000 cycles. To retain this performance, it is cartridges -, Electro- Voice, Pickering, Fairchild, etc. necessary that a tone arm track freely and with Vibration -free turntable. recommended the light pressure. The motor must also have a Vertical and lateral rumble completely inaudible. Wow very low rumble content. and flutter far below exacting "broadcast tolerance" standards. Exclusive Aluminum tone arm precision- "Therefore, we are gratified to mounted at report the excellent engineering works for optimum tracking angle, perfect sound results we found when testing with Garrard changers. reproduction. All of the rigid laboratory standards built into our Unrestricted choice of stereo cartridges -any of them will new cartridge were maintained. The result was excellent track at the manufacturer's lightest specified weight. stereophonic music reproduction." Record handling gentler than the surest human hand. The important convenience of manual play plus completely automatic operation without compromise in performance. These are the FACTS, no one can deny them with authority- and they are backed by the 36 years of experience that have created Garrard's unique reputation for unsurpassed quality.

Send for free Garrard Comporaror Guide For the best in Stereo... Insist on a -

Garrárd édit ity system: tie itnslñairidand wired for- Stereo -and14anaur#1 k, ee :sew 'actaia í Dow. y etW Owe T" c,lptl>n Tre'Me Temt,p, f!50 859.50 :N7 íI1:30 \\ Wool I . ís9.00 -Df1 !' O 16R.Ofl t- GARRARD SALES CORPORATION, Division of British Industries Corporation, PORT WASNINGTOYt,N. Y. Conadion iiiniiiiliii lo Che, W, Ponton, Ltd., 66 Rocino Rood, Ro.dale, Ont. - t , Territories other than U.S.A. and Ca ode to. Oo,,ord Enoinnrina 6 MI5. Co.. ltd., Swindon, Wills., Enalaa : d.c. is applied that the d.c. supply is Tung -Sol audio tubes momentarily short -circuited. The voltage, therefore, drops almost to zero. It does not dynamically balanced take long before the plate becomes fully charged, or "crowded" with electrons. It re- and twin -packed quires more and more time for an electron in matched pairs to find room. This means that the d.c. supply is gradually unloaded. There will by the manufacturer finally come a time when there is no more room for further electrons to gather, and from any of the dealers in the supply will then run at its normal op- erating voltage. No more current is being your city who are listed. taken from it. When a.c. is applied to the capacitor, the circuit can never arrive at the volt- a stage of equilibrium. Note that RADIO SHACK CORPORATION age lagged the current in this illustration. 730 Commonwealth Ave. to know about the Boston 17, Mass. Lastly, you wished RE 4.1000 relationship of the variations in output -- Branches - voltage of an amplifier to the power de- 167 Washington St. livered to the load. If the input of an am- Boston, Mass. 230 Crown St. plifier requires two volts for a power output New Haven, Conn. of 20 watts, the power output will be re- is CATANIA SOUND duced to 5 watts if the input voltage 1541 Fourth St. reduced to 1 volt. That is, the power varies San Rafael, Calif. However, the as the square of the voltage. KIERULFF SOUND CORP. input and output voltages will vary di- 820 W. Olympic Blvd. voltage to Los Angeles 15, Calif. rectly. If I reduce the signal 1, RI 7-0271 the output voltage will fall to % of what - Branches -- it had been before the reduction in input 18841 Ventura Blvd. voltage had been made. Tarzana, Calif. 6035 Magnolia The next logical question is: "Why does Riverside, Calif. the power vary as the square of the volt - 12024 Wilshire Blvd. aget" Power is equal to voltage times cur- W. Los Angeles, Calif. rent, E x I. It does not matter that the WRIGHT'S HOUSE OF HI FI since we do know the 5140 El Cajon Blvd. current is not known San Diego 15, Calif. resistance into which the power is being the current is equal to D'ERRICO FIDELITY RADIO fed. We know that 3006 Wilshire Blvd. 5881 For service in 6550 For service in the voltage divided by the resistance, E /R. Santa Monica, Calif. EX 4.6209 amplifiers of up to 50 amplifiers and commer- Thus wattage, W, equals E x E /E, or E' /R. watts. cial audio equipment of That is how the exponential business creeps AUDIO WORKSHOP INC. up to 100 watts. in to destroy what would have been a sim- 1 So. Main St. West Hartford, Conn. ple arithmetic problem. Assume an amplifier to which is con- GOLDEN EAR INC. close to 610 S. 3rd you can come as nected a 16 -ohm resistor between the 16- Louisville 3, Ky. N oNowfaultless sound reproduc- ohm tap and common. Assume a signal of -- Branches -- as the design and circuitry As- RI 3 -1784 tion one volt is applied to the input grid. Ind. of your hi -fi equipment will read across the 16. West Lafayette, sume that the voltage ME 4 -8761 permit. Tung-Sol 5881 and 6550 ohm resistor under these signal conditions Indianapolis, Ind. beam -power amplifier tubes are 20 volts. What power is the amplifier Washington St. is Ind. dynamically balanced and fac- supplying to the resistor? Martinsville, tory- matched to very tight per- Solution: in our derived formula, W RADIO DOCTORS HI FI to help you 811 W. Springfield Ave. formance limits E' /R, we can substitute our two knowns Champaign, Ill. achieve lowest distortion at all as follows: E = 20 volts, B= 16 ohms. Fleetwood 2 -6464 levels. rewritten to volume Therefore, the formulas can be AUDIO CENTER, INC. Use of Tung -Sol 5881 and read W = 20r /16, or 400/16, which is 25 17001 Kercheval Ave. 6550 tubes has long been asso- watts. Grosse Points 30, Mich. ciated with amplifiers of the If the input voltage is reduced to 0.5 AUDIO KING CO. These tubes the 16 -ohm 913 West Lake St. very finest design. volt, the voltage as read across Minneapolis 7, Minn. have always been produced to resistor will be 10 volts. By applying our tolerances with we see the power supplied to DAVID BEATTY STEREO HI -FI closest possible formula, that 1616 Westport Road cathode current ranges held to the resistor under these conditions is 6.25 Kansas City 11, Mo. absolute minimum. rather than the 12.5 watts we might an watts, ADSON RADIO ti ELECTRONICS CO. Now, in twin -packed pairs, have expected. 189 Greenwich St. they assure the hi -fi enthusiast The following information does not bear New York 7, N. Y. and the commercial sound en- directly upon the foregoing problem, but LYRIC HI -FI, INC. in some respects. Suppose it is 1190 Lexington Ave. gineer of replacement tubes that it is similar New York 28, N. Y. will provide new standards of necessary to determine the power being supplied to a resistance when only the WRYE COMPANY, LTD. performance -a feature of 2410 W. Alabama special importance with the values of the current and of the resistance Houston 6, Texas newest amplifiers and loud- are known. Voltage can be readily obtained JA 6-3033 by resistance, I x R. speakers, particularly binaural by multiplying current THE RADIO HI -FI SHOP The result can be multiplied by the current 603 Broadway North sound equipment. See your Seattle 2, Washington parts supplier. and the resulting answer will be the desired power. These operations, however, can be HOUSE OF HI- FIDELITY Electric Inc., Sales, Inc. Tung -Sol as follows: The voltage is equal 20th Century Newark 4, New Jersey. combined W. 1021 First Ave. to the current times the resistance, E = IR. Spokane, Washington for power is volt- The fundamental formula DOW RADIÒ, INC. age times current, or EI. Since E is equal 1759 E. Colorado St. TUNG-SOL to IR, power is equal to I x IR, or PR. Æ Pasadena, California AUDIO AUGUST, 1959 4 6. the best of 110J .. A NEW compenr!irfm AUDIO knowledge

SPECIAL

PRE - PUBLICATION OFFER!

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ohtt of AUDIO FOR YOUR CONVENIENCE... been selected as Publication special distributors major cities You torsrsin have of the dealersOffer. this SpecialPecial page. city copy If there is your who are listed from any use the dealer on the di handy no listed for adjoining pre-pre-publication your city, cou Pon to order your you price from may RADIO MAGAZINES,UINCPectal

"the best of AUDIO" Volume I features:

The AUDIO Clinic by Joseph Giovanelli ...noted audio engineer, authority and tech- THIS OFFER 0000 nical writer, and fidelity answer -man. Here is a compilation of ONLY UNTIL his best work ... the most important issues and facts, the answers to some of the AUGUST 25. 1959 most perplexing high fidelity problems covering all phases of AUDIO technicana from microphones to stereo. RADIO EQUIPMENT PROFILES edited by C. G. McProud ... Publisher and Editor of AUDIO, Magazines, Inc., the original magazine about high fidelity. Here, in Mr. McProud's matter-of -fact Dept. 98 style of writing is a profile analysis of high fidelity components in action. The Post Office Box 629 EQUIPMENT PROFILE is definitely not a test, but rather a factual and thorough Mineola, New York report of what makes a component tick ... what it does... how it does it ... a valuable reference for the high fidelity shopper. . Enclosed is my remittance or $1.50 . Please send my copy of the of

promptly by return mailbest, POSTPAIDAUDIO . SPECIAL PRE -PUBLICATION OFFER ...$1.50! '". Name To be published July 15th at $2.00, the 1st Volume of "the best of AUDIO" . Address is scheduled for shipment to bookstores September 1st, 1959... order your ./ volume now and receive shipment at least one full month early City Zone State and, SAVE 25 %! Remit only money order or check. No cash or stamps please. for less work and more play LETTERS Stereo Recording in Education results, high costs, lack of time to experi- GET THE TURNTABLE ment, and so on. we had more informa- SIR: If tion available as a sort of criteria for such For several years I have been studying, applications perhaps satisfying results THAT CHANGES RECORDS! including school committee work, some of could be obtained; at least people would be the possibilities for more effective use of better apprised of the requirements and teacher competencies in our schools and correct procedures. adult education. One of these involves the The school publication in the audio visual use of stereo tape recording for improving fields do not seem to do anything about music programs and in the language teach- this situation. Perhaps it takes an appreci- ing laboratory in elementary and high ably higher technical level of writing and schools. The latter art is fairly well de- experience to get the idea over and to be veloped and accepted at College levels, but specific in enough areas, or to take such a not in the lower levels. Perhaps some of big subject and bring it into the language your readers may have developed some in- of this type of prospective user of stereo formation that would be helpful. recording equipment. In my search I Most of the experiments (including two reached an audio engineer in Hollywood by one district by calling in professional who had developed such instructions and recorders) on the use of two- channel re- would provide an article or manual for $50 MIRACORD XS-200 corders in music programs have been con- -too much for people in school activities. sidered by the school people as rather com- At any rate here is the problem. Perhaps plete failures (in spite of their recognition some of your readers will be able to help No turntable and no record player, of the commercial acceptance of stereo re- or to provide some references. in the history of high fidelity, gives producers in consumer products area, LLOYD P. MORRIS, you more quality and more features though some think it is a fad). the famous MIRACORD 2947 N. 78th Court, than XS -200! Admitting that stereo-binaural pick -up heavyweight, professional -type turn- Elmwood Park, table -and a fully -automatic changer! and recording is difficult does not justify Chicago 35, Ill. plays both stereo and monophonic! our continued neglect to provide some sort push -button controlled throughout! of guides, suggestions, cautions, and more (And a serious problem it is, too. Unfortu- Magic Wand spindles eliminate specific considerations of the art. I have nately, most stereo recording techniques are pusher platforms and stabilizing arms! written several recorder manufacturers regarded as at least "confidential" if not intermixes 10" and 12 "; plays all about this problem, and I have contacted "top secret," and it is rare that we are per- 4 speeds; has a 4 -pole motor! owners of this equipment. The story gener- mitted to reproduce a photo of an actual even as a turntable it shuts off is is not good automatically when record is ally that the equipment recording session with the microphones all finished and tone arm returns to enough for the job, and I think there will in place. However, we do not consider $50 rest position. he a reaction against stereo recorder units too high if the manual were written to your -yet it costs omit $6 a net if this situation is not changed so that order -in fact, it is so low that it probably these owners can get better results. I feel wouldn't be worth even that amount. We that the trouble is not with recorders, but have never encountered anyone with profes- with the pick -up and recording techniques. sional experience who was willing to give It seems that the manufacturers have not out any information. It would be desirable provided good application instructions for for all the tape and recorder manufacturers the most effective stereo pick -up and re- collectively to commission someone to write cording results, with some discussions of such a book -and we hope they do, we'd some of the "tricks" of the trade on how like to publish it. Here's hoping some reader to make the final results more desirable and in your vicinity may volunteer to help you how to better adapt the system to the out, and possibly to annotate his findings particular musical demonstrations. The user for later publication for everyone inter- needs to know how to plan for different ested. ED.) applications of strings, banda, large and small groups, music rooms, solo, choral, and More Desirable Subjects STEREOTWIN 200 other types of work. All of this is a part of the over -all use of and satisfaction from SIR: this kind of equipment by the more dis- May I suggest a couple of topics that I criminating users and for educational ap- have not seen covered anywhere in more the stereo cartridge that plications. than incidental fashion that should be Perhaps this sort of thing has been done. useful to many readers? ELIMINATES HUM! If so, I have not found it. I know of several How about a really thorough article by others in school work and citizen applica- a competent authority on the use of voltage uses STEREOTWIN is the perfect magnetic tions who have also looked for this kind of regulator tubes, including possible and hi -fi cartridge for stereo and mon- information; some have relegated the applications, precautions and things to aural! It fits all record changers and equipment to storage and relatively incon- avoid, and possible troubles and what to do standard tone arms. And thanks to sequential use, somewhat discouraged that about them. The same suggestions go for special construction and MuMetal they spent the money in the first place, the design and use of regulated power sup- shielding, it eliminates hum! Instant (not talking about disc equipment). If this plies employing vacuum tubes with control stylus replacement, too. kind of information is available, perhaps grids. Design of such circuits should not be not, beyond the capabilities of the average tech- NOW $4450 audiophile net you can inform me, with references. If perhaps you could get some articles in your nician or advanced amateur. magazine on the more effective use of stereo I would like to know of any books that FAR AHEAD) THE FINEST BY FAR tape recorders. contain this information. The best I have Available at selected dealers. As a school board member I feel that we been able to find on VR tubes so far has could improve our musical programs by been from the Heathkit catalogues before For Free catalogue. please Irrite Dept. A AUDIOGERSH using stereo recorders. In addition I think they started omitting values from the CORP. that such tapes could be used in demon- schematics. 514 Broadway, New York 12, N.Y. strations to further our already meagre KEITH CONRAD, WORTH 6 -0800 public relations programs. Such proposals 816 W. Belle Plaine Ave., generally meet with the problems of poor Chicago 13, Ill.

6 AUDIO AUGUST, 1959 J

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AUDIO AUGUST, 1959 7 ANOTHER FIRST FOR HEATHKIT amplifier power rating standards

Hcathkit is accustomed to pioneering ... to leading the way. We led the way into the kit field of electronic equipment. Now, we arc leading the way to audio amplifier power rating standards . . . standards clearly defined to assure you of Heathkit quality . . . to enable you to compare before you buy. The Heathkit amplifier standards have been established upon these following beliefs after reviewing over one hundred published treatises on the subject: WE BELIEVE any amplifier should be rated for its intended

use . . . PROFESSIONAL amplifiers must be so nearly perfect that no audible change occurs in the program material. HIGH FIDELITY amplifiers must be almost as perfect, almost 1. Maximum power at which total harmonic distortion (THD) as efficient. does not exceed 1.0% at 1000 CPS. UTILITY amplifiers can be less perfect and still fulfill their 2. Maximum power at which total harmonic distortion (THD) practical job. does not exceed 3.0% at 60 CPS. WE BELIEVE the rated power of an amplifier in any of the 3. Maximum power at which total harmonic distortion (THD) above "use" categories should be that power which satisfies all does not exceed 3.0% at 7000 CPS. requirements in that category. 4. Maximum power at which response does not deviate by more Each of the three "use" categories we have chosen has require- than ±1 db between 60 and 7000 CPS. ments which can be translated into performance specifications with 5. Maximum equivalent single -frequency power at which in- rather definite limits ... limits established by recognized author- termodulation distortion does not exceed 3.0% (60 and ities. The Heath requirements and their limits for each of the 6000 CPS, 4:1). categories are as follows: We at the Heath Company are now rating all our amplifiers to PROFESSIONAL RATING these standards. To show you just how this rating system works, The professional power rating shall be that power which satisfies let's look at the Heathkit EA -3 amplifier: the following five tests: As a professional amplifier - does not exceed 0.3% at 1. Maximum power at which total harmonic distortion (THD) 1. Maximum Power at which T.H.D. does not exceed 0.3% at 1000 CPS. 1000 CPS: 15.1 watts does not exceed 2.0% at 2. Maximum power at which total harmonic distortion (THD) 2. Maximum Power at which T.H.D. does not exceed 2.0% at 20 CPS. 20 CPS: 13.9 watts which does not exceed 2.0% at 3. Maximum power at which total harmonic distortion (THD) 3. Maximum Power at T.H.D. does not exceed 2.0% at 20,000 CPS. 20,000 CPS: 15.3 watts does not deviate more 4. Maximum power at which response does not deviate by more 4. Maximum power at which response than ±1 db between 20 and 20,000 CPS. than ±1 db between 20 and 20,000 CPS: 17.6 watts. single -frequency power at which in- ' 5. Maximum equivalent single -frequency power at which 5. Maximum equivalent intermodulation distortion does not exceed 1.0% (60 and termodulation distortion (60 and 6000 CPS, 4:1) does not 6000 CPS, 4:1). exceed 1%: 18.0 watts. Taking that power which satisfies all five tests, we could rate the HIGH FIDELITY RATING EA -3 for professional use, at 13.9 watts. Its advertised professional fidelity power rating shall be that power which satisfies The high rating is a conservative 12 watts. the following five tests: A of the chart below shows why the EA -3 is rated at 14 (THD) review 1. Maximum power at which total harmonic distortion watts for high fidelity applications, and 16 watts as a utility amplifier. does not exceed 0.7% at 1000 CPS. that our specifications are set at rated power for one or (THD) Notice 2. Maximum power at which total harmonic distortion more classifications (when our customers need an amplifier for a does not exceed 2.0% at 30 CPS. particular use, we believe thay want it to deliver its rated power (THD) 3. Maximum power at which total harmonic distortion under those particular conditions). Observe that our distortion does not exceed 2.0% at 15,000 CPS. figures are specified at the limits of the amplifier frequency range response does not deviate by more 4. Maximum power at which as well as at the traditional 1000 CPS (the common practice of than ±1 db between 30 and 15,000 CPS. rating distortion only at 1000 CPS does not tell you what happens at which in- 5. Maximum equivalent single -frequency power throughout the full range of the amplifier). 2.0% (60 and termodulation distortion does not exceed As an example of how these standards work on several corn - 6000 CPS, 4:1). petitive amplifiers, we have prepared the following chart. Notice UTILITY RATING that if the amplifiers did not meet standards at rated output power, The utility power rating shall be that power which satisfies the we have determined the power output where they do meet the following five tests: standards set up under the three categories.

AMPLIFIER COMPARISON CHART Maximum Power Output Satisfying: Amplifier Heath Standard Rating Description Power Power Rating Power Rating Power Rating Power Rating Power Rating Stds. at Test 4 Stds._ at Test 5 Stds. _and Price Classification (watts) at Test 1 Stds. al Test 2 Stds. at Test 3 watts Kit "A" Professional Disqualified 8.4 watts 0.02 watts 0.65 watts Disqualified 3.9 "12 w. HI FI" High Fidelity Disqualified 9.1 1.3 1.67 Disqualified 5.9 12.3 watts 11.6 $23.90 Utility 8.6 watts 9.8 8.9 8.6 Assembled Amp. Professional 0.3 4.7 0.3 4.8 1.2 4.0 8.2 "B" "14 w. HI FI" High Fidelity 1.1 12.1 1.1 5.7 5.3 15.8 13.9 $39.50 Utility 7.8 13.2 7.8 12.9 6.5 Kit "C" Professional 3.6. 11.0 3.6 7.5 7.5 13.4 14.3 "12 w. HI Fl" High Fidelity 8.0 11.8 8.0 11.2 11.9 15.0 14.9 $34.95 Utility 11.9 12.0 12.0 Professional 3.8 13.2 3.8 14.5 12.0 14.6 25, Assembled Amp. 16.3 Benton Harbor " D" "15 w. HI FI" High Fidelity 10.6 14.3 10.6 14.5 18.3 15.0 23.7 17.0 $64.50 Utility 14.7 14.7 14.7 Michigan 17.6 18.0 Heathkit EA-3 Professional 13.9 15.1 13.9 15.3 15.5 18.3 18.9 "14 w. H1 FI" High Fidelity 15.5 16.2 15.8 a subsidiary ofDaystrom, Inc. 16.6 16.4 19.0 19.5 $29.95 Utility 16.4 16.5 the The Hea WI amplifier power rating standards have been established as further assurance to you of high quality of our products. We will live by these standards until industry-wide standards are established.

8 AUDIO AUGUST, 1959 .4 5 H EATH KIT

style performance quality STEREO EQUIPMENT CABINET KIT MODEL SE -1 (center unit) $14995 cosfiä you, 644! MODEL SC -1 (speaker enclosure) ;3995 Snug. Wt. 42 Ws each

Superbly designed cabinetry to house your complete stereo system. Delivered with pre -cut panels to fit Heathkit AM -FM tuner (PT-1), stereo preamplifier (SP -I & 2) and record changer (RP -3). Blaik panels also supplied to cut out for any other equipment you may now own. Adequate space also provided for tape deck, speakers, record storage and amplifiers. Speaker wings will hold Heathkit SS -2 or other speaker units of similar size. Available in unfinished birch or mahogany plywood.

MONAURAL- STEREO PREAMPLIFIER World's largest manufacturer of KIT (Two Channel Mixer) electronic instruments in kit form MODEL SP -2 (stereo) $56.95 Shpg. Wt. 15 lbs. MODELSP -1 (monaural) $37.95Shpg. Wt. 13 lbs. HEATH COMPANY MODEL C -SP -1 (converts SP -1 to SP -2) $21.95 Benton Harbor, 25, Michigan Shpg. Wt. 5 lbs. Special "building block" design allows you to purchase instrument in monaural version and add bsld/ary of Dayatrom, Inc. stereo or second channel later if desired. The SP -I monaural preamplifier features six separate inputs with 4 input level controls. A function selector switch on the SP -2 provides two channel mixing. A 20' remote balance control is provided.

,\ HIGH FIDELITY RECORD CHANGER KIT MODEL RP -3 $6495

Turntable quality with full) :un Un141IC features! A unique "turntable pause" allows record to fall gently into place while turntable is stopped. The tone arm engages the motionless record. and a friction clutch assures smooth start. Automatic speed selector plays mixed 331:, and 45 RPM records regardless of sequence. Four speeds available: 16, 331,. 45 and 78 RPM. Changer complete with GE -VR -I1 cartridge with diamond LP and sapphire PROFESSIONAL STEREO -MONAURAL 78 stylus, changer base, stylus pressure gauge and 45 RPM spindle. Shpg. Wt. 19 lbs. AM -FM TUNER KIT

MODEL PT -1 $8995 "EXTRA PERFORMANCE" 55 The 10 -tube FM circuit features AFC (automatic WATT HI -FI AMPLIFIER KIT frequency control) as well as AGC. An accurate A real work horse packed with top quality tuning meter operates on both AM and FM while features, this hi -fi amplifier represents a a 3- position switch selects meter functions without remarkable value at less than a dollar per stereo disturbing or monaural listening. Individ- watt. Full audio output at maximum ual flywheel tuning on both AM and FM. FM damping is a true 55 watts from 20 CPS sensitivity is three microvolts for 30 db of quieting. to 20 kc with less than 2''; total harmonic The 3 -tube FM front end is prewired and pre - distortion throughout the entire range. aligned, and the entire AM circuit is on one printed Featuring famous "bas -bal" circuit, push - circuit board for ease of construction. Shpg. Wt. pull EL34 tubes and new modern styling. 20 lbs. Shpg. Wt. 28 lbs.

AUDIO AUGUST, 1959 9 HIGH FIDELITY AM TUNER KIT MODEL BC -1A $2696 Designed especially for high fidelity applications this AM tuner will give you reception close to FM. A special detector is incorporated and the IF circuits are "broadbanded" for low signal NOTE THESE OUTSTANDING SPECIFICATIONS: Power Output: distortion. Sensitivity and selectivity are excellent le watts. Hi-Fi; 12 watts. Professional; 18 watts. Utility. Power Response: is assured by a high kc 14 watts Total Harmonie Dlatarne.: and quiet performance * 1 db Irom 20cps to 20 at output. less than 2%. 30 cos to 15 kc at 14 watts output. I,darmodulatlon Distor- signal -to -noise ratio. All tunable components tion: less than 1% at 16 watts output using 60 cos and 6 kc signal mined 4:1 "best Hum and Noise: snag. phono input. 47 db below 14 watts: tuner and crystal are prealigned before shipment. Your buy" phono. 63 db below 14 watts. in an AM tuner. Shpg. Wt. 9 lbs.

14 -WATT HI -FI ECONOMY AMPLIFIER KIT MODEL EA -3 $2996 MODEL FM -4 From HEATHKIT audio labs comes an exciting new kit ... New $$496 Styling, New Features, Brilliant Performance! Designed to function (with cabinet) as the "heart" of your hi -fi system, the EA -3 combines the pre- amplifier and amplifier into one compact package. Providing a full tf 14 watts of high fidelity power, more than adequate for operating the HIGH FIDELITY FM TUNER KIT (FM4) average system, the EA -3 provides all the controls necessary for the latest precise blending of musical reproduction to your individual taste. The all new model FM-4 incorporates include Clearly marked controls give you finger -tip command of bass and advancement in circuit design. Features treble "boost" and "cut" action, switch selection of three separate better than 2.5 microvolt sensitivity for 20 db inputs, "on -off" and volume control. A hum balance control is also of quieting, automatic frequency control (afc) provided. The convenient neon light on the front panel shows with defeat switch, flywheel tuning and prewired, when instrument is on. Styled to blend harmoniously into any room prealigned and pretested tuning unit. Prealigned surroundings, the handsome cover is of black vinyl coated steel with IF transformers and prewired tuning unit assure gold design and features the new "eyebrow" effect over the front panel easy .assembly with no further need of alignment to match the other new Heathkit hi -fi instruments. The panel is satin after unit is completed. The five tube circuit fea- black with brush -gold trim strip, while the control knobs are black tures a generous power supply utilizing a silicon with gold inserts. Shpg. Wt. 15 lbs. diode rectifier. Shpg. Wt. 8 lbs.

12 WATT "MSTER CONTROL" PREAMPLIFIER KIT "UNIVERSAL" HIGH FIDELITY AMPLIFIER KIT MODEL (Not Illustrated): MODEL UA-1 $2196 controls you need master á cómplete high fidelity system Ideal for stereo or monaural applications, this Incorporated in this versatile instrument. Features 5 swttch- 12 -watt power package features less than 2% selected inpu s each with level control Próvides tape recorder and total harmonic distortion throughout the entire ca hode-follower outputs. Fll frequency obtained within audio range ( 30 to 15.000 CPS) at full I2 -watt I1dbfrom 35x000 GPS and will to the finest output. Use with preamplifier models WA -P2 available program sources. Equalization is LP, RIAA, or SP -I & 2. Taps for 4, 8 and 16 ohm speakers. AES, and early 78 records. Shpg. W . 7 lbs. Shpg. Wt. 13 lbs. NEW! MODEL TR-IA: Monophonic halttrack record /pla back with fast forward and rewind $9996 functions. Shag. Wt. 24 lbs.

MODEL TR-1AH: Half -track monophonic and stereo record /playback with fast forward Si /E 996 and rewind functions. T .7 Shag. WI. 35 lbs.

MODEL TR -IAO: Ouarter.track monophonic and stereo with record /playback fast forward and rewind functions. Shoe. Wt. 35 lbs. $14996

NOW! TWO NEW STEREO -MONO TAPE YOU'RE NEVER OUT OF DATE RECORDERS IN THE TR -1A SERIES WITH HEATHKITS Heathkit hl -fi systems are designed for maximum flexi- Offering complete versatility, the model TR -IA series tape recorders bility. Simple conversion from basic to complex systems enable you to plan your hi -fi system to include the functions you want. or from monaural to stereo is easily accomplished by Buy the new half-track (TR -I AH) or quarter -track (TR -I AQ) versions adding to already existing units. Heathkit engineering which record and playback stereo and monophonic programming, skill is your guarantee against obsolescence. Expand or the half-track monophonic record -playback version (TR -1 A). your hi -fi as your budget permits ... and, if you like, Four -pole, Precision parts hold flutter and wow to less than 0.35%. spread the payments over easy monthly installments functions. fan cooled motor. One control lever selects all tape handling with the Heath Time Payment Plan. Each tape preamplifier features NARTB playback equalization, sepa- rate record and playback gain controls, cathode follower output, mike or line input, and two circuit boards for easy construction and high stability. Complete instructions guide assembly. AUGUST, 1959 10 AUDIO CONTEMPORARY Model CE -1B Birch CHAIRSIDE ENCLOSURE KIT Model CE -1M Mahogany MODEL CE -1 $4395 each Control your complete home hi -fi system right from your easy chair with this handsome chairside en- closure in either traditional or contemporary mod- els. It is designed to house the Heathkit AM and FM tuners (BC -IA and FM -3A) and the WA -P2 preamplifier, along with the RP -3 or majority of record changers which will fit in the space provided. Well ventilated space is provided in the rear of the enclosure for any of the Heathkit amplifiers de- No Woodworking Experience signed to operate with the WA -P2. The tilt -out Required For Construction. shelf can be installed on either right or left side as desired during the construction, and the lift -top All Parts Precut á Predrilled lid in front can also be reversed. All parts are pre- For Ease of Assembly. cut and predrilled for easy assembly. The con- temporary cabinet is available in either mahogany TRADITIONAL Maximum Overall Dimensions: or birch, and the traditional cabinet is available in Model CE -IT Mahogany mahogany suitable for the finish your 18" W. x 24" H. x 35%" D. of choice. All hardware supplied. Shpg. Wt. 46 lbs.

"BASIC IT'S EASY .. . IT'S FUN RANGE" HI -FI SPEAKER SYSTEM KIT AND YOU SAVE UP TO The modest cost of this basic speaker sys- WITH DO -IT- YOURSELF HEATHKITS tem makes it a spectacular buy for any hi -fi enthusiast. Uses an 8' mid -range Putting together your own Heathkit can be one of the most woofer and a compression -type tweeter to exciting hobbies you ever enjoyed. Simple step -by -step in- cover the frequency range of 50 to 12,000 structions and large pictorial diagrams show you where CPS. Crossover circuit is built every part goes. You can't possibly go wrong. No previous in with balance control. Im- electronic or kit building experience is required. You'll pedance is 16 ohms. Power rat- learn a lot about your equipment as you build il, and, of ing 25 watts. Tweeter horn ro- course, you will experience the pride and satisfaction of tates so that the speaker may having done it yourself. be used in either an upright or horizontal position. Cabinet is made of veneer -surfaced fur- niture-grade plywood suitable for light or dark finish. All wood parts are MODEL precut and predrilled SS -2 $3995 for easy assembly. Shpg. Wt. Legs: No. 91 -26 Shpg. Wt. 3 lb. $4.95 26 lbs.

DIAMOND STYLUS HI -FI PICKUP CARTRIDGE LEGATO HI -FI SPEAKER SYSTEM KIT MODEL MF -1 $2696 MODEL HH -1 $29995 Replace your present pickup with the MF -1 The startling realism of sound repro- and enjoy the fullest fidelity your library of duction by the Legato is achieved LP's has to offer. Designed to Heath specifica- through the use of two 15' tions to Altec offer you one of the finest cartridges Lansing low frequency drivers and a available today. Nominally flat response from specially designed exponential 20 to 20,000 horn CPS. Shpg. Wt. 1 lb. with high frequency driver. The special crossover network is built in. Covers "RANGE EXTENDING" HI -FI 25 to 20,000 CPS within ± 5 db. Power SPEAKER SYSTEM KIT rating 50 watts. Cabinet is constructed ì/4' The SS -1B employs a 15' woofer and super of veneer- surfaced plywood in tweeter to extend overall response of basic either African mahogany or white SS -2 speaker from 35 to 16,000 CPS db. birch suitable for the finish of your t5 choice. All Crossover circuit is built in. Impedance is 16 parts are precut and pre - ohms, power rating 35 watts. Constructed of drilled for easy assembly. Shpg. Wt. 3/4' veneer -surfaced plywood suitable for light 195 lbs. or dark finish. Shpg. Wt. 80 lbs.

HEATH COMPANY BENTON HARBOR 25, MICH. pioneer in G1 MODEL SS -1B bsidiary of Daystrom, Inc. $9995 "do -it-yourself" electronics Please send the Free Heathkit catalog.

Enclosed find E name Please enclose postag for parcel post- expres orders are shipped de livery charges collect All prices F.O.B. Benton address Harbor. Mich. A 20% de posit is required on al C.O.D. orders. Price subject to change with city d state out notice. SEND FOR FREE CATALOG QUANTITY Describing over 100 easy -to -build ITEM MODEL NO. PRICE kits in hi -fi, test, marine and ham radio fields. Also contains com- plete specifications 'and sche- matics.

AUDIO AUGUST, 1959 11 and one side is solid windows, the other sides mostly hard, shiny blackboards. Tile floor, varnished wooden chairs carved in fiat planes. Phew! The sound that ema- nates from my speakers is vaguely like the rumble of a subway train on a sharp curve. If you listen hard, you can tell that it is music that is playing.l The odd thing is (and I've noticed this before, in other similar situations) that in this hard, bright, utterly plane -surfaced room, what you hear is all bass and no U -3's highs. For a moment, I thought the AR were connected with the tweeters out. Not 61ward ratnall Canby at all; they were turned all the way up, mid- range. I managed to melt away. It's a nice feeling, a heartening both highs and 1. PLAY RECORDS AND LIKE IT get a slight and relative improvement by- one, if slightly provincial. I am five days' regular believe it or not -boosting the highs to the As of this writing, You see, if the United Nations and the mail from home, two days' air mail, and maximum and rolling off the bass all the Bomb don't get mentioned very often here, territory seems so wholly removed from way, plus the rumble cut -off set at a fairly the time to bother with the world of audio that I can scarcely get because there isn't drastic position. myself to write on that honored subject. them and there's practicing to be done, Worst of all, it didn't seem to make But it is good for me, of course, to get work to fill every moment of a musician's really very much difference what I did away from the hectic center of things and life-then audio, too, seems generally dis- with the controls, nor what I played. All see how records and hi fi look to the big tant and not so very important, all in all. records, including the deadest ones I know, outside world in its millions of small cor- Records are nice, of course, but real work, sound ultra-live and thoroughly scrambled. ners, of which this is one. Where am If Not real music is so much more to the point - Two speakers. I tried to check their Pakistan, nor Durban nor even Yokohama, and practice, practice, practice; that's phasing via a mono record played through but just plain Tennessee. I got a letter what really has to count. Records are like both -and found that it didn't make the this morning from Bartok of Bartok candy, and apt to make one sick if taken slightest difference which way I set the records in New York that was mailed just in more than tiny doses -sick for lack of polarity. The reverberation was so tre- seven days ago. That's how far away I am. music practice. Time is of the essence, and mendous that every last vestige of phasing Down here, audio, hi -fi and records make it's not for leisure -especially, listening to was effectively blurred out. Stereo? Here I a subject for an experiment in teaching records. had brought a thousand -odd dollars' worth which I believe is quite novel and perhaps To be sure, the bassoonist from the Pitts- of stereo equipment all the way to this untried to date. I'm teaching hi fi -plus burgh Symphony who lives next door to me blarsted room and I immediately found sixteenth century motets -to an enterpris- in the big stone college dormitory named that in it there was not the slightest aud- ing batch of budding professional musi- Cleveland Hall, has a Magnavox and a cat. ible difference between stereo and mono cians, average age about sixteen, who are Each morning before our 7:30 breakfast sound -phasing quite aside! being trained by a faculty of professional he puts on one record, shaves, feeds the cat It's an odd spot for an audio man to be symphony players. The Sewanee Summer and rushes out to play bassoon. Each noon in, but not actually an unusual one, come Music Center is encamped on a lovely old he comes back, plays a record, cleans up to think of it. Don't forget that records, mountain campus, the University of the the cat's mess, if any (often), and rushes most providentially, sound decidedly at teach bas- South, for five weeks of concentrated music - out to play bassoon again, or their best in the acoustics of the average making-fiddle players, trombones, horns, soon. Same, ditto, idem, various other home living room- indeed, they are tailor - bassoons, clarinets, oboes, each group times. He gets a surprising amount of made for the living room and generally find ardently coached by the professional sym- music in, this way (hi -fi on records, I themselves painful misfits in most other phony specialist for the given instrument. mean), though it is only natural that al- acoustics. Class rooms, lecture halls, stu- When they rehearse, under a big tent on a most every piece lie plays has a bassoon in dent lounges and the like are not designed very green and leafy lawn, these kids play it. (Bassoons play in practically all music, for record listening and no reason why they manfully (and girlfully) with a concentra- when you come down to it, so he has plenty should be. But unfortunately, if one is to tion that should make any teacher envious. to choose from.) give illustrated lectures on records, with They can't be stopped. They take their I brought down some 500 records, about records, the class room is the place it ordi- harmony lessons to the swimming beach four -fifths of them stereo, to represent the narily has to be done. You members of lo- with them and study between dips. They huge present recorded library. The rear end cal hi -fi clubs will know all too well what I eat, drink, blow, scrape and pound music of my car practically hit the ground under mean. Have you found a really good place all day long. the weight. I also crammed in a pair of to hold your musical meetings -one that It would make you envious too, I'm eure, AR -3 speakers and another pair of KLH will hold the audience and treat the re- if you happened to be thinking about the Sixes -plus my complete Dynakit system corded sound rightly? young engineering students whom you may and a spanking brand new Fisher 300 The physical blur of recorded music in know. These kids get up at five in the stereo outfit. Also mikes, tape, a four -track my class room (I've been spending today morning to practice, or stay out of bed recorder, and other paraphernalia galore. trying to locate a replacement room some- surreptitiously until the wee hours, against You should have seen my packing job for where else) is compounded by the second camp regulations, to hide themselves in a the thousand-mile jaunt over the Blue reason for a alight delay in producing re- sound -proof practice room and hammer Ridge Parkway! sults here in this Tennessee music camp. away (or blow away) at their instruments. Unfortunately I am not yet able to re- (I haven't been here very long yet.) That No doubt about it, music -live music - port very much on this lovely array of hi is, of course, the musicians themselves. is a vital, living thing for a surprisingly fi. I can state positively that the Fisher My job, ever so tactfully, is to persuade large number of upcoming young folks. turned on and didn't blow a fuse, nor did these excellent, ardent, hard -working live They face up to the formidable, even terri- it hum. I can say equally well that both musicians that recorded music has some- fying complexities of skilled musical per- the AR-3 speakers produced a large volume thing to do with their lives. And, as of now, formance with the usual fortitude of youth, of sound. But beyond this I am presently I have to do my persuading in that room. and more than that. They study and play, stymied for two excellent reasons. Ugh. assigned find here, as though the world of the future First, I have -inevitably -been So my very first problem of all, is to room my here, like would certainly be conquered by clarinete a fine, big university class for a better listening place. People own first and bassoons, as though if only the right hi -fi lectures. It is the Devil's others everywhere, do not understand what the correct stance, the exact choice as the prize horror -room for listen- a whale of a difference room acoustics can embouchure, Not and lilt could finally be achieved by ing. Unbelievable! Solid concrete, utterly make -do make -in reproduced sound. rhythm square inch of each and every one of them, the problems rectangular, without one of any sort, 1 Why didn't you open the windows? ED. of nations and the nuclear bomb would padding or sound deadening AUDIO AUGUST, 1959 12 NEW STEREOPHONIC EQUIPMENT NEW AF -4 Complete Stereo Dual Amplifier not illcs.' provides clean 4W per channel or 8W output. Usual solid EI:0 construc- tion & trouble-free design. Inputs for ceramic /crystal stereo pick- ups. AM-FM stereo. FMMull: stereo: 6- positron stereo /mono mode selector: clutch-concentric level & tone controls. 27db of feedback around each power amplifier reduces distortion to at normal listening levels with hi- efficiency speakers the '1n.dco A04877M or equivalent recommended:. Kit $38.95. HF85. Stereo Dual Preamplifier is a complete stereo control sys- STEREO - uuette -an adaptable to any type of instal - vamp.' introls any stereo source tape,

.1. r Super). . r able crossover. feedback tone con- AND experts , ill 1., b, feedback amplifier pairs in each channel. Distor- tion borders on unmeasurable even at high output levels. Sep- M ONAURAL arate lo-leve) input in each channel for mag. phony. tape head, mike. Separate hi-level inputs for AM 8 FM tuners 8 I M Multiplex. One each auxiliary A 8 B input in each channel. Independent level. bass 8 treble controls in each channel may be operated say... together with built-in clutch. Switched -in loudness compensator. Function Selector permits hearing each stereo channel individu- ally. and reversing them: also use of unit for stereo or mono- phonic. play. Fulbwave rectifier tube power supply. 5- 124X7/ ECC83. 1.6 %4. 'Works with any high -quality stereo power amplifier in HI -FI so: h as EICO HF86, or any 2 high quality mono power amplifiers such as EICO HF14. HF22. HF30. 11F35. HBO. HEW. "Extreme flexibility . a bargain" - HI-FI REVIEW. Kit $39.95. Wired $64.95. Includes cover. HF86: Stereo Dual Power Amplifier for use with HF85 above or the best buys are any good self -powered stereo preamp. Identical Williamson -type push -pull EL84 power amplif:ers. conservatively rated at 14W, may be operated in parallel to deliver 28W for non- stereo use. Either input can be made common for both amplifiers by Service Selector snitch. Voltage amplifier 8 split -load phase inverter circuitry feature EICO -developed 120W7 audio tube for signifi- cantly better performance. Kit $43.95. Wired $74.95. HF81: Stereo Dual Amplifier- Preamplifier selects. amplifies 8 Wo -Id- famous controls any stereo source tape. discs. broadcasts 8 feeds it thru self-contained dual 14W amplifiers to a parr of speakers. EICO advantages Monophonically: 28 watts for your speakers: complete stereo preamp. Ganged level controls. separate focus !balance'- control, guarantee your complete satisfaction: independent full -range bass 8 treble controls for each channel. Identical Williamson-type. push -pull EL84 power amplifiers, ex- cellent output transformers. Service Selector" switch permits Advanced engineering Finest quality components one preamp- control section to drive the internal power ampli- LrLIP other preamPcontrol section is left 'ree to drive "Beginner- Tested," easy step -by -step instructions -t external amplifier "Excellent" SATURDAY REVIEW: IC AT HOME. "Outstanding quality ... extremely ver- L FETIME service & calibration guarantee satile" RADIO & TV NF:c'S LAB-TESTED. Kit $69.95. Wired $109.95. Includes cover IN STOCK - Compare, then take home any EICO MONO PREAMPLIFIERS (stack 2 for STEREO) equipment -right "off the shelf" -from 1900 neighbor- HF.65: superb new design. Inputs for tape head. microphone, Leona cartridge & hi -level sources. IM distortion 0.04 °6 hood FICO dealers. . / out Attractive "low silhouette' design. HF65A Kit $29.95. 544.95. HF65 with power supply Kit $33.95. Nired $49.95. MONO POWER AMPLIFIERS (use 2 for STEREO)

HF50 50W . HF35 35W . HF30 c30W HF22 22W), from Kit $23.50. 'hired $41.50. MONO INTEGRATED AMPLIFIERS (use 2 for STEREO)

HFr_ HF32 30W . HF20 20W . HF12 12w from Kit 534.95. 557.95.

10.. T SPEAKER SYSTEMS (use 2 for STEREO) HFS2: i,.i 5 30-200 cps via slot-loaded split conicalcon 4 bass horn. Middles 8 lower high`: front rad12-It.tiiaon from 8 :/a" Stereo Preamplifier HF85 edge -damped cone. Distortionless spike-shaped super-tweeter radiates omni- directionally. Flat 4520.000 cps. useful 30-40.000 cps. 16 ohms HWD 36 ". 15i4 ". Ilr: ". "Eminently musical"- - Holt. HIGH FIDELITY. 'Fine for stereo" MODERN HI-Fl. Corn - pletele factory-built: Mahogany or Walnut. $139.95; Blonde, FM Tuner HFT90 5144.95. AM Tuner HFT94 HFS1: Bookshelf Speaker System, complete with factory -built abinet. Jensen 8" woofer. matching Jensen compression-driver exponential horn tweeter. Smooth clean bass: olsp extended highs. 7012.000 cps range. Capai ity 25 w. 8 ohms. HWD 11" x 23" x 9 ". Wiring time 15 min. Price $39.95. L0S-1 Brass Tip Stereo Matching 14" Legs easily convert HIS -1 into attractive conso- Amplifier -Preamp cette. All brackets & hardware provided. $3.95. HF81 FM TUNER HFT90: A superior stable tuner easy to assemble no instruments needed. Prewired. prealigned. temperature-com- pensated -front end" is drift -free, eliminates need for AFC. Pre - wired exclusive precision eye-ironick traveling tuning indicator -ontracts at exact center of FM channels. Preal igned IF coils. Sensitivity 6X that of other kit tuners: 1.5uv for 20db quieting: 2.5uv for 30db quieting. full limiting from 25uv. IF bandwidth 260kc at 6db points. Frequency response 20- 20,000 cps 2 output lacks: cathode follower to amplifier, Multiplex output for FM Multiplex Stereo adapter. thus prevents obsolescence. Very low distortion. "One of the best buys in high fidelity kits" AUDIOCRAFT. Kit $39.95'. Wired Cover Bookshelf $65.95'. $3.95. Speaker Monaural Integrated Amplifiers: System HFS1 NEW AM TUNER HFT94: Matches 111190. Selects "hi-fis' wide 50, 30, 20, and 12 20e a -Watt 9kc 3 db or weak -station narrow (20c - Skc ir 3 (use 2 for Stereo) db bandpass. Tuned RF stage for high selectivity & sensitivity: precision eye -tonic. tuning. Built-in ferrite loop. prealigned RF 8 IF coils. ,r °0 Omni -directional Sensitivity 3 uv 30 mod. for 1.0 V out. 20 db S /N. Very low noise 8 distortion. High -0 kc Monaural Preamplifiers( Speaker System HFS2 10 whistle filter. Kit $39.95. 'Nued $69.95. Prices Inc,. Cover 8 F.F.T. HF65, HF65A 36" H x 1544" W z 111/z" 0 (stack 2 for Stereo) EICO, 33.00 Northern Blvd., L.I. C. 1, N. Y. A -8

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AUDIO AUGUST, 1959 13 The AR -3 is a three -way speaker system. even enough engineers understand it. Most of us are lucky; rooms, combining an AR -I acoustic suspension our living by the happy chance of current decorating styles, woofer with two high -frequency units developed are usually quite good for recorded sound. in AR's laboratory over the last year. A few years ago, many a living room was too dead for listening comfortably, what with rugs, pillows, heavy drapes, plush sofas. Now, the modern trend has brought in more hard furniture, less absorbent drapery and upholstery. But it hasn't gone so far as to leave our living rooms bare and chilly, like the average classroom! Not that. To be sure, there's a marvelous listening room up our University avenue a ways, in a comfy old fraternity house with all sorts of nooks, balconies, wooden paneling, car- pets, a peaked roof. Superb -but it happens to be in the Director's private home and isn't properly available. There's chamber music to be played there all day long (and what a lovely sound), with small time left for any other purpose. But ah! what a lovely sound from a stereo tape, too, that Like the AR woofer, the tweeters used in the AR -3 I played in there the other evening! I'm represent a radical departure from conventional going to have to wangle my way into that speaker design, and patent application has room willy -nilly unless I can find its double somewhere else. been made.* (There surely is nothing like putting your theories to the test. I'm testing my pet These new tweeters are neither cone -type nor ideas on recorded sound with a vengeance horn devices -they could be described technically here.) as hemispherical direct -radiators. We believe But back to the musicians. The bassoon, that their uniformity and range of frequency the clarinet, the horn are simply too busy learning about records response, their low distortion, and their transient to spend their lives and, as specialists in a very demanding art and dispersion characteristics establish new I cannot in the least blame them. There's performance standards, and that the AR tweeters work for them to do and no end to it, ever. make a contribution to treble reproduction But what makes things more interesting is other faculty members among similar in degree to that made by AR's acoustic that some these musicians are a lot more than merely suspension woofer to bass reproduction. indifferent to the joys of record listening and the complexities of audio acoustics, The AR -3 has the most musically natural sound stereo and what -not. These others, like that we were able to create in a speaker, many musicians the country over, actively without compromise. distrust, even hate recorded music. They feel, and have told me so elsewhere as well Potent applied for by E. M. Vilichor, assignor to Acoustic that records are not only murder- Research, Inc. as here, ous to the actual sound of real music but, more important, they are passionately con- vinced that recorded sound has already threatened the entire art of music and is well on its way towards killing off the musicians himself and his livelihood. Rec- ords, from this musician's point of view, are an ominous force that is undermining their whole way of life. Audiences are vanishing from their concerts, young peo- ple find jobs elsewhere, musicians are quit- ting by the hundreds, disillusioned, stan- dards of playing are going down .... it's a dismal story to hear, and it does make you pause to think. Here I am, an enthusiast for this very enemy of theirs, right in their own camp - teaching their own young musical hopefuls all about records! It's a bit hard on the musicians and not too easy for me, though it is a tremendous challenge to see whether I can't convince some of these pleasant people here that neither I nor my records The AR -3 speaker system, complete with the and my hi -fl are here to bite them, so to necessary "bookshelf" size enclosure, is speak. In a microcosm, on this campus, we $216 in mahogany or birch -prices in other woods have the very essence of the musician's problem today. The situation, if it weren't vary slightly. Literature on the AR -3 is so real, so isolated, so intense, could be available for the asking. tremendously interesting for all of us- and probably will be before I leave. The problem I face, of course, is not ACOUSTIC RESEARCH, INC. 24 Thorndike St., Cambridge 41. Mash. how to solve these musicians' future for AUGUST, 1959 14 AUDIO LESA -É ARRIVATO! Translation: LESA - IT HAS ARRIVED! In any language, this is truly welcome news for all Hi -Fi enthusiasts and would -be enthusiasts searching for professional quality at an amateur price. Just one quick look and a listen will show you why we say "Custom crafted in the world famous Italian tradition of unsurpassed quality and lasting beauty." You'll especially want to see the smartly styled CD2/21 record changer - never before such quality at anywhere near the price! Fully automatic, 4 -speed pre -wired for mono and stereo automatic size intermix flutter, wow and rumble of broadcast standards smooth action, 6- second change cycle guaranteed jam -proof universal plug -in head heavy duty 4 -pole motor precisely balanced no- resonance, no- feedback tone arm. 4f4v 4N Pc

audiophile net

PORTABLE STEREO SYSTEM MINIATURE RECORD PLAYER Brand new! The LESAPHON high fidelity and You've never seen a 4 -speed manual record player of the companion LECOSTEREO amplifier- speaker. Use the LESAPHON small size, small price and big quality performance of the with its CD2/21 changer and high power sound system Lesa 4V3/11. Pre -wired for monaural and stereo, it plays for brilliant monaural sound reproduction. Or simply plug all size records. Automatic stop at end of record play. Turn- in the LECOSTEREO for superb stereo with single point vol- table speeds are accurately controlled, constant to within ume control. Both in matching finish with brass trim. 1.5 %. Elastic suspension mounting insures smooth, steady Lesaphon Model 57 /SA with stereo cartridge $125.95 net operation. Lecostereo Model 1 /SA with shielded cable $ 63.95 net Model 4V3/11 with universal plug-in head $23.25 net

SEND FOR FREE LITERATURE AND 2 3 NAME OF YOUR NEAREST DEALER Electrophono & Parts Corp. 530 Canal Street, New York 7, N. Y.

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Address

City lone State

AUDIO AUGUST, 1959 15 them, which I can't do, but simply to get their attention. There aren't many argu- ments because everybody is much too busy to argue -even the bassoonist with his Magnavox. He plays records but he's not interested in them as records, nor how they work. He just wants to hear the music on them. An admirable idea and, I must con- fess, a rather pleasant one for me, who spend most of my time trying to persuade hi -fi fans to pay more attention to music and less to the cycles and the IM distortion. And I confess, too, that my own resolu- tion is hard put, here. I tend in this in- Fairchild is a way of sound tense area of active music- making to lose interest in my own records. I, myself, want to hear this live music; I am almost apolo- Model SM -1 Rotating Magnet Stereo /Mono- phonic Cartridge. Rotating ball magnet for getic when I suggest that maybe the stu- permanent channel separation; wide, smooth dents ought to have a few hours now and response. Complete mumetal shielding. then during which they could listen to my Easily replaceable 0.6 mil diamond stylus. 500 discs and study what other musicians Extremely high output . 16.2 my @ 7 cm /sec and 1 kc. Complete with install -a- are doing in the great, big outside world. kit screw driver and gram gauge. $34.95 But I mustn't be apologetic. I tell myself Replacement stylus assembly $15.00 that records are here to stay, that audio is a great, big field unto itself, that hi -fi, for all its goofiness, is a big industry and an even bigger cultural force in our life to- day. I assure myself, privately, that mil- lions of people are interested in records and in hi -fi, that an enormous new audi- ence for music has been created by the phonograph, that recording has revived vast areas of long- forgotten art that would never have been heard again were it not for the art of sound reproduction. I insist, to myself, that I am represent- ing, here in the mountains of Tennessee, one of the most dynamic artistic move- ments of our century, just as I am in this Model 262 Stereo Arm. Mass and spring magazine that you are now reading. counterbalanced for maximum tracking ac- all seems very in spite of curacy. Two plug -in cartridge slides provided. But it distant, Universally adaptable contact block permits me. Last night I forsook my tape recorder all leading cartridges to plug in without and went off to listen to Stravinsky, played soldering. Complete with integral 6 -foot plug - by seven of my new musician friends here. terminated leads. $42.50 It was terrific and lots better than any record. This afternoon, the next -door bas- soonist spent three hours teaching a lovely young lady student how to cut her own onif bassoon reeds. I was fascinated, for here Model 412-1 Double Belt -Drive Turntable. was old -line craftsmanship of a sort you 331 rpm. Resilient double belts on large wouldn't believe could still exist. Each of pulleys eliminate drive slippage, and keep his double reeds is cut and shaped by hand rumble to a minimum of 100% better than with a careful knife, the edge trimmed to tables. the NARTB standards for professional a Speed constant ±0.3%. $79.50 millimeter, the thickness carefully scraped down for hours to an exactly even taper and a perfectly symmetrical curve. FAIRCHILD is a way of sound ... a pattern for listening The canes for the reeds grow only in one ... a passport to musical enjoyment. All this is yours with part of France -they can't be had any- the acquisition of three pieces of fine FAIRCHILD equip- where else. They last a week or so, and then the bassoon (and oboe) player spends more ment: revolutionary rotating- magnet cartridge, double hours of handwork scraping and binding belt -drive turntable and double counter -balanced arm. another. Engineered by the pioneer in monophonic and stereo- Sure, it's like building a hi -fi kit in a phonic recording and reproducing equipment, these three, way; but suppose you had to go out and will add new dimension to make your own resistors and capacitors, either alone or in concert, draw your own copper wire and wind on your system. They will distinguish you as a person of the insulation. musical discernment, for FAIRCHILD up front puts your It's an interesting corner of the musical enjoyment way ahead. world, here in Sewanee, and no two ways about it. But I haven't yet been able to Write for complete specifications or consult your selected play a single record all the way through - FAIRCHILD dealer. anywhere on the campus. I'm not really sure I want to, at that Phew! What am I saying? On with the Great Crusade, Canby. Get out and teach these musicians to play rec- FAIRCHILD RECORDING EQUIPMENT CORPORATION ords and like itl EW, 10-40 45th Avenue, Long Island City 1, N. Y. (Continued on page 64)

AUGUST, 1959 16 AUDIO New Stereo Tape Recorder Cybernetically engineered for intuitive operation

Fluid smooth, whisper giiict ... with fcather- mixing controls on both channels for com- ganged volume control. I lead cover removes, light touch you control tape movement bining "mike" and "line The SM -310 re- giving direct access to tape for easy editing. with the central joystick of your Newcomb cords and plays back half -track monaural The Newcomb SM -310 is a sleek, rugged, SM -310. This exciting new stereophonic also. So versatile is the machine that you compact record -playback machine, discreetly styled by an tape machine has been may record and playback on either or both eminent industrial designer in easy -to -live. cybernetically engineered to fit you. channels in the same direction. with shades of warm gray Intuitively, you and satin alumi- sense how to operate this The SM -310 is a truly portable unit which num...a gratifying, precision instrument for handsome instrument. The natural move- combines the features required by the pro- ment, the creative individual who is deep in the you find, is the correct movement. fessional and desired by the amateur for on- art of tape recording. Eight, tightly Loading is simple. -spaced utterly It is almost impos- location making of master stereo tapes. For pages are required in a new brochure sible to make a mistake. to The transport han- example, the SM -310 takes reels up to 101/2", describe the SM -310 in detail; send for your dles tape with remarkable gentleness, avoids has two lighted recording level meters ar- free copy. stretch and spilling. ranged pointer -to- pointer for ready compari- Advance showings in New York and Los The Newcomb SM -310 records stereo- son, has a 4 digit counter to pinpoint position Angeles phonically proves an unprecedented demand live from microphones or from without repeating on any size reel. For play- for this instrument. We broadcast or recorded material. urge those who de- There are back there are a "balance" control and a sire early delivery to place their orders now.

NEWCOMB AUDIO PRODUCTS CO., DEPT. T -8, 6824 LEXINGTON AVENUE, HOLLYWOOD 38, CALIFORNIA NEWCOMB SALES REPRESENTATIVES CALIFORNIA, San Francisco 3, William J. Purdy Co., 312 Seventh St.; COLORADO, Denver, Cox Soles Co., P. Tampa 9, O. Box 4201, So. Denver Station; FLORIDA, Morris F. Taylor Co., 4304 Corona St.; Winter Haven, F. M. Taylor Co., 940 Lake Elbert Drive; GEORGIA, East Point, M. F. Taylor Co., Box 308; INDIANA, Indianapolis 20, Thomas 8 Sukup, Inc., 5226 No. Keystone Avenue; MASSACHUSETTS, Brookline 46, Kenneth L. Brown, 54 Atherton Road; MARY- LAND, Silver Spring, M. F. Taylor P. Co., O. Box 111; MICHIGAN, Ferndale 20, Sholco, 23525 Woodward Ave.; Grand Rapids 6, S. E.; MISSOURI, Clayton Shako, 700 Rosewood Ave., 5, Lee W. Maynard Co., 139 N. Central; NEW YORK, East Meadow, Harry N. Reizes, 1473 Co., P. O. Box 123, Sylvia Lane; Syracuse 14, Poston -Hunter DeWitt Station; NORTH CAROLINA, Charlotte 5, M. F. Taylor Co., 1224 P. Dresden Drive, West; OREGON, Portland 8, Don H. Burcham Co., O. Box 4098; PENNSYLVANIA, Hellertown, M. F. Taylor Co., 534 Ellen St.; Lansdowne, M. F. Taylor Co., 275 Bryn Mawr Ave.; Pittsburgh 36, M. F. Taylor Co., 5436 Youngridge Drive; TEXAS, Dallas I, Wyborny & Yount Ave., West. Co., 408 Merchandise Mart Bldg.; WASHINGTON, Seattle 99, Don H. Burcham Co., 422 First EDITOR'S REVIEW

of the Philadelphia paper AUDIO ENGINEERING SOCIETY Paraphrasing the boast reads the Bulletin," we believe CONVENTION that "nearly everybody it is to say that "nearly everybody goes to the WITH PRESENTATION Of papers from all over THE New York Show " -at least that is what you think as well as from Europe and South this country when you are there. America, the Eleventh Annual Convention of the Audio Engineering Society will take place at the CONSUMER MAGAZINES Hotel New Yorker October 5th through the 9th. These we are not alone in deriding the sup- papers will cover the newest theories, developments, Apparently posed omniscience of consumer testing organizations and achievements in the audio field, and will include -the somewhat less than austere Punch had its inn- a thorough discussion of stereo. There will be a broad ings in the January 14 issue, a copy of which we just of sound recording and reproduction. coverage received from Gilbert Briggs. Punch "analysed" will be accompanied by the second The convention copies of Which? and Shopper's Guide, England's two of professional audio equipment, "noiseless" exhibit consumer "guidance" journals. is expected that the first introduced last year, and it This is one time we beat Punch to the punch -if Tech- number of displays will triple those of last year. you remember our editorial of April, 1957. And we nical sessions will be presented on a three -a -day basis have never had cause to change our opinion since. commencing at 9 :00 a.m. on October 5, and the annual banquet and presentation of awards will follow the MONODIC October 8. cocktail party on Thursday, Turning to another British publication, we find this continuing for one Beginning on the same day and interesting bit in the June issue of Wireless World. A the New York day after the AES Convention closes, chap writing under the nom de plume of "Free Grid" street High Fidelity Show will take place across the conducts a page each month titled UNBIASED, and his from the New Yorker in the Trade Show Building - lead article studies the language to find a really good but will most certainly not be "noiseless." People who word for single -channel reproduction. He believes the come to see high fidelity equipment expect to hear it correct word is "monodic," after agreeing that mon- also. aural is more offensive than monophonic, which is just plain dreadful. Cause of it all was BBC's patronage of THE WEST COAST SHOWS monophonic -which most of us use in this country as monaural, and which is officially The Institute of High Fidelity Manufacturers has an improvement over , is a con- just announced the dates and locations for the San accepted by the IHFM. Monodic, or single) and hodos (a way, Francisco and Los Angeles Shows. In the Bay City, traction of monos (one quoting from Wireless World. the location is Brooks Hall at the Civic Center, and path, or channel). Still in such combinations the "h" is usually the dates are January 27 to 31. we find that The Los Angeles show follows a few days later, dropped, as in electrode. comes when Free Grid attempts to opening at the Shrine Exposition Hall on February 10 The funny part for two stereo channels sharing the and continuing through the 14th. find the right word in multiplex. He claims the We will have further information about these two same radio channel -as be homodic -same channel -but he ex- important shows during the next few months-you word should become known as homostereo to distinguish will still have plenty of time to arrange for your pects it to broadcasting on two separate channels annual early -spring trip to the coast. In the meantime, it from stereo be called heterostereo. He concludes by there are the Rigo shows in many of the smaller cities which might the Yanks- that's us -will probably nearly one a week throughout the fall season - expecting that - and Greek and call it solo stereocasting. along with the Chicago and New York shows -the fuse Latin which proves that there are many ways to former at the Palmer House from September 18-20, All of have fun most of us never went to Oxford. and the latter October 5-10, as mentioned above. -but

AUDIO AUGUST, 1959 18 "IT TAKES TWO TO STEREO" *

...the perfect team for stereo! For matchless reproducton of stereo recordings - the Model 196 UNIPOISE Arm with integrated Stanton Stereo FLUXVALVE pickup and the GYROPOISE 800 airborne Stereotable. Only the Stanton Stereo FLUXVALVE has the exclusive "T- GUARD" stylus assembly with the parallel reproducing element so important for stereo... only the GYROPOISE Stereotable revolves on a bearing-of-air - in magnetic suspension ... only the Stereo FLUXVALVE is warranted for a lifetime. In plain truth, here is more to enjoy - from both stereophonic and monophonic records. Fine quality high fidelity products by PICKERING & Co., Inc., Plainview, N. Y.

FLU %VALVE, GYROPOISE, STEREOTASLE, T -GUARD UNIPOIsE. * NEWLY REVISED TAKES TWO -"IT TO STEREO " -ADDRESS DEPT B89 FOR YOUR FREE COPY.

AUDIO AUGUST, 1959 19 A Bell Telephone Laboratories Several hundred listeners, meeting in small groups several times a day for weeks at a time, are then asked to in noise appraisal rate the effect of noise on transmission of the various experiment simulated telephone calls. For the Bell System, the results of the study will be- native Hollander wears wooden shoes." "The come part of the over -all transmission objectives. At Bell "Nebraska has no seacoast." Laboratories, they will influence apparatus and systems "The daisy is a common wildflower." development work. - of modern day living. It As these syllables, words and sentences come in over Noise is a major distraction In a telephone re- the telephones, stand -ins for millions of Bell System sub- is also an enemy of the Bell System. line hum, switching scribers rate them for clarity of reception. ceiver during a call, it might be power or thermal noise, or perhaps atmospheric static. Bell From these tests, Bell Telephone Laboratories engineers Laboratories spends a great deal of time, effort and money to mini- determine what is objectionable noise, and work to keep this extraneous noise from becoming annoying tape record- mize it in telephone circuits. They begin by and to assure you of a trouble -free connection. ing background noise associated with working telephone circuits. Test statements of appropriate length and con- tent (such as those above) are read onto a second tape, BELL TELEPHONE LABORATORIES and both are fed onto the test circuit under carefully con- trolled conditions. A third tape, of normal room noise, research and development is played through a loudspeaker in the test lab. World center of communications Transistor Music System Using Direct Coupling

RICHARD S. BURWEN

Using 13 transistors with direct coupling and 57 db of negative feedback results in only .01 per cent low- frequency harmonic distortion in a 20 -watt class B battery- operated power am- plifier. The 11- transistor control unit uses three direct- coupled feedback amplifier sections to provide phono equalization, tone controls, a four -channel mixer, and speaker equalization.

DISTORTIONLESS PERFORMANCE in their heat to the main chassis. The only IMW 10MW 0.IW I 20W transistor audio equipment requires controls are on and off push buttons 10 a great deal of negative feedback. which operate a latching relay. Not r Direct coupling makes possible the use shown are four mercury flashlight -size 5 of large amounts of stable feedback in cells and a 45 -volt battery somewhat the music system to he described. larger than the 8" x 6" x 31/2" aluminum Three matched components comprise chassis. the system : a 20 -watt power amplifier, a In order to minimize the battery drain tone-control preamplifier, and a speaker and internal heat the output stage is 1.0 10K, system. Battery operation and compact operated in class B with an efficiency of construction make the system suitable 69 per cent at maximum sinusoidal out- 0.5 w for both home and portable use. To pro- put. Since the average power input when z duce over -all pleasing sound and wide reproducing speech and music is much F á acoustic frequency response, fixed equal- smaller than for steady signals, the aver- _ ization which compensates for speaker age may be as current drain per hour W system inefficiency at the extremes of the 40 ma 45 volts 2.2- K low as at while ampere 0.1 audio range is incorporated in the tone peaks are being delivered to the load oc- a. control preamplifier unit. casionally. The current drain at no -sig- nal is only 27 ma. 05 Power Amplifier As a result of the low average power The power amplifier, Fig. 1, delivers input, battery life is between 10 and 100 20 watts to an 8 -ohm load with an input hours depending upon how loudly music 5001 z.//J of 0.4 volts rms into 3300 ohms. Identi- is played. Smaller batteries can be used Yr1oti cal 55 -watt power transistors, direct when reduced life is acceptable, but the .01 -50 -40 -30 -20 -10 0 +10 coupled to the load, are mounted at the power output is reduced because of their upper left on a bracket which conducts lower output voltage at high currents. db REFERRED TO 20 WATTS OUTPUT

Boston Division, Minneapolis-Honey - Although capable of only 40 -watt un- Fig. 2. Power amplifier total harmonic well Regulator Co. distorted peaks the amplifier can fre- distortion vs. power output at 10, 500, and 10,000 cps quently be operated under overload con- ditions with remarkably good results. Its sharp overload characteristic and its practically instantaneous recovery when the input signal is reduced below the clipping level minimizes the audible ef- fect of overload during occasional peaks. When used as a speech clipping am- plifier feeding the associated speaker system, the input signal may be increased as much as 10 db above the overload Fig. 1. 20 -watt di- point with little audible distortion on rect- coupled tran- speech. Since the missing peaks do not sistor power am- noticeably affect the average loudness, plifier. the effective output is that of a 200 -watt amplifier. Thus as a portable public ad- dress amplifier it has tremendous power. When reproducing music fairly clean - sounding signals can be delivered at ef- fective outputs between 40 and 200 watts depending upon the low- frequency content of the program material. Over-

AUDIO AUGUST, 1959 21 loaded bass notes generally are intoler- quencies with phase shift at high fre- suiting in true push -pull operation with able whereas cymbals and brass instru- quencies approaching that of only one identical output transistors. ments may sound undistorted when the stage. In the megacycle region, the direct Examining the circuit more closely, amplifier is delivering square waves 30 signal path through the base -to- emitter Q, feeds directly the base of the common per cent of the time. The maximum in- capacitances of the emitter-followers re- emitter PNP transistor Q, and through crease in audible output when the ampli- duces their phase shift and helps stabi- two biasing diodes the base of the NPN fier is delivering square waves nearly all lize the over -all feedback loop. common -emitter transistor Q,. The col- the time and sounds very distorted is Following Q, are four stages of push - lector signals of Q, and Q, are in phase about 13 db. pull class B amplification Q, through but referenced to different d.c. supply Q1,- Except at the common input and voltages. Q, then feeds a three -stage Direct Coupling common output there is no connection feedback amplifier Q Q and Q1,. Except for one coupling capacitor at between the sides of the four push -pull Common emitter NPN transistor Q, de- the input all 13 transistors in the sche- stages. Both power transistors Q1, and livers a low- current signal centered near matic, Fig. 3, are direct coupled. The Q1, are of the same 55 -watt PNP type. ground potential with a swing of ± 18 input transistor Q, is a low -noise emit- Push -pull operation is accomplished by volts. Emitter- follower Q capable of. ter- follower needed to drive the high a series connection with Q,t powered by 100 ma output, drives emitter follower input capacitance of Q a PNP common - - 22.5 volts and Q,, by + 22.5 volts. In Q,, to deliver 2.2 ampere peaks to an B- emitter amplifier. Q, also compensates order to establish the proper d.c. levels ohm load connected between J and J,,. changes in the base -to-emitter voltage of and driving voltages the sequence of In the lower section, Q, feeds emitter- Q, with temperature by means of the NPN and PNP stages driving Q,, is followers Q10 and Q which amplify the opposite change in its own base -to -emit- different from the sequence driving Q,,. signal current to provide up to 100 ma ter voltage. Q, has a very high voltage In the upper section of the circuit drive for the common -emitter output gain of 2500 obtained by using an ex- stages Q Q Q,, and Q all conduct at stage Q,,. Only Q has a large collector tremely high collector load impedance. the same time to deliver negative output swing. This load impedance consists of the high signals at J,,. Q, and Q, are common - For push -pull class -B operation at low while Q, are collector impedance of the NPN transis- emitter stages and Q distortion only one output transistor Q, is by emitter -followers. In the lower section tor which further increased must conduct at a given time except dur- emitter degeneration. Q, and Q, are of the circuit Q9, Q,,, and Q,, all Q, ing a small overlap region which is emitter -followers used to minimize the conduct at once to deliver positive out- necessary to prevent crossover distor- loading on Q,, provide a low output im- put signals. Common- emitter stage Q, is Q,, is its current pedance, and by means of a voltage di- followed by two emitter -followers Q tion. When conducting vider reduce the d.c. output level to ap- and Q,, and then the final common emit- output per volt delivered by Q or proximately ground potential. ter stage Q,,. Since there are two stages transconductance, must equal the current This combination of three emitter -fol- in each section that invert phase and delivered by Q,, when it conducts. At lowers and one common- emitter stage has two stages that do not, the output sig- crossover each transistor should con- a total voltage gain of 1800 at low fre- nals from Q,, and Q,, are in phase, re- tribute one -half the total output signal

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Fig. 3. Schematic of power amplifier.

22 AUDIO AUGUST, 1959 turned on and off by either local or re- I mote control push -buttons. I 0 db31 WATTS " REGULA-ED WRY I-I_.-I Performance IIIRQ;\I At low frequencies, where the greatest power output is needed to overcome 1 II speaker -system inefficiency, the per- ß 1G II formance of this amplifier is outstand- owtA1W II ing. Figure 2 shows curves of total har- II ill monic distortion versus power output to 11 rowuAAalral raouErcrRESroysE I an 8 -ohm load at 10,500, and 10,000 cps Ill when using a ' II regulated power supply. At 10 cps the distortion is less than 0.01

1 10 100 1000 10 K per 20 1 K cent at the full watts output and I1IEOUENCY iw CYCLES PEN SECOND at 500 cps only 0.014 per cent. Due to the limitation in the rate at Fig. 4. Power amplifier maximum power output and low -level frequency response. which the power transistor collector cur- rents can be cut off the maximum power current and the total transconductance temperature but in opposite directions output decreases above 10,000 cps. This should be the same. so that they cancel. factor together with the reduction in These conditions are met by establish- Stabilization of the feedback is ac- feedback for stability reasons to only 18 ing the operating points and gains by complished at high frequencies by means db at 20 kc results in a total harmonic means of local feedback. Emitter degen- of local feedback paths from the output content between 0.5 and 2 per cent on eration stabilizes the voltage gain of Q, through small capacitors to the base J 10,000 -cps signals up to 10 watts output. at 1.8 and that of Q, at 2.2. Local feed- circuits of Q, and and from the col- Q Since less power output is needed at the back developed by the collector current high frequencies in normal reproduction, of Q across a 1 -ohm resistor in series and the principal harmonic content is with the emitter of Q, stabilizes the com- beyond the range of audibility, the in- bined three -stage transconductance of creased distortion is of no consequence. Q Q, and at 0.83 amperes per volt. Q Fig. 5. Left: Overloaded power -amplifier Maximum power output at the clip- The total transconductance referred to output at 1000 cps. Right: output vs. in- ping level as a function of frequency is the emitter of Q, is then 1.5 amperes per put under the some conditions. shown by the upper solid line in Fig. 4 volt, resulting in a voltage gain of 12 to when using a regulated supply. an 8 -ohm load. Similarly local feedback lector of Q, to the base of Q,. Shunt Slightly capacitors less output, shown by the dotted curve, is developed by the emitter current of Q1, provide phase lead in the main obtained when using battery power be- across a 1 -ohm resistor in series with the feedback network to help stability. cause the voltage decreases at high cur- emitter of Q10 (and the small base -to- Four 1.3 -volt flashlight -size mercury rents. A pair of 4000- microfarad energy emitter voltage of Q1,) stabilizes the cells power Q Q10, and Q,,. To prevent storage capacitors tends to hold up the three -stage transconductance of Q,,, Q battery voltage during current peaks, and Q at 0.68 amperes per volt. Re- permitting sustained sinusoidal outputs ferred to the emitter of Q also de- Q of 19 watts above 40 cps and instantane- livers 1.5 amperes per volt. A 500 -ohm Fig. 6. Power -amplifier square -wave re- ous peaks of 42 watts when reproducing adjustment in series with the emitter of sponse music and speech. Qe permits precise matching of these transconductances. a condition during the application of When overloaded the amplifier clips power in which both output transistors cleanly and synunrtrically in Fig. 5 Because of the low voltage gain the as are conducting heavily a latching relay and recovers to its normal low normal tendency toward a simultaneous distortion Kl, modified for make before break op- within 30 µsec increase in the two output -stage state after the input sig- collec- eration, turns on the bias voltages tor currents with increased temperature before nal is reduced below the overload point. the high voltages. The relay can be The residual delay in the recovery seems is minimized. Residual drift is compen- sated to within ± 10 ma for ambient tem- peratures of 32° to 120° F by means of diodes and a thermistor which vary the bias on Q, and Qe. These diodes also form part of a network used to change the bias in accordance with battery volt- age variations so as to maintain constant the output -stage no- signal collector cur- rent as either the + 22.5 volts or the - 22.5 volts decreases to as low as 12 volts. Drift of the output voltage due to un- balance in the collector currents of Q,, Fig. 7. Battery - and Q is prevented by additional over- powered control unit has phono all feedback amounting to 57 db at audio preamplifier, four frequencies and 87 db at d.c. This feed- channel mixer, back from the output J to the base of and tone controls. Q, holds the output signal at nearly the base potential of the first stage. The base potential is in turn determined by the very small base -to- emitter voltage of Q, plus that in Q both of which vary with

AUDIO AUGUST, 1959 23 300 k ohms at the RADIO input, 10 mv rms into 320 ohms for 10 cm /sec re- corded velocity at the PHONO input, and 10 mv rms into 1000 ohms at the Mloro- phone input. The Microphone input will accommodate dynamic microphones hav- ing an impedance of 30 ohms or higher. Full output from the power amplifier is obtained when the master VOLUME con- trol is turned 18 db below maximum. Connections for the four inputs, TAPE OUTPUT, main OUTPUT, and power ampli- fier remote control cable are on the side of the control unit. An additional con- Fig. 8. Inside the tone -control preamplifier. nector allows a check on the battery condition without opening the case. to be inherent in feedback circuits that the tape - while recording'; an ON-OFF is minimized by making the switch, and ON -OFF push- buttons for re- saturate and Feedback Circuitry high- frequency loop gain high. mote control of the power amplifier. The At low levels the frequency response PHONO input has a low -noise preampli- Three separate direct -coupled feed- shown by the lower curve in Fig. 4 is fier designed for ESL low- impedance back amplifiers constitute the tone con- flat within 1 db from 10 to 70,000 cps. cartridges. When the tone controls are trol preamplifier shown schematically in The corresponding square -wave re- set at their flat positions the output to Fig. 9. By powering each amplifier from power is equalized to com- sponse, Fig. 6, indicates low phase shift the amplifier its own positive and negative 4 -volt sys- and freedom from ringing. plement the response of the speaker batteries, decoupling problems and tem while the output for tape recording power -line noises are eliminated. Each on all Tone-Control Preamplifier is flat. The tone controls operate amplifier has from 30 to 60 db of feed- channels except MONITOR. The normal The 7 and 8, oper- back around its output stage over the control unit, Figs. signal level at the TAPE OUTPUT is 0.3 range of 20 to 20,000 cps to hold its ates from six self contained 4 -volt mer- volts rms and at the main OUTPUT is 1 cury batteries having a life of 1000 volt rms. Each output has 100 ohms in- distortion to a low value. hours. It provides complete facilities for ternal impedance and is capable of feed- The first amplifier section is a three - single -channel reproduction: a four ing loads of 3300 ohms or higher through transistor phono preamplifier, Q Q =, channel mixer for TAPE, RADIO, PHONO, as much as 1000 feet of cable. Noise and and Q, providing gain and RIAA equal- and dynamic Microphone; a master VOL- distortion are extremely low. ization for the magnetic pickup. Wide - UME control; BASS and TREBLE compen- Input levels are: 1 volt rms into 50 k band low -leakage r.f: type transistors are sators; a MONITOR control for monitoring ohms at the TAPE input, 3 volts rms into (Continued on page 58)

DIO 150K 150K

TI°""I ,... 100 LOG MIC 470 .r.rov

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uc>.--- A t 4+ 4.Alb 4 `+

PHONO tt

MOMEE u BASS ,AR ONMI <»l PUSH SWITCHES Ill ON l: 15 NOR: ALL KESISTOKS t} WATT 5% .13E UNLESS OTHERWISE SPECIFIED.

DENOTES CLOCKWISE POSITION OF

Fig. 9. Tone -control preamplifier schematic.

AUGUST, 1959 24 AUDIO Rockbar introduces a remarkable new 4 -speed Collaro transcription stereo changer - The Constellation, Model TC -99. The TC -99 offers tested and proven professional turn- table performance with the advantages of automatic operation - truly a complete record player for the connoisseur. Here are some of the features which make this the outstanding changer

on the market today : Performance specifications exceed NARTB standards for wow, flutter and rumble Extra-heavy, die cast non -magnetic turntable weighs 6%2 lbs. Extra -heavy duty pre- cision- balanced and shielded four pole motor New two -piece stereo transcription type tone arm Detachable five terminal plug -in head shell Each model is laboratory checked and comes with its own lab specification sheet. Flutter is guaranteed not to exceed .04 %. Wow is guaranteed not to exceed .15%. Rumble is guaranteed down -50 db (at 120 cps relative to 5 cm/sec at 1 KC). The extra -heavy weight turntable is a truly unique feature in a changer. This extra weight is carefully distrib- uted for flywheel effect and smooth, constant rotation. The non-magnetic turntable provides a reduction in magnetic hum pick -up of 10 db compared with the usual steel turntable. The heavy duty four pole motor is precision- balanced and screened with triple interleaved shields to provide an additional 25 db reduction in magnetic hum pick -up. The rotor of the four pole motor is specially manufactured and after grinding, is dynamically balanced to zero. While this is basically a turntable for transcription performance, a fully automatic intermix changer, similar to the mechanism employed in the famous COLLARO CONTINEN-

TAL, MODEL TSC -840, is an integral part of the unit. ADDITIONAL FEATURES : New two -piece stereo transcription type tone arm with detachable five terminal plug -in head shell. This new arm is spring damped and dynamically counterbalanced to permit the last record to be played with the same low stylus pressure as the first. Between the top and bottom of a stack of records there is a difference of less than a gram in tracking pressure -compared with four to eight grams on conventional changers. Vertical and horizontal friction are reduced to the lowest possible level. These qualities -found complete only in Collaro transcription changers -insure better performance and longer life for your precious records and expensive styli. The TC -99 handles 7", 10" and 12" records -in any order. The changer is completely jam - proof and will change or play records at all four speeds. The manual switch converts the changer into a transcription type turntable providing transcription performance_ for the playing of a single long -play stereo or monophonic record. The two -piece arm can then be set down to play portions out of rotation or the entire record can be played singly and sequentially. The double muting switch provides absolute silence for both stereo channels during the change cycle and the R/C network helps to squelch "pop," "clicks" and other noises. The TC -99 comes complete with two audio cables ready to be plugged into your stereo sys-

tem. It is pre -wired for easy installation ; styled in a handsome two -tone ebony color scheme to fit any decor; tropicalizecl against adverse weather and humidity conditions. Long service life is assured by the automatic disengagement of the idler wheel preventing development of bumps and wow. Price of the TC -99 is $59.50, exclusive of the base. All prices are slightly higher in the West. For free colorful catalog on the complete line of Collaro Stereo Changers write Rockbar Corporation, Dept. 100, Mamaroneck, N.Y. The last word in a Transcription Stereo Changer.. .

Collaro Constellation, TC -99

RC12 Hi -Fi Speaker Enclosure Damping Materials

JAMES A. HUFF, JR.`°

A report on a series of tests made to compare relative perform- ance of three types of damping materials in speaker cabinets.

TREIRENIOLS GROWTH in the produc- The action of a speaker is similar to length of these standing waves is a tion of high fidelity equipment has a piston. Air entrapped in the enclosure multiple or sub -multiple of one of the accentuated the need for more in- is actually compressed and expanded as cabinet dimensions, resonances occur. formation on speaker-enclosure damping the speaker cone moves in and out. As It follows that the presence of stand- materials. Cabinet damping techniques this expansion and compression of air ing waves causes a varying acoustical vary widely. Materials recommended for takes place, sound pressure is varied impedance or load to be presented to this purpose range from brick and sand inside the cabinet. the speaker. When this happens peaks to a wide variety of fabricated products This sound pressure is transmitted and dips in the speaker output result. used in the building industry. to .the cabinet walls. When they are Many solutions have been offered to For the manufacturer who wishes to thin or unbraced, they act as diaphragms correct these conditions. The damping select a damping material there is and transmit sound into the room. Cab- of cabinets or enclosures with an acous- limited information. On the other hand, inet radiation also causes dips and peaks tical material has proved the most prac- tone -conscious hi -fi enthusiasts, alert to in the speaker output and adds colora- tical. Such a material should have two the refinements possible in their sets, tion to the sound. properties-high absorption, and low are often frustrated in their attempts Application inside the cabinet of sound transmission. to achieve cleaner sound. damping materials with low sound - Three materials recommended for Throughout the industry, millions of transmission properties minimizes the their sound- absorbing properties were dollars have been spent in laboratory diaphragm action of the cabinet walls. subjected to performance tests. Their research on amplifiers, preamps, turn- relative sound- absorption and sound - tables, pickups, speakers and enclosures. Resonances and Standing Waves transmission performances are com- Results of this research have made top - pared in this report. The materials There are two types of cabinet reso- quality components available to the con- tested were: nance that occur whenever a speaker is sumer, each especially designed for the enclosed in a cabinet. They are funda- 1. Audiofelt, wool felt, 3/8 -inch hi -fi market. mental resonance and spurious reso- thickness (non -woven) The speaker system still remains, nance. 2. Fibrous glass 1 -inch thickness weak link in hi -fi installa- however, the Fundamental resonance is determined (non -woven batt) tions. This is due in large part to the by the compliance of the cabinet, to- 3. Cellulose fiber 21/2 -inch thickness damping materials inside the fact that gether with the compliance of the (asphalt -impregnated sheet) cabinet have been given too little at- speaker. The bigger the volume the tention. The equipment used for the tests con- lower the fundamental resonant fre- look present damping sisted of : A critical at quency for a given speaker. materials therefore is in order. This re- Spurious resonances occur at fre- Bozak 207 -A speaker system port is a step toward examining, com- quencies whose wavelengths are a multi- -watt developing data on three Langevin 128 -A 20 amplifier paring, and ple or submultiple of the cabinet dimen- damping materials having good acous- Magnecorder Model PT6 -BA2HZ tape sions. tical properties. recorder Whenever sound waves are generated Capps condenser microphones, Model Cabinets and Damping within an enclosure they travel outward CM -2030C from the source (the loudspeaker cone), RCA wideband oscilloscope, Model the back of a speaker Sound from strike a wall, and are reflected. This re- WO-78A out of phase with the cone is 180 deg. flected or "bouncing" wave action con- Radio Model 1302 -A audio Under certain General sound from the front. tinues until the energy in the wave is oscillator conditions of path length (front to dissipated and the wave dies out. The back) and frequency they will cancel. time it takes for this sound energy to be Test Procedure This cancellation causes dips and peaks expended depends on the absorption in the speaker output. By mounting the properties of the reflecting walls. For all the tests the saine amplifier speaker in a cabinet, however, the back Hard surfaces, such as wood, absorb and speaker were used. The speaker wave is confined within the enclosure little energy and are highly reflective. cabinet was approximately 11 cubic and cancellation cannot occur. It takes a comparatively long time, feet. The tests were made with the At the same time, enclosing the therefore, for sound waves generated in- cellulose, fibrous glass, and felt ma- speaker in a cabinet poses problems of side a wood cabinet to die out. terials in that order. Constant input cabinet radiation, cabinet resonances Sound waves built up inside a cabinet power was maintained to the speaker and standing waves. or enclosure in this manner are re- for all the tests. Sound Absorption Tests: These tests 339 Twin Lane So., Wantagh, N.Y. ferred to as standing waves. If the AUDIO AUGUST, 1959 26 7 Improve speaker performance

Felt Laboratory tests conclusively prove FELT is the most effective damping material for hi -fi speaker enclosures!

In recent tests made with the usual damping materials (fibrous glass and cellulose fiber), FELT was scientifically proven to be the only material really effective in the low- frequency range where trouble- some cabinet resonances occur and where most of the power is transmitted. Continental The use of FELT resulted in a smoother power output over the entire BRAND frequency range from 50 to 15,000 cps, and acoustical power output from the speaker was increased from 25 to 50 per cent in the low- and middle- frequency range. Listening tests prove without doubt, FELT that sound from a cabinet lined with FELT has a cleaner sound with a much better balance between the highs and lows. "HI -FI FELT" only $5.98 per sq. yd. (packaged)

At better stores everywhere or write to : CONTINENTAL FELT CO., 22 West 15th Street, New York 11, N.Y.

"STUDIO QUALITY RECEPTION" for your Hi -Fi Room! Continental's new DECOR-FELT WALL COVERING - with the quiet dimension for distinctive interiors - eliminates unpleasant sounds- enhances tonal qual- ity -turns acoustical problems into beauty spots. FREE color swatch folder on request! AUDIO AUGUST, 1959 27 were made to determine which of the three materials had the best sound absorbing properties. The speaker cab- inet was lined with each material. All the inside surfaces were covered with the exception of the front panel. A microphone was placed inside the speaker cabinet. This microphone was used to measure the sound pressures for selected frequencies between 50 and 15,000 cps. This is the range of fre- quencies encountered in hi -fi repro- (A) (B) (C) duction. Since damping materials are traces made during the Sound Absorption Tests. (A), cellulose in- Fig. 1. Oscilloscope used to reduce the sound pressure material; (B), fibrous glass material; and (C), felt. The traces show sound pressures side the cabinet, their effectiveness is inside the speaker cabinet for a frequency of 50 cps. readily determined by measuring this sound pressure. The lower the sound pressure inside the cabinet the more Summary of Results the three materials at various frequen- effective the damping material. cies. Figures 1 through 3 are photographs Sound Transmission Tests: These Figure 6 shows the results of the traces made during the tests were made to determine which of of oscilloscope Speaker Output Tests. The output of Figure 1 shows the three damping materials transmitted Sound Absorption tests. the speaker, measured in decibels, is inside the speaker the least sound. This property is im- the sound pressures plotted vs. frequency for felt, and the of 50 cps, Fig. portant in order to prevent the sound cabinet for a frequency three materials. 1000 cps, and Fig. 3 inside the cabinet from reaching the 2 the same data for each case, (A) repre- Discussion walls with sufficient amplitude to set for 15,000 cps. In material, (B) the A good damping material has two them vibrating. Cabinet vibration is sents the cellulose undesirable since it is out of phase with the front radiation from the speaker and can cause a power loss of as much as 50 per cent, which is especially noticeable at the low frequencies. The transmission tests were conducted by placing each material between the speaker and the microphone and re- cording the sound pressure drop in db. The tests were made at selected fre- quencies between 50 and 15,000 cps. this series (C) Speaker Output Tests: For (A) (B) of tests a second microphone was placed sound pressures inside the speaker cabinet at on the axis of the loudspeaker. This Fig. 2. Oscilloscope traces showing 1000 cps. (A), cellulose; (B), fibrous glass; and (C), felt. microphone measured the output of the speaker for selected frequencies between 50 and 15,000 cps. Since the same fre- fibrous glass material, and (C) the felt important properties -high absorption quencies and same power input to the material. and low sound transmission. High ab- speaker were used for all three ma- Figure 4 shows the relative sound sorption is necessary to prevent the re- Low terials, it was easy to see the effect the pressure in decibels vs. frequency for the flection of sound inside the cabinet. to pre- different damping materials had on the three materials. The sound pressure was sound transmission is necessary sound inside the speaker output. By examining the curves measured inside the cabinet and the vent the undamped cabinet from reaching the cabinet walls plotted from these tests it was possible curves plotted from data gathered dur- Tests. Figure with sufficient amplitude to cause them to determine which damping material ing the Sound Absorption the results of the Sound Trans- to vibrate. If these two conditions are gave the smoothest output over the fre- 5 shows mission Tests. The curves show the drop not met, standing waves result and quency range and which gave the high- in sound pressure, in decibels, through spurious cabinet resonances occur. When est power output. All sound pressures were measured in db. The data from these tests were plotted and are shown in the DATA section of this report. Dur- ing the sound absorption tests, oscil- loscope pictures were taken of the sound waves inside the cabinet. These pictures plainly show the differences between the three materials. Listening Tests: As each material was tested, listening tests were made to determine the differences in sound (B) (C) caused by these materials. Various (A) at musical selections were played through Fig. 3. Oscilloscope traces showing sound pressures inside the speaker cabinet the system and recorded on tape. 15,000 cps. (A), cellulose; (B), fibrous glass; and (C), felt. AUDIO AUGUST, 1959 28 the all -new VR -22

VR -225 .5 mil diamond stylus. For pro fessional -typestir' tone arms, $27.95. stereo. cartridge

VR -227 .7 mil diamond stylus. For record changer or turntable, $24.95.

Now, outstanding in all four critical areas of stereo cartridge performance Compliance- Tracks precisely, not a trace of stiffness. Channel Separation -Up to 30 db for maximum stereo effect. Nothing higher on the market! Response -Smooth and flat for superior sound from 20 to 20,000 cycles (VR -225), 20 to 17,000 cycles (VR -227). Virtually hum -free -triple shielded against stray currents. This is our masterpiece. We urge you to hear it.

GENERAL ELECTRIC

Audio Components Section, Auburn, N. Y.

AUDIO AUGUST, 1959 29 tive over the entire range than either of 10 1 1 1 1 1 1 1 I I 1 1 1 1 1 1 1 the other materials. FIBROUS GLASS (I" THICKNESS) -- An examination of Fig. 5 shows the O `k - - -- CELLULOSE (21/2" THICKNESS) - sound loss through the three materials. Fibrous glass was wholly ineffective, `\ FELT (3/8" THICKNESS) - s -10 ....\ having practically no transmission loss Fig. 4. Curves of below 500 cps, and only 3 db at the _. relative s o u n d higher frequencies. This meant that any pressure vs. fre- undamped sound inside the cabinet o e. quency as meas- would be transmitted to the cabinet o v/ ured inside the walls. o -00 iO speaker cabinet. The cellulose material was effective above 500 cps, but this is not as im- -40 portant as it would seem. If we refer again to Fig. 4, we see that due to the .high absorption of all the materials at 20 ]0000 100 1000 ' 10000 the higher frequencies there is very little FREQUENCY IN CYCLES PER SECOND sound pressure inside the cabinet. There- fore, the real need is for low transmis- this happens a general lack of clarity tain most of the power and any loss sion and high absorption in the loty- in the sound results, and the power in this range is very noticeable. Further- frequency range. Felt is 50 to 75 per output of the speaker is lowered. more, most of the trouble from cabinet cent more effective in this range than An examination of Figs. 1 through 6 resonances occurs in this range. either of the other two materials. shows the of over cellu- On an average, felt was found to be superiority felt The results from these tests would lose and fibrous glass in absorbing prop- 50 per cent more effective in damping indicate that the use of felt should ac- erties. Felt is particularly effective in throughout the entire frequency range complish two things with regard to the the low frequencies. Referring to Fig. from 50 to 15,000 cps. sound output from the speaker : (1),

10 the speaker output in the low and mid- dle frequencies should be higher, and (2), speaker output should be smoother. o This is actually what happened as an examination of the curves of Fig. 6 will -10 show. These curves were plotted for z Fig. 5. Curves of specific frequencies, 50, 100, 300, 500, drop in sound 1000, 3000, 5000, 10,000, and 15,000 cps. 20 -_, pressure through The acoustical power output of the the three damp- speaker was smoother and was 25 to 50 z -3o ing materials. per cent greater with the use of felt. The O FIBROUS GLASS I" THICKNESS) --- fact that the use of felt causes the re- -40 - -- -- CELLULOSE (2 Y2 ' THICKNESS) sponse to be smoother is very important, FELT (3/8" THICKNESS) particularly in the high-frequency range.

11 1 1 1 1 1 1 1 1 1 111111 A lack of smoothness in this range 20 . ,0000 100 WOO 10000 causes the FREQUENCY IN CYCLES PER SECOND sound to have a very un- pleasant "edge" or "sharpness." 4, we see that in the low frequency range It should be pointed out that a thick- from 50 to 300 cps, the sound pressure ness of only % in. was used for felt Conclusion inside the cabinet lined with felt was 3 against 21/2 in. for the cellulose and 1 Felt was found to be a superior damp- to 6 db lower than for the other mate- in. for the fibrous glass materials. material. The possibilities for rials. This means that felt was 50 to 75 During the transmission tests a ing per cent more effective in damping the double th'ckness of felt was also tried. further development work that would low frequencies. This is an important It was found that the transmission loss lead to an ideal damping material are point, for the low frequencies con- was doubled, making it far more effec- very exciting. Felt was the only material really 10 effective in the low- frequency range where troublesome cabinet resonances occur and where most of the power is o transmitted. The use of felt resulted in a smoother z power output over the entire frequency Fig. 6 Curves the showing relative range from 50 to 15,000 cps, and n 20 acoustic o u t p u t acoustical power output from the r. from the three en- speaker was increased from 25 to 50 0 closures. low- middle -fre- 2: 30 per cent in the and O (1" THICKNESS) quency range. - - -- FIBROUS GLASS Listening tests confirmed the results -40.- CELLULOSE (21/2" THICKNESS) - - -- of the above. The sound from the cab- - FELT (3 4" THICKNESS) inet lined with felt was a cleaner sound

I I I I I I I I e e 1 1 1 1 1 1 1 . ' ...... " . . MOW a much better balance between the MD ,000 10000 with FREQUENCY IN CYCLES PER SECOND highs and lows.

AUGUST, 1959 30 AUDIO Combining the performance of costly electrical crossover multi -way speakers and the economy of single cone speakers, you have a wide range of selection, ranging from a handy 61" two -way model up to a 12v threeway model.

The PIONEER PIM -1ÓA, PIM -20A and PIM -25A speakers hove two cones actuated by a single voice coil and magnet assembly. Low frequency signals are reproduced by the large outer cone, while high frequency signals ore reproduced by the small inner cone. The PIM -30A has two cones actuated by a single voice coil and magnetic assembly for low frequency and mid -range reproduction, and an independent high frequency tweeter unit for high frequency reproduction. Due to the mechanical filters furnished on the large outer cone, the directional characteristic is improved vastly in compared with the double -cone speakers mode hitherto and intermodulation distortion in thus minimized and therefore, smooth overall response is provided at low cost.

FUKUIN ELECTRIC, TOKYO, JAPAN 5 OTOWACHO 6- CHOME, BUNKYO -KU, TOKYO.

AUDIO AUGUST, 1959 31 What to Look for in a Tap e Recorder

HERMAN BURSTEIN

THE PRECEDING THREE ARTICLES have dealt with some basic matters that the audiofan will wish to consider in Fig. 2. A stereo purchasing a tape machine : whether to tape machine util- buy a transport only or a transport and izing a plug -in at- electronics; how many heads the machine tachment for re- should have; what kind of record level cording second indicator is suitable for his purposes. channel. (Tand- The present article deals with additional berg) Unit at the varying degrees of impor- left is the auxil- factors, of iary recording am- a purchase de- tance, that play a part in plifier for the sec- cision. Some of these concern electrical ond channel; with- performance, some mechanical perform- out it, the machine plays stereophon- 2S0 Twin Lane E, Wantagh, N. Y. t ically and records monophonically.

anee, and others operating convenience. chine by replacing the mono playback Probably no one machine contains all head with a stereo head, but this calls the features that may be desired by all for an additional playback amplifier, audiofans. On the other hand, needs vary raising two problems : (1) that of closely from one tape recordist to another. matched equalization and amplification Through a preliminary familiarity with facilities in the playback amplifier for the features available in one machine or each channel; (2) that of a cable run to another, the audiofan is in a position to the additional amplifier, with high fre- is choose that tape recorder which is most quency losses taking place if the cable likely to satisfy both his wants and his too long, and with the possibility of hum budget. pickup if the cable is iníproperly routed. A number of tape machines now pro- Stereo Versus Mono vide for stereo playback but only mono 1. the In view of the pace of stereo, the indi- record, as illustrated in Fig. If eventually vidual who purchases a tape machine for audiofan has any thoughts of he serious music listening is well advised to wanting to record stereophonically, for stereo at least should inquire whether such a machine with provision for consider one equipped Fig. 1. A tape machine mode. Of course it is has facilities for properly adding a re- monophonic record- in the playback stereo payback and monophonic ma- cord amplifier. The second channel re- ing. (Norelco) possible to modify a AUDIO AUGUST, 1959 32 AMPEX 960 STEREOPHONIC RECORDER/ REPRODUCER

ABOVE --960 PORTABLE STEREO RECORDER /REPRODUCER BELOW -MODEL 2560 PORTABLE Stereo STEREO SYSTEM CONSISTING OF 960 AND PAIR OF 2010 Portable A MPLI FIERSPEAKERS PLUS! Guiding the Ampex engineers who created the 960 was a dual objective - that of building a machine which was not only a superb example of engineering skill, but one which would also offer its user a range of capabilities far exceeding that of any other recorder made today. The result was not merely an improved stereo recorder, but an entirely new concept in home . The STEREO 960 fits into family life in literally dozens of ways, contributing many tangible benefits in musical, educational and recreational fun. You'll use it to keep up the family correspondence by sending "letters in sound ", to tape stereo programs off the air, to preserve your best monaural and stereo discs on tape, and to acquire new musical and language skills. You'll have endless fun exploring the 960's many fascinating recording capabilities, including sound -on- sound, echo chamber effects, and other advanced techniques.

AMPEX STEREO SIGNATURE OF PERFECTION IN SOUND Relax and enjoy the show - let your Ampex do the narration! With the RECORDER /REPRODUCER commentary on tape, your color slide shows are more SPECIFICATIONS professional, more complete, and more fun!

The true values of a recorder are best assessed through careful evaluation of its performance specifi- Your favorite LP's and Stereo cations and operating features. It is worthwhile noting here that these specifications are based not on Discs are at their exciting theoretical design parameters but on actual performance tests. They are specifications which the best while they're new and recorder not only meets or exceeds today, but which years from now will still hold true. unscratched. That's when to The Ampex Model 960 Stereophonic Recorder Reproducer is capable of essentially distortionless tape them on your Ampex, frequency response from 30 to 20,000 cycles per second at the operating speed of 7V2 inches per and preserve their original second, and from 30 to 15,000 cycles per second at 334 inches per second. Its precision -engineered quality for keeps! timing accuracy is such that it offers perfection of pitch held to tolerances of less than one -third of a half -tone. Playing times, using standard 1.002 "), long play (.0015 "), and extra -long play (.001") tapes are as follows: When you tape it "off the (a) 4 -Track (b) 2 -Track (c) Monaural Tapes, air" your only cost is for Stereo Tapes Stereo Tapes half -track blank tape. Yet your musical

200 foot reel 33/4 ips - 2 hrs. 8 min. 33/4 ips - 1 hr. 4 min. 33.4 ips - 2 hrs. 8 min. repertoire can soon equal 71/2 ips 1 hr 4 min. 71/2 ips - 32 minutesnutes 71/2 ips - I hr 4 min. that of all the stations 800 Foot reel 33/4 ips - 3 hrs. 12 min. 34/4 ips - I hr. 36 min. 33/4 ips - 3 hrs. 12 min you hear!

7' /z ips - 1 hr 36 min. 71/2 ips - 48 minutes 71/2 ips I hr 36 min.

!400 fool reel 33/4 ips - 4 hrs. 16 min. 33 ips - 2 hrs. 8 min. 33/4 ips - 4 hrs. 16 min

71/2 ips - 2 hrs. 8 min. 71/2 ips - 1 hr. 4 min. 71/2 ips 2 hrs. 8 min. There's a real future in family your RECORD INPUTS: High impedance line inputs (radio TV phono, auxiliary) 0.3V rms for program level; fun like this -with high impedance microphone inputs Ampex you can live such happy moments over and PLAYBACK OUTPUTS: Approximately 0.5V rms from cathode follower when playing program level tapes over again, with a quality so PLAYBACK FREQUENCY RESPONSE: 30- 20,000 cps at 71/2 ips; 30. 15,000 cps at 33/4 ips lifelike you're almost literally Within +2 db 50- 15,000 cps at 71/2 ips, 55 db dynamic range carried back. Within ±2 db 50- 10,000 cps at 33/4 ips, 50 db dynamic range

FLUTTER AND WOW: Under 0.2% rms at 71/2 ips; under 0.25% rms at 33/4 ips In the Ampex "Speech Testing HEADS: Manufactured to the same standards of precision that exist in Ampex broadcast and recording Game", you pit your wits studio equipment. Surfaces are lapped to an optical flatness so precise that they reflect specified against the trigger -quick wavelengths of light, resulting in uniform performance characteristics and greatly minimizing the memory of the Ampex effects of head wear. Azimuth alignment of stereo head gaps in the same stack is held within 20 recorder /reproducer. You seconds of arc, equivalent to less than 10 millionths of an inch - a degree of precision achieved can't win, but it's fun trying. through use of a unique process involving micro -accurate optical measurements within a controlled environment. Head gap width is 90 millionths of an inch +5 millionths of an inch.

Letter- writing is no longer a problem, with on Ampex in the house ... now it's a family project. And even KEY TO THE EXCITING FUN FEATURES OF THE 960 -- more fun than sending letters THE AMPEX STEREO -GRAPH in sound is receiving them!

Here's the simplest, quickest answer For "letters in sound ", the to almost every question about how to 3" tape reel holds as much perform the operations illustrated at as a 10 -page letter, mails first class anywhere in the right and numerous other recording United States for 8c. functions. The Ampex Stereo -Graph shows you, quickly and clearly, the proper dial settings to make for more than a dozen of the most popular uses and other special effects. A convenient for the 960 ... including sound -on- tape footage /playing time indicator is sound, language and music instruction, included on the reverse side.

MODEL 2010 The Ampex, in private MATCHING rehearsal, can be a wonderful AMPLIFIER -SPEAKER confidence- builder for people who normally develop The Ampex Model 2010's ten -watt (20 watts peak) ampli- rubber knees when faced fier section provides operating characteristics (unequalized) with the prospect of speaking before a group. flat within ' 0.1 db, with total harmonic distortion less than 0.5 of 1 %, throughout the maximum range of human hearing , at rated output. Noise and hum ore 80 db Learning to speak a new below rated output, and input sensitivity is 0.18V to language is made develop rated power. immeasureably easier on The specially designed 8" speaker provides smooth, peak - the Ampex; you can record free response throughout a remarkably wide audio range. your own phrases side -by -side Such superior design features as its massive die -cast frame with those of the instructor, and edgewise -wound ribbon coil contribute effectively to and play them back for higher levels of performance than ever before achieved comparison at any time. with a speaker this size. When you strike up the band in stereo, you don't need MODEL 960 DIMENSIONS: Portable cases 9" x 15" x 171/2". Unmounted recorder professional musicians to 13" x 15" x 616" depth below top plate, 1%" above. Recorder weight 36 lbs., make a professional speaker amplifier 31 lbs. recording. Advanced techniques are amazingly AMPEX AUDIO. INC. SUNNYVALE. CALIFORNIA HANS easy on the Ampex. cord amplifier should have the same to noise ratio. This does not mean that equalization and gain as for the other 3.75 -ips tapes are yet as good as 7.5 -ips channel, and -very important-there ones of recent vintage. However, they should be means for synchronizing the are already as good as the 7.5 ips tapes bias oscillators in the two amplifiers, if of several years ago, and it can be ex- separate oscillators STEREO are used, so that they pected that technological progress will will operate at the same frequency. Bias bring further improvement. current in each channel will to some de- Accordingly, the serious audiofan may gree leak through to the other channel. wish to include the 3.75 -ips speed and to ON If the two currents are of different fre- make sure that the machine he purchases quency, they will beat together, and the does all that is possible in the present resulting beat frequencies will appear on state of the art to achieve maximum per- DISPLAY the tape, causing birdies and other ob- formance at this speed. Specifically, he jectionable sounds. Figure 2 shows a will want a machine with a playback tape recorder designed to permit addi- bead that has a gap of .0001" or less, at the tion of a second record amplifier; in this and having the recording equalization case the oscillator of the first channel and bias current that allow frequency Detroit Third Annual also serves the second channel. response to extend to 10,000 cps and be- yond. On the other hand, since equaliza- Tape Speeds tion and bias current requirements will he different For home purposes, in the past few at the 7.5 -ips speed, he will HIGH want to make years the virtually standard speed com- sure that performance at this higher patible with high fidelity has been 7.5 speed is not compromised by failure of the machine ips, which permits frequency response to to change the bias FIDELITY and equalization about 15,000 cps and at the same time when the tape speed is switched allows satisfactorily low distortion and to 7.5 ips. The a satisfactorily high signal -to -noise ratio. audiofan will probably find that SHOW The 3.75 -ips speed has also been that 3.75 -ips speed is quite suitable for widely various used, although not considered compatible types of program material not THREE FULL DAYS of the highest with high fidelity. The principle diffi- fidelity, such as old records OF CONTINUOUS one culty at the lower speed lay in high -fre- wishes to copy (in fact, the loss of the higher DEMONSTRATIONS quency response. All other things re- frequencies can be a distinct blessing maining equal, the frequency response of in this situation since these fre- a tape machine varies directly with tape quencies will consist more of noise than STATLER HOTEL music), speed. Thus a machine capable of main- AM station programs, etc. Or there FRIDAY, SATURDAY, taining flat response to, say, 12,000 cps may be situations where one is willing at 7.5 ips (response may be 3 to 6 db to exchange some sacrifice in AND SUNDAY, down at 15,000 cps) will be able to main- quality for the privilege of doubling the recording OCTOBER 16 -17 -18 tain fiat response only to 6,000 cps time on a reel tape. Thus in at taping 3.75 ips. an opera or other lengthy work, FROM 1 P.M. to 10 P.M. The problem at 3.75 ips occurs in large one can get from two to four hours of time part in playback. being due to the fact on a 7 -inch reel, using half -track monophonic the newest and latest in stereo that treble response varies inversely with recording or quarter -track stereo high fidelity from leading width of the playback head gap. The re- recording. Regular tape will yield high fidelity cent introduction of heads with ex- two hours, long -playing tape three hours, manufacturers tremely narrow gaps -as fine as .00009" and extra -long -playing tape four hours. For non -high -has made it possible to extend fre- -fidelity applications, Don't miss this ex- quency response such as recording speech, dance to about 15,000 cps at music hibit of hi -fi 3.75 ips so far as playback is concerned. for parties, and so forth, the 1.875 -ips equip- But there are also very serious recording speed is coming into increasing use. In ment . . . from the fact, losses at high frequencies clue to bias this speed now enjoys about the most economical current same status as 3.75 and to the phenomenon known ips formerly occu- units for the budget - pied. A number as self -demagnetization (recorded fre- of tape machines now minded to quencies on offer this speed along with spectacu- the tape are equivalent to a surprisingly lar home music small bar magnets; the higher the fre- satisfactory quality for non -critical uses thea- quency, the smaller is the equivalent where length of playing time is impor- ters ... compare and magnet and the greater is the tendency tant. Thus on a 7 -inch reel of tape one enjoy them all. of the opposite poles of each magnet to can record from four to eight hours of cancel each other). material at 1.875 -ips, depending upon By using somewhat less bias current whether one is using regular, long -play- Complete Stereo and Mono- ing, phonic High Fidelity Systems than at 7.5 ips 1 which reduces treble or extra -long -playing tape. losses), by recording at somewhat lower Amplifiers Pre -Amplifiers levels (which compensates for Frequency Response - - the FM-AM Tuners - Turntables greater distortion because of reduced At 7.5 ips, - a modern tape recorder Record Changers Phono Car- bias), and by using somewhat more should - be able to cover the range of 40 to tridges Microphones Music treble boost in recording, it has been 15,000 - - cps, being no more than 3 or 4 db Control Centers Speakers found possible to put on the tape at 3.75 down - - at either extreme and achieving Speaker Enclosures Equip- ips a signal with frequency response cor- quite flat response- ±2 - responding within ±1 db or ment Cabinets - Finished and at least to minimum high fi- db between 50 and 10,000 delity standards cps. Response Assembled or Do -It- Yourself Kits and having acceptably within ± 3 db may be considered low distortion and acceptably satis- high signal factory, but not of top quality. At 3.75

AUDIO AUGUST, 1959 35 cent II. Many machines, however, state few, some at relatively moderate prices, performance in terms of 3 per cent har- that are the equivalent of professional 9= REAR GAP (CLOSED) monic distortion, and sonic even in ternis machines in this respect. LAMINATED CORE of 5 per cent; these amounts may cor- respond to 30 per cent and more 1M. Quality of Heads the difference between Considering that Audiofans are wont to be very dis- .11111 recording at a level that results in 1 per II criminating about the phono cartridges WINDING I' .I. WINDING cent harmonic distortion and recording they choose for their audio systems. In of 5 per cent har- Alb AN. at a level productive similar fashion, there are quality differ- represents an increase monic distortion ences among tape heads that deserve at- \ of about 8 db in recording level, it can tention. Some of the factors involved in he understood why some manufacturers FRONT GAP (VASTLY íF head quality are as follows: rate their machines on the basis of 5 per ENLARGED) 1. Gap Width. As pointed out before, CONTACTS THE TAPE cent. They are adding 8 db to the signal - the narrower the gap, the better the high - -noise ratio they can claim for their to frequency response in playback. Most Fig. 3. Tape head of laminated construc units. playback heads encountered today have The audiofan desiring truly clean, tion. gaps sufficiently narrow to permit rela- silky recordings-assuming such pro- extend at least to tively flat response throughout the audio ips, response should gram material is available to him -will flat be- range at 7.5 ips and a close approxima- 10,000 cps, remaining reasonably probably not want to operate his ma- 8000 cps. At 1.875 ips, re- tion to such response at 3.75 ips. The gap tween 50 and chine at levels that take him into 5 per 5000 cps may he ex- should be .00025" or smaller for speeds sponse to about cent harmonic distortion. More likely, he pected. of 7.5 ips or higher. It should be .0001" will want to stop at about the 1 or 2 per or smaller for 3.75 ips. cent level. Therefore, a tape recorder Distortion and Signal to Noise Ratio 2. Gap Linearity. Recording of the he rated for signal-to -noise ratio should tape takes place at the trailing edge of The playback amplifier is generally in terms of a signal, in the range of 250 record head gap (the last edge con- the dominant source of noise in a tape the tacted by the moving tape). To achieve reproducing system. The amount of sig- FRONT GAP a well- defined signal on the tape, it is nal produced by the tape playback head (CONTACTS THE (TAPE) necessary that this gap edge be equally is at the most a few millivolts in the CORE PIECE CORE PIECE must be as perfectly audio mid -range and is a fraction of a well defined. It as possible. Sharpness millivolt at low frequencies. When this sharp and straight edge case both edges weak signal undergoes the necessary am- of the gap -in this the edges plification and equalization (bass boost), -is also vital in playback. If WINDING magnetically the noise and hum of the first stage in are rounded, then the gap width the playback amplifier and the hum behaves as though its physical head with a picked up by the head, are also greatly were increased. Thus a may magnified. The more signal on the tape .00025" gap and very linear edges - high- response that is! the higher the recording level provide better frequency - well -de- the greater is the magnitude of the audio than a .00015" head with a less signal relative to playback noise and fined gap. In a high -quality playback hum. In other words, the signal to noise head, the magnetic gap is about 10 per ratio is greater. Unfortunately, as the cent wider than the physical gap. BACK GAP CLOSED bas- recording level is increased, there is also 3. Head Constriction. Heads are an increase in distortion due to the char- ically of two types, laminated and non - then, dis- Fig. 4. Tape head of non -laminated con- laminated, as illustrated in Figs. 3 and acteristics of the tape. In sum, struction. tortion and signal -to -noise ratio go hand 4. The laminated head tends to have in hand; the more distortion one is will- to 500 cps, recorded at a level producing greater output because of its greater ing to tolerate in a tape system, the no more than 1 or 2 per cent harmonic volume of magnetic material. Moreover. is based on a the laminations serve to reduce eddy cur- - higher is the feasible signal -to -noise distortion. If the ratio ratio, assuming that all else remains the higher distortion figure, one can make a rent losses (by interrupting eddy cur- same. rough adjustment by subtracting 2 db rent flow), which increase with fre- It follows that one must define how for each 1 per cent of distortion above quency. much distortion is acceptable. However, 1 per cent level. -Figure 5 shows another type of non - this is not a straightforward problem. To Based on 2 per cent harmonic distor- laminated head, whose gap has consid- begin with, tape distortion is almost in- tion, which is the NARTB (now NAB) erably less depth than in Figs. 3 and 4. variably stated in terms of harmonic standard, a tape recorder may be con- This means that the gap wears more rather than intermodulation distortion, sidered excellent if it achieves a signal - because the amount appears respectably to -noise ratio of about 55 db, and very low in terms of harmonic distortion but good if the ratio is closer to 50 db. Below tends to assume outlandish proportions 50 db begins to get out of the category when stated as intermodulation distor- of high fidelity. Less than 45 db tends to tion. Whether maximum harmonic dis- be unsatisfactory. With a machine hav- tortion should he 1, 2, 3 per cent, or ing a signal -to -noise ratio that ap- possibly more is a viewpoint that varies proaches 55 db, one can make a clean considerably among tape machine man- recording and play it back at life -like ufacturers. levels, yet have virtually no discernible Signal -to -noise ratio of the top quality background noise during quiet passages. machines tends to be rated by their man- Such machines, unfortunately, are still ufacturers on the basis of 1 or 2 per cent much more the exception than the rule of non -laminated maximum harmonic distortion. This may so far as home tape recorders are con- Fig. 5. Another type tape head. correspond roughly to about 5 to 10 per cerned. On the other hand, there are a 6 AUDIO AUGUST, 1959 quickly, with attendant loss of high - frequency response. 4. Hum- Bucking Windings. Whereas the heads in Figs. 3 and 5 each have two sets of windings, the head in Fig. 4 has only one winding. Two windings are de- sirable because this permits connecting them Fig. 7. NARTB in series so as to balance out hum playback and at the same Equali- time increase voltage zation. output. The manner of connection is il- lustrated in Fig. 6. Hum polarity tends to he the same at each output terminal, so that there is little or no hum potential between the terminals. On the other hand, the signal polarity at one terminal is positive when the other is negative. >e 5. Saturation. The core and design of Iaa I_ MOM FREQUENCY IN CYCLES PER SECOND the record head must be such as to per- mit sufficient magnetic flux to be devel- will be apparent as an unsteadiness in diameter of the oped to magnetize the tape, but without capstan may he out of the sound. Flutter will he noticeable as tolerance, resulting in excessive speed saturating the head and thereby causing imparting a grainy or noisy quality to error. Or there may be other misadjust- distortion. While tape heads are gen- the note. erally satisfactory in this respect, the ments. The individual who writer has come across instances where Speed Accuracy pays the extra cost the record head saturated before the tape of a tape machine containing a syn- did. Professional requirements are that chronous motor is entitled to a speed ac- tape speed be correct within ±0.3 per curacy within 0.3 per cent. Should he cent. Since there are 1800 seconds in find, through a test timing tape or use of one half -hour (approximately the play- a tape stroboscope, that the error ex- ing time for one track on a 7 -inch reel ceeds 0.3 per cent, he is entitled to have of standard tape), a 0.3 per cent error this excessive deviation corrected by translates into 5.4 seconds slow or fast whatever means are appropriate, includ- per half hour. Professional machines, ing replacement of the machine. H I. and sometimes the semi -professional ones On the other hand, if the machine does as well, generally achieve an accuracy of not have a synchronous motor, speed er- 0.2 per cent, which is 3.6 seconds slow or rors up to 1 per cent should be expected fast per half -hour. and tolerated. H. H. Over 1 per cent may be S. So long as a tape machine is employed considered excessive for a. high -quality to play only tapes recorded on the same home machine with a non-synchronous H -HUM POLARITY machine, S =AUDIO SIGNAL POLARITY the speed error is of no conse- motor. quence, assuming the error remains the In measuring speed accuracy, this Fig. 6. Connecting the dual windings of same over time. However, if commer- should be done at several portions of the a tape head in series for maximum volt- cially recorded tapes or other tapes made reel, because the error will tend to vary age output and for hum cancellation. on different machines are to be played, from beginning to end of a reel of tape. speed errors Wow and Flutter appreciably greater than While it is desirable for the individual 0.3 per cent, particularly those over 1 to measure speed accuracy (by means of Wow refers to slow variations in per cent, are apt to he noticed as signifi- a stroboscope or test tape), in the great speed, below ten times per second, heard cant deviations from correct pitch. majority of instances there is nothing as a quavering or "sourness" in the fre- The better tape machines employ syn- he personally can do to correct the situa- quency being reproduced. Flutter refers chronous motors, whose speed is essen- tion. Whereas a fair number of phono to rapid variations in speed, up to thou- tially determined by the line frequency, turntables and even record changers pro- sands of times per second, which tend to namely 60 cps. But use of a synchronous vide the operator with means for readily be heard as extraneous sounds in the motor for driving the capstan does not adjusting speed, it is a rare tape re- nature of noise. That is, one hears a fre- in itself guarantee accurate speed. The corder that makes such provision. Before quency corresponding to the rate of fluctuation. Professional performance calls for wow and flutter not to exceed 0.2 per cent, and preferably to be less than 0.1 per cent. This is not very easy to achieve, particularly when tape speed is below 15 ips. One may say, then, that for home Fig. 8. Playback purposes, about 0.25 per cent is the equalization em- maximum amount consistent with high - ployed at 3.75 fidelity performance. ips. The ear is a good instrument for cheek - ing wow and flutter. By playing a test tape having a recorded frequency of about 3000 cycles (or by making such a tape with the aid of an audio oscillator), one can readily determine whether .o wow Ne and flutter ,ewe are unduly offensive. Wow FREQUENCY IN CYCLES PER SECOND

AUDIO AUGUST, 1959 37 obtained directly from a tuner, TV, or the like. The other input is for micro- MIC. RECORD O Im phone. In many cases these are alterna- MICROPHONE PREAMP AMPLIF IER INPUT JACK tive inputs, as illustrated in Fig. 9, so RECORD that one can record from one input or HEAD from the other, but not from both at once. Insertion of a phone plug into the HIGH LEVEL high -level input jack disconnects the INPUT JACK from When phone plug is nserted, the connection microphone signal. In other instances, it preamplifier to the following stage the microphone is from both sources is interrupted. possible to record simultaneously. Too often, however, only -level Fig. 9. Tape machine permitting one to record from a microphone or a high the high -level input has a gain control, source, but not both at once. so that it is difficult to achieve satisfac- tory mixing. In the better machines, PLAYBACK TAPE AMPLIFIER there are individual gain controls for HEAD each input. - VOLTAGE POWER SPFAKER IN The microphone input in the lower AMPLIFIER AMPLIF IER TAPE MACHINE price machines is customarily intended for a piezoelectric (ceramic or crystal) o a high- impedance OUTPUT TO EXTERNAL SPEAKER microphone or for magnetic microphone. If one intends to OUTPUT TO EXTERNAL AMPLIFIER o use a crystal or ceramic microphone, it is necessary to ascertain that the input Fig. 10. Tape machine with separate outputs for external speaker and external am- impedance of the tape recorder is suffi- plifier. ciently high to permit full bass response. of 5 meg- the user seeks to tinker with the trans- each speed because the recording losses Typically, an input impedance port mechanism in order to speed it up vary with tape speed. Therefore the tape ohms or more is required ; this depends microphone used. or slow it down, he should take into con- recorder should contain switching fa- upon the particular sideration that this attempt is likely to cilities to vary the record equalization Information on the necessary input im- He may improve speed accu- with speed. Some machines, however, pedance should he obtained from the backfire. the input racy, but at the same time he may cause employ the same record equalization at microphone manufacturer. If is less, an increase in wow and flutter, which are both speeds. The result is that frequency impedance of one's tape recorder generally more deleterious to satisfac- response-in terms of smoothness as the necessary modification should be tory musical reproduction than are well as range -is not as good at either made by a service technician. (usually moderate speed errors. The user's best speed as it might be, because compromise A high -quality tape recorder and recourse is to take a seriously inaccurate equalization is used; or else the result is the semi-professional professional input for a low - machine back to the point of purchase. that, if good frequency response is main- ones) will provide an tained at 7.5 ips, then response is con- impedance microphone, which permits a recorder Equalization siderably short of as good as it might long run of cable to the tape he at 3.75 ips because the other speed has without loss of high frequencies and equalization (Fig. 7), or a NARTB been favored. which is less sensitive to hum pickup close approximation thereto, is consid- than the high impedance type. for tape ered virtually standard today Inputs recorders operating at 7.5 ips. Accord- Outputs ingly, the tape recorder should provide Tape recorders customarily have two Although a tape machine may contain NARTB playback equalization within ' nputs. One is for high -level sources, its own power amplifier and speaker, it 2 db at 7.5 ips. Otherwise, when play- such as the signal from a tape output still provide an output jack for ing commercial recorded tapes, fre- jack of a control amplifier, or the signal should quency response may depart signifi- Inasmuch as most cantly from flat. VOLTAGE SPEAKER IN machines that depart from the NARTB AND TAPE MACHINE playback characteristic provide inade- POWER response AMPLIFIER quate bass boost, the resultant PLAYBAC K when playing a recorded tape will be a HEAD These machines some- M1111140. OUTPUT JACK FOR thin bass sound. EXTERNAL SPEAKER times apply considerable treble boost in none is called for by playback, whereas Connection to internal speaker is broken when /' NARTB (except to compensate for head phone plug from external speaker is inserted deficiencies), so that shrillness is intro- speaker duced when playing a recorded tape. ig. 11. Means for automatically disconnecting a tape machine's internal With respect to the 3.75 -ips speed, the when an external speaker is plugged in. equalization question is not settled at the present writing. For a time, equalization such as in Fig. 8 was employed. Re- RECORD AMPLIFIER cently, however, there has been a trend RECORD employing NARTB equalization INPUT RECORD HEAD toward HEAD 7.5 0--- AMPLIFICATION -+ EQUALIZATION -- (Fig. 7) for 3.75 ips as well as for - DRIVER ips. and 15 MONITOR OUTPUT JACK Assuming that NARTB playback (FOR EARPHONES, METER equalization is employed at both 7.5 ips OOSCILLOSCOPE, ETC.) and 3.75 ips, nevertheless, different re- with a monitor output jack. cord equalization will he required at Fig. 12. Tape machine AUDIO AUGUST, 1959 38 You should know there is something better... New HI- Fl STEREO

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AUDIO AUGUST, 1959 39 lower or other low- impedance circuit (such as a plate follower) in the output stage. IN OUT O O- Fig. 13. Most fre- - -TAPE MACHINE quently used Input Sensitivity TAPE OUTPUT JACK method of feeding When recording from a source other signals from a o' than a microphone -FM tuner, AM POWER high fidelity sys- TUNER CONTROL TV sound, phono pickup -most AMPLIFIER AMPLIFIER tem to a tope ma- tuner, chine. audiofans will obtain the signal from a PHONO control amplifier, as illustrated in Fig. SPEAKER 13, rather than by feeding the source directly into the tape recorder, as shown in Fig. 14 (where the source is a tuner). In a number of control amplifiers, the N OUT the r o o incoming signal is routed directly to a tape Fig. 14. Seldom - tape output jack (for feeding TAPE MACHINE used method of recorder), without amplification or at- feeding a signal tenuation of the signal, as illustrated in from a high -fidel- Fig. 15. Since high -level sources gen- TUNER CONTROL POWER I i ity system to a AMPLIFIER AMPLIFIER erally produce at least 0.5 volts on tape machine. I PHONO peaks, it would appear that a tape re- SPEAKER corder sensitivity-input signal required TV Tuner cable temporarily disconnected from control to drive the machine to full permissible amplifier to feed tuner signal to the Igoe recorder. recording level -of 0.5 volts is sufficient it is feeding an external audio system. Pref- cording directly from a tuner or phono- for high -level signals. However, erably, for minimum distortion, the sig- graph, one can at least check the quality advisable to allow for two contingencies: source that nal should he taken from a point prior of the incoming signal. Or one could at- (1) the occasional high -level the de- to the power amplifier of the machine. In tach an oscilloscope or meter (high im- produces less than 0.5 volts; (2) normal record- some units, however, there is an output pedance, to avoid loading effects) to sirability of going above jack designated for feeding either an evaluate the nature of the signal with ing level, as for example on speech, external speaker or an external ampli- respect to amplitude, transients, fre- where distortion is less apparent than -level in- fier; in th }s:ease the signal is taken after quency response, and so on. on music. Accordingly, the high the internfipower amplifier. The better To permit a long cable rum from the put sensitivity of a tape recorder should situation is where there are two output tape machine to the following equipment be about 0.1 to 0.2 volts. illus- jacks, one for feeding an external am- without high -frequency loss, a low out- In some control amplifiers, as plifier and the other for feeding an ex- put impedance is desirable. It is for this trated in Fig. 16, the incoming signal level -set ternal speaker, as illustrated in Fig. 10. reason that the output jack in some ma- first goes through an input To obtain as flat response as possible, chines is connected after rather than control. Then it goes through a stage of output it is ordinarily desirable that the signal before the power amplifier stage (we are gain before reaching the tape may be restored at the output jack be taken from a point speaking, of course, of those units hav- jack, at which point it level. How- prior to the machine's tone controls, if ing their own power amplifier and to approximately its original such any. In some machines, however, the tone speaker). A preferable course is for the ever, there is no assurance that controls are employed as part of the machine to incorporate a cathode fol- (Continued on page 95) equalization circuit, and in this case one would want the playback signal after TAPE OUTPUT JACK TUNER O (FOR FEEDING SIGNALS the tone controls. At the same time, it is TO A TAPE RECORDER) necessary to ascertain the position of TVO 0 1 FOLLOWING STAGES OF these controls that achieves flat response. TAPEO THE CONTROL AMPLIFIER If the tape machine contains its own AUX O power amplifier and speaker, means MAGNETIC _ SIGNAL SOURCE should be provided for cutting off the in- PHONO SELECTOR SWITCH ternal speaker wheíu the signal is fed INPUT PREAMP to an external sound system. In some JACKS cases this is done automatically when a plug is inserted into the output jack, as Fig. 15. Method employed in some control amplifiers for feeding incoming signals shown in Fig. 11. directly to a tape recorder. Some tape recorders contain a monitor jack, so that when recording one can INPUT LEVEL SETS listen to the incoming signal with ear- JACKS TAPE AMPLIFICATION -0 OUTPUT phones, as shown in Fig. 12. While this STAGE JACK gives some evidence that the recording O signal is getting through, it is not posi- ---FOLLOWING STAGES OF tive signal is being satis- proof that the THE CONTROL AMPLIFIER factorily recorded. Such proof is ob- SELECTOR tained only by using a machine with SWITCH LEVEL SET separate record and playback heads, PREAMP which permits the signal being recorded to be played back immediately and signals checked. However, a monitoring jack Fig. 16. Method employed in some control amplifiers for feeding incoming does have worthy uses. Thus if one is re- to a tape recorder. AUGUST, 1959 40 AUDIO ouk ntuSiC S (l IitP,VtitOhLi ! IF ITS WORTH LISTENING TO THE FIRST TIME... IF YOU'D LIKE TO HEAR IT AGAIN... RECORD IT!

Viking equipment offers unmatched quality in the stereo recording of AM FM and FM Multiplex programs and in the duplicating of stereo discs. Once recorded, your tapes can be played as often as you wish without deterioration. Your investment in Viking tape recording equipment can be your most economical source of Hi -Fi reproduction. You can expect performance in accordance with the following spec- ifications: Frequency response 30 to 14,000 cycles, 2 db. Signal to noise

ratio 50 db minimum. Flutter and wow .2 %. Total harmonic and inter - modulation distortion less than 2 %. Most important, compare performance. Ask your high fidelity dis- tributor for a demonstration of Viking recording quality.

Viking's Customer Service Department provides a free planning service - to help you with integration 11111b.. of tape equip- : ment with your music system.

OF MINNEAPOLIS, INC.

9600 Aldrich Avenue South, Minneapolis 20, Mir. n.

AUDIO AUGUST, 1959 41 Variable Electronic Crossover and Biamplifier

GEORGE C. KANE'

The author describes a combined variable electronic crossover and a biamplifier that has a mid high- frequency power output of 20 watts and a low- frequency power output of 50 watts.

4NY AuncoPANS who build their properly designed and constructed it wife-she didn't want a chassis (elec- M own hi -fi equipment, and some can produce hum and noise. There are tronic crossover) to remain on top of who purchase kit -type compo- other pro's and con's that will not be a choice piece of furniture (no space in nents, soon realize that the cabinet space taken up here. the cabinet), nor did she approve of an allotted to the system becomes too small. There are two general types of elec- amplifier (additional amplifier for The author's system went through the tronic crossover units. One has a fixed treble) on the floor behind a chair. usual series of speaker additions and as- crossover frequency, the other type con- Since the original space for the ampli- sociated L -C crossover networks. The tains a method of varying the crossover fier could not be enlarged, consolidation frequency of crossover could not be frequency. To the author, the type of components was necessary if the elec- varied so there was always a question as having a variable crossover seemed most tronic crossover was to be retained. After to whether the speaker performance desirable. The first model constructed many hours at a drawing board and could be improved with a change in contained a switch that was used to trying different arrangements of parts crossover frequency. change capacitor values in the variable on various shapes of chassis, the com- Recently, a new component -a Varia- portion of a low -pass and a high -pass bined electronic crossover and biampli- ble Electronic Crossover- appeared on filter, resistor values remaining fixed. fier shown in Fig. 1 was constructed. the market. The electronic crossover An old amplifier was brought out of re- The complete schematic is shown in seemed to have some desirable features tirement and the system placed in op- Fig. 2. and some not so desirable. The good fea- eration. The speakers seemed to take on tures are that it contains a method of a new brillance not heard before. Re- Electronic Crossover changing the crossover frequency, re- sults were excellent until the crossover Section duces intermodulation distortion, ab- frequency switch was changed to another A block diagram of the variable elec- sorbs no audio power, and does not crossover frequency -the thud that came tronic crossover portion of the biampli- affect speaker damping. Undesirable fea- from the speakers was powerful enough fier is shown in Fig. 3. The output of a tures are that it requires another ampli- to toss the speaker cones into the middle preamplifier feeds two level controls, fier (one for each channel), and if not of the living room! Another undesirable one for the high -frequency channel (for the purpose of this article, high -fre- ".50 Queens Drive, Little Silver, N. J. feature was pointed out by the little the quency channel is called the treble chan- nel although it may contain frequencies TI Va p1 V9 C33 below several hundred cps), and one for the low- frequency, or bass, channel. Each channel is then coupled to a voltage am- plifier where the program material is amplified and passed on to a cathode follower. So far, both channels are the same with the exception of the coupling capacitors (C,, C2, C,,, and C15i in Fig. 2), but here the similarity ends. Nega- tive feedback is provided through re- T3 sistors R5 and R55 to improve frequency response and to reduce stage gain to about four. Cathode follower Vi,, feeds a high pass filter, (B) in Fig. 4, consisting of two R -C sections. The impedance ratio of the first section to the second section is 1 to 4. Therefore the slope of the curve FI is approximately 8 db per octave. Cath- ode follower V,g feeds a low pass filter, (A) in Fig. 4, which attenuates high frequencies at the same 8 -db- per -octave rate. The filters present curves that are R32 C22,C28,R1I,R13 VI \. V2 C7,Cl2, 3 (4 cd; ow C zCie inversely symmetrical, (C) in Fig. 4. Fig. 1. The author's biamplifier, showing placement of major parts. When gain controls R, and RJ, are ad-

42 AUDIO AUGUST, 1959 a new tweeter that solves at least three of your speaker problems!

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..°¡.°:in.::i.+¡:¡'.'¡i: yy...... :a..;¡:..: >r , .. ,Y....!.. . . . ° J JM..,...... T1 ...... ,!V..^

SOUTH AMERICAN TROUPIAL BIRD PHOTOGRAPHED AT TREFFLH:H'S, NEW YORK the ah!* electrostatic transducer 153/47r ---4 A Combination Mid -Range and Super Tweeter The 'ah!', because of its revolutionary Oparent new construction gives clear, trans- response on all frequencies from 600 cps to beyond the limit of audibility and has none of the limitations of tonal coloration and exaggerated peaks in cone or piston type tweeters! found © The 'ah!', because of its omni -directional characteristics, offers tremendous elfT~ advantages in your stereo system. The 'ah!' enables you to space out speakers Mates easily and quickly to any speaker made. to achieve the Frequency dramatic effects associated with wide separation without the Response: Full flat, lifelike midrange disturbing "hole-in- the -middle" plus UHF coverage -600 cps to past the limit of caused by the directional characteristics of audibility. conventional speakers by Roll off 6 db /octave of speaker and ... or single-ended, high distortion, limited range crossover network below 900 cps. Backwave electrostatic speakers. completely undamped. Impedance: Designed to match 8 or 16 ohms The output 15 © 'ah!' electrostatic transducer is superior in quality and performance to of to 50 watt amplifier. speakers selling Crossover: Self- contained R/C crossover net. for almost twice as much, but, because of expert work; recommended facilities and newly developed research crossover point between materials it is offered at an unprecedented low 650 to 850 cps. May be connected in parallel price ... only $49.95. directly across any low frequency woofer with. out additional network. Nothing else to buy R/C crossover Sound Dispersion: Full 180° coverage (front and - network and backwave) when speaker is mounted at least AC power supply are built in. 8 or 16 ohm L pad 6" from back wall. may be added to attenuate tweeter, if desired. Distortion: Practically unmeasurable. Radiation area is 62 sq. inches. Polarizing Voltage: Fused currentless 1000 volt An American -made speaker patent DC power - GUARANTEED FOR FIVE FULL YEARS, supply. 110 volt AC power line. applied for by COSMOS INDUSTRIES. elements Hand rubbed genuine walnut cabinet, other fin. / are practically indestructible. ishes available on special order.

EAST COAST the 'ah!' electrostatic transducer can now be seen at WEST COAST For complete information and HUDSON RADIO specifications IFONARD RADIO AT THISE AMER NIOM FIOFtITY STORES See write to: 48 West 48th Street IN THE your local New York City 69 Cortlandt Street MIDWEST Voice & Vision Inc. Volte & Vision Inc. high -fidelity new York City 921 N. Rush Street 7055 W. North Avenue dealer. 212 Fulton Street ChiGao 11, Illinois Oak Park, Illinois COSMOS INDUSTRIES, INC. New York City NAM FT RADIO Allied Radi. Corp. (lied 35 William Street 103 West 43rd Nigh Fidelity Inc. Allie High Fidelity Stores 11 ee s Sotdevar Street 100 N. Western Avenue 2025 W. 95th Newark, New Jersey New York Street 602 avis Street \ City Chicago. Illinois Chicago, und Illinois Isl-28 (von ton, Illinois \ -Long anQd City 1, New York

AUDIO AUGUST, 1959 43 of the control adjusts so that the flat portions of the The crossover frequency is changed clockwise position ;lusted of curves are at the same level, the point by varying the crossover control which the filters to about 1200 cps. Types required for the crossover where each curve is down 3 db (half - has four variable resistances (R,,. R,, , resistances control are given under "con- power point) is the crossover frequency. R;7, : d R,o) combined into one eon - frequency At the 3 -db point, each filter is de- trol. When the control is in the counter- struction details." half power and the two filters clockwise position (resistances at maxi- livering Treble Amplifier together deliver full power resulting in mum) the filters are adjusted to a of high -pass filter net- an overall curve that is fiat. crossover frequency of 100 cps. The full The output the

R34 R31

C4 + 22K 2W R20 47 K C12 5600 2W KT66 201450 V

CIO TI 0.1 0o Q TAW OUTPJT o 8

0.1

C11

0.1 4 RI8 1200 KT66

° C8 `680

I CROSSOVER 1_ _ _j

I FREQUENCY

R44 R63

47 K 20 22 K 2 R 56 5600 2 C22 C28 1475 EL34 20 Y V7 4 BASS I 475 V O OUTPUT r , C26 .25 R61 16

20 I V5B V6A V6B C17=450V L 12 C19 R46 R47 25 K R48 R50 ñ 2200 8200 R49 10 K 100 K R39 COM R62 1000 2 Mee A C20 .043 C21 .01 V8 C25 EL34 R53 390 C29

1000 + 50 C24 680 oe

73 5V ^^LItlyfl9

l4 Hy. 200mo

VI V? V3 V4 V5 V6 V7 V8

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R66 300 R67 110V 60

20 W 18 K C30 + C32 + C31 + C35 C36 40 500 V 40500 V 3DT475 V 0.1 0.1 PREAMP

30

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1C34 o .25 T4

o 110V CRI 35 ma R68 R69 R70 °MATCHED PAIRS SHOWN 1 OTHERWISE IOK 5000 6800 ALL RESISTORS WATT UNLESS 65 mo

Fig. 2. Over -all schematic of the electronic- crossover amplifier. AUDIO AUGUST, 1959 44 PROBLEM SOLVED BY PILOT: Develop a fine "bookshelf" speaker system that gives equal performance in vertical or horizontal positions.

It was almost easy once Pilot engineers started to work on it. As they saw it, the system should have five speakers (you'd be surprised at how few others do), a 12" woofer plus two mid -range and two treble speakers angled for optimum dispersion. But then, if you mount- ed the enclosure in other than its prescribed position, the tweeters and mid- ranges would be dispersing, yes, but into the ceiling and floor! Pilot's answer: the exclusive Acoustimatic Turret -with four speakers two angle -mounted 6" mid -range and two angle -mounted- 3" treble speakers. With a simple control at the rear of the enclosure it takes only a few seconds to rotate the turret so that these four speakers disperse the sound horizontally, regardless of the position of the enclosure. (Even the Pilot nameplate rotates so that it looks at you right side up !) The four speakers in the Pilot Acoustimatic Turret, plus the big 12" heavy -duty woofer with 1" cone excursion give you clean, solid, well- defined bass, smooth response, and overall per- formance never before achieved ina "bookshelf" speaker.

MOUNTS THREE WAYS

:1 - 447' ._.= : " -- r , , _ r , , I -'` -- 1; -!

PILOT PROUDLY PRESENTS THE PSV -1 SPEAKER SYSTEM 12 -inch Air -Flex heavy duty woofer, front mounted to seal the opening of an air -tight, Orlon fiber filled enclosure. Tweeters and mid -range units mounted to eliminate the intervening ducts of conventional thick baffle boards, and remove all possibility of distortion and tone coloration from such ducts. Separate Presence and Brilliance controls sup- plied to match the PSV -1 to individual acoustical require- ments. SPECIFICATIONS: Woofer -Pilot Model 53 Air -Flex 12 -inch low frequency driver. Frequency range 40 to 800 cycles. Free air resonance: 22 cycles. Mid -range -two Pilot Model 40 6 -inch mid -frequency cone -type direct radiator loudspeakers. Frequency range 800 to 8,003 cycles. Tweeters -two Pilot Model 44 3 -inch cone -type direct radiator loud- speakers. Frequency range 8,000 to over 16,000 cycles. Crossover network -6 db /octave, air -core inductance capaci- tance. Crossover frequencies: 800 cps and 8,000 cps. Imped- ance: 16 -ohms. Overall frequency response: 40 to 16,000 cycles. 45 pounds. Size 253/4" x 141/4" X 12" deep. Fully finished on all four sides in a choice of hand- rubbed mahog- any or walnut, as well as oiled walnut. $139.50. PILOT PIL RADIO CORP., 37 -0, 36th Street, Long Island City 1, N. Y. Founded in 1919

AUDIO AUGUST, 1959 45 The circuit of the bass amplifier is TREBLE similar to that of the treble amplifier. GAIN VIA V1B VARIABLE TO Tube V, is used as a voltage amplifier VOLTAGE CATHODE HIGH PASS TREBLE AMPLIFIER FOLLOWER FILTER AMP. and phase inverted which drives two C EL -34 tubes also in push pull Ultra - Linear operation. Fixed bias is obtained INPUT from a rectifier in the power supply. FROM PRE AMP The bass amplifier develops 50 watts at BASS 0.76 per cent intermodulation. Resistor GAIN : provides a V5A V5B VARIABLE TO RG2 serves two purposes It VOLTAGE CATHODE HIGH PASS BASS test point for proper plate current (1.56 AMP. AMPLIFIER FOLLOWER FILTER volts) which in effect is added to the fixed bias, and since R6, is unbypassed it produces a small ampunt of current Fig. 3. Block diagram of variable electronic crossover. feedback. Any unbalance in grid signal or a.c. plate current causes a negative to the input 20 -watt amplifier seemed to be a good work is connected directly voltage across the resistor. The feedback Fig. 2. This par- companion to back up the bass ampli- of the treble amplifier, voltage reduces distortion that may be ticular amplifier circuit, which is es- fier which is rated at 50 watts. caused by the unbalance. Resistor R,,, of Dynakits was used Tube V2 is a pentode- triode. The pent- sentially that the provides the necessary feedback. because of its simplicity and excellent ode (section A) is used as a high -gain performance. The treble amplifier con- voltage amplifier. It is directly con- Power Supply tains only three tubes and a relatively nected to the triode (section B) which The power supply furnishes 130 ma small number of parts. Power output is is used as a cathodyne or split -load at 420 volts for the treble amplifier, 20 watts with slightly less than 1 per phase splitter. Grid return for V.4 is 140 ma at 450 volts for the bass ampli- cent total harmonic distortion. Inter - through part of the high -pass filter, R,r fier, 20 ma at 300 volts for a preampli- modulation distortion is 1.3 per cent at and R,3. The output of the phase split - fier, and 30 to 50 volts bias for the 20 watts output and is under 0.5 per ter is connected to V, and V4 (KT -66's) EL -34's. Linear cent at 10 watts. which are operated in Ultra- Full-wave rectification with two (Note: Since the photograph in Fig.1 push pull. Total plate current of 120 5V4GA tubes, each having its plates was taken, transformer T, has been milliamperes (60 ma per tube) is ob- connected in parallel, (the 10 -ohm re- the slider on re- changed from a Linear Standard LS -63 tained by adjusting sistors, R73 -R76 balance current through to to an Aerosound TO -300. Plate -to -plate sistor RS0. Resistor RP7 is used bal- the two halves) was used to obtain the is impedance of the LS -63 was found to ance plate currents. A balance 280 ma required by the amplifiers. A across re- be too high for the KT -66 type tubes obtained when the voltage separate 1 -to -1 transformer, T4 and a when operated in the Ultra -Linear con- sistors R,, and R is zero. Plate current half -wave rectifier CR, furnishes the the voltage nection.) is the correct value when 30-to -50 volt negative bias. Capacitor A few eyebrows may be raised when across each of these resistors is 1.5 volts. Cr, filters the bias supply. The two db of seeing a 20 -watt amplifier being used Resistor R,, provides about 18 B -plus voltages are filtered through for the "Treble" range. However, when negative feedback. Taps on the primary separate circuits. The filament circuit is using a crossover frequency of 200 -300 winding of transformer T, provide the positively biased to about 40 volts by a cps, some rather low frequencies must necessary screen feedback for Ultra - voltage divider of resistors R7, and R72. be amplified by the treble channel. A Linear operation of the output tubes. Construction Details The amplifier is constructed on a heavy -gauge steel chassis base 3 in. high C5 C6 deep and has a R46 R47 R48 R49 by 14 in. wide by 10 in. grille type metal cover. The chassis must be made of heavy steel because two of the transformers each weigh about 14 IN C20 C21 OUT pounds. The completed amplifier weighs OUT IN \ 48 pounds. Location of parts (Figs. 1 and 5) is very important. The power -supply com- T T ponents are mounted at one end of the (A) LOW PASS (B) HIGH PASS chassis, the treble amplifier in the middle +s amplifier at the II section, and the bass other end as far away from transformer T3 as possible. A steel shield is mounted Z s ,r I on the underside of the chassis to isolate 5 4.P;1. d4Y, CP ' `15^' `.a` the external fields of transformer T4 -10 TC Q filter choke L,. The shield also pro- O t .( ? t z and 5 15 vides valuable space for mounting parts Tube shields are / e of the power supply. 20 the 6AN8's to ee `` used on the 12AU7's and 25 prevent hum pickup from the partially

20 shielded power transformer. .RI IOW two sep- FREQUENCY IN CYCLES PER SECOND Filaments were wired by arate pairs of twisted wires from the supply section, one pair supply- the biamplifier: (A), the low -pass power Fig. 4. Configuration of RC filter networks used in tubes, and the response curves of the two sections at ing the power output section, and (B), the high -pass section. (C), small tubes. The maximum and minimum crossover frequencies. other supplying the AUGUST, 1959 46 AUDIO . _ ':: a..

Win your next Rolls-Royce...

The superb $13,995.00 automobile illustrated will be awarded to the reader of this message who listens to a Shure high fidelity Stereo Dynetic phonograph cartridge demonstration and best describes its singular sound re- creation qualities (in 25 words or less). No purchase is required. If, however, you are the winner and have purchased a Shure cartridge (our thinly disguised motive for sponsoring this competition) you may accept your automobile at the Rolls -Royce factory. Travelling expenses for yourself and a friend to the British Isles and return will be defrayed by Shure Brothers, Inc., 222 Hartrey Avenue. Evanston. Ill. Should you win (we don't expect an overabundance of entries, so your chances are rather good) you'll probably never have to buy another automobile as long as you live.

Details and contest blanks available only at high fidelity dealers' show rooms and salons. Contest ends August 31st, 1959.

SHURE

high {fidelity Stereo Dynetic phonograph cartridges , . . Unanimous choice of the critics. Model M3D, $45.00 net; Model M7D, $24.00 net. L

AUDIO AUGUST, 1959 47 -4u rvv carries power to the preamplifier. These because rrrym - ? ? ñ leads were run separately the rrc>ñáu u. uu u primary' current of transformer T3 is about 2 amperes. Ground throughout the amplifier is a #14 tinned bus wire 5K which is connected to the chassis near 539 the input jack. All electrolytic capacitors V3 R3' are mounted on insulating wafers and vs w the shell connected to the ground bus cIF wire. Speaker connections, bias control 538 Rfei and preamplifier power socket are C28 mounted on the rear apron of the chassis. R61 C25 u An unusual feature of this amplifier is

ve 530 that it does not contain a single half - va watt resistor! It is true that the current V9 584 in some circuits warrant the use of a VIO T6A half-watt, or even a quarter -watt, re- R66

568 sistor but this audiofan has encountered C79 several sad experiences with them.'

R67 c30 Adjustments C3I C12 The only adjustments required are C33 bias for the EL.34's and balancing the KT -66's. Proper bias (and correct plate current) for the EL -34's is obtained by R69 R31 CRI R71 adjusting R69 until a voltage of 1.56 volts is measured across R64. The cor- Fig. 5. Underside of amplifier chassis showing parts placement. rect balance and plate current for the KT -66's is obtained as follows: Connect filaments were wired first, keeping the filter and capacitors Ct6 and C2, in the a low -range voltmeter across resistors close low -pass filter are selected values that leads to the chassis. R69 and Rss (pins 8 of Va and V4) and Because of the large number of parts are within 1 per cent of desired value. adjust resistor R27 for zero voltage. The .02 in the amplifier, terminal board con- C6 was made up by paralleling -µf voltmeter is now connected across Rae struction was used where possible. Two and .004 -sf units then measuring the (or R33) and the slider of resistor Rso terminal boards are mounted along the combination on a capacity bridge. Cro adjusted until an indication of 1.5 volts front apron of the chassis. These boards is an .0470 unit that actually measured is obtained on the meter. The balance mount most of the parts required in the the desired value of .043µf. Resistors adjustment should be checked by re- input circuits and the electronic cross- R,o, R12i R46, and R48, although stand- peating the zero -voltage measurement over networks. Parts associated with the ard values, were measured and selected previously described. crossover frequency control are mounted to be within 1 per cent of the desired Several "tests" were made on the over- on the boards as close to the control as value. (The author's parts dealer loaned all amplifier such as power output and possible. This allows short leads to the a handful of capacitors and resistors so frequency runs at different crossover cathode followers and to the grid of the correct values could he selected, al- frequencies. Figure 6 shows the results the 6AN8's where hunt is likely to be lowing return of the parts that could of one "run" and indicates the over -all picked up. Two other terminal hoards not be used, my thanks to him.) Resistor response at an output of 10 watts. Cali- moult parts associated with the bass pairs such as R., and X22, Rt7 and R68, bration figures on the frequency control and treble amplifiers. Coupling capaci- R69 and RG0i and It, ?2 and Ras were (Fig. 1) are approximate only, since tors were put in last. Terminal board matched to within 1 per cent. Such exact- in operation the exact value does not construction makes removal of parts ness may not be necessary but on an mean much. easy, does not clutter the socket pins, overload test, it's nice to see clipping at (Continued on page 83) and if properly assembled actually re- both grids of each power amplifier take One experience similar to that ex- duces capacitance between parts and place at exactly the sanie level. plained by Walter Richer, in "The sad tale chassis. The hoards were assembled on Some preamplifiers have the 117 -volt of a half -watt resistor," Avaao, December, the bench, then mounted on the chassis power switch leads within the cable that 1957. and wiring completed. The crossover frequency control is as- sembled by using one IRC "PQ" control and three "M" sections all having a linear taper. The control consists of one 25 -k "M" section IRC (M11 -120), two Fig. 6. Response of the two sec- 100 -k "M" sections (M11-128) and a ° 5 Ó tions of the biam- 3 g 2 lo 25K "PQ" standard control (PQ11- plifier with the 120). (standard control) is the basic Q R crossover control S ó control and is next to the front apron. cps. set for 350 ? -20 Instructions for adding the "M" sec- Z tions to the "PQ" control are packed O -a5 O with the control. Particular attention á -30 Z LI must be given to wiring this control since with clockwise rotation of the O s -10 WATTS IN 16 OHMS CROSSOVER FREQUENCY= 350 CPS shaft, resistance must decrease thereby to increasing the crossover frequency. KO laW FREQUENCY IN CYCLES PER SECOND Capacitor Cs and C6 in the high -pass AUGUST, 1959 48 AUDIO Years Ahead New Bogen stereo receiver is years ahead in price and in performance

NO ONE BUT BOGEN, builder of over one million high- fidelity and sound - distribution components, could have engineered this new high -fidelity stereo receiver, the SRB 20. A superb all -in -one stereo instrument, it's a highly sensitive FM -AM stereo tuner,

- it's a versatile stereo audio control center, it's a magnificent 20 watt (10 per channel) stereo amplifier, and it's yours for only $199.50 -a price you'd expect to pay for a comparable tuner alone!

BOGEN'S ENGINEERING STAFF, largest of any sound -equipment maker, de- signed each circuit stage of the SRB 20 as an individual unit. By concen- trating on each stage separately, they can pack more value, more clean fir( performance in less space than is ihdirffir otherwise possible. The separate stages are then carefully, logically arranged in an overall circuit of proven superiority. This new Bogen concept eliminates wiring clutter, prevents hum and distortion, provides savings which are passed on to you. Bogen's engineering excellence, crystallized during 25 years of building specialized sound systems for schools, theatres, industrial plants and offices, is yours to enjoy in the new SRB 20. Put it in a cabinet or on your bookshelf (it fits easily). Ask your Bogen dealer to show it to you today.

BOGEN CONTROLS: Selector, FM Tuning. AM Tuning. Separate Bass -Grue, 4,o4uutcC, -t,o_akj.. and Treble for each channel (lock for simultaneous control of both). Volume for each channel (correct imbalance, then to wuteyC, btoz.eo lock for simultaneous control). Separate On -Off Power. FM On -Off and AFC. AM On -Off. Multiplex. Send for illustrated booklet, "Understanding High Fidelity." 64 -page explanation of hi -fi and stereo. Enclose 25c please. HIGH FlDEIJrY

nocENmtEsro co., Dept. A89, P. 0. Box 500, Paramus, N. J. A division of the Siegler Corporation

AUDIO AUGUST, 1959 49 Hi -Fi for Lo -Do

S. G. LUCAS*

While most of us would prefer a factory -built cabinet, the lack of "dough" may make it necessary that we "do" it ourselves. And if you don't have a power saw, it seems likely that there is a lot of the "do" required to turn out this professional -type speaker enclosure.

RE YOU WILLING to gamble less than TABLE I $25 and about 10 to 12 hours 3/4 -inch plywood the actual living presence work for piece 22'/2 x31 Bottom of Bach, Beethoven, Brubeck, or Good- 24 x 32'h Top man via this back -loading folded horn 32'/z x 41'/4 Front for your listening pleasure? 17'/2 x 49'/4 Back This horn is designed for use with 4 3/e x 31 Part A 23'/e x31 Part B woofers having resonances of about 55 15'/z x 31 Part C cps but will work very satisfactorily 4 x 12'/4 Part D with much lower resonances and slightly 11 3/4 x 31 Center Shelf higher resonances. The theoretical cutoff 125/16x 31 Lower Shelf pieces l0 5/s x 49'/4 Part E frequency is 40 cps but good perform- 163/4 x 41'/4 Sides ance will prevail down to 30 cps. Lumber The cabinet is basically the Jensen piece 1'/z x2'/ x 29 Top Stiffener Imperial reproducer -a hyperbolic -ex- 1 1/2 x 2'/z x 40 Back Stiffener ponential design (covered by U.S. Pat. 1% x 3% x 64'/2 Base 1 x 1 x 761/2 2,338,262) be used as a free- stand- Cleats -to pieces 3/4 x 25/a x 481/2 Cleats type for corner or sidewall place- ing 1 '/2 X 1 1/2 X 48'/2 Posts ment. I plan on installing the Jensen All dimensions in inches KT -31 speaker kit, but any combination employing a 15 -in. woofer or a 2 -/or a- tain the best results. Except for such in. smaller all around than the top -so way as the Electro- assembly -such parts as the base, posts, cleats, and be sure you pick the correct one to Voice Model 15 TRX; the University stiffening members, 3/4 -inch plywood is start your construction. Next, take the Model 315 -C; the James B. Lansing used throughout. All joints should be corner posts and cut two sides of each Model D130, etc. be mounted into -can adequately glued and screwed to main- with a notch 1/4 in. deep and % in. this folded horn. tain rigidity. wide, with the upper edge of the notch In Figs. 1 and two 4 ft. x 8 ft. 2-on The following construction procedure 8 in. down from the top of the post. plywood sheets shown the lay-outs -are is suggested: Begin by cutting out the Glue and screw these corner posts to of the various panels that are needed bottom and the front panel and he sure the front panel -but be sure and mount to construct this speaker cabinet. Be- that these first cuts are square to insure them in. in from the side edge and low are listed the measurements of these 3/4 a tight fit. The centerline of the speaker 3/4 in. up from the bottom of the front panels, plus the necessary lumber needed opening is 113% in. from the bottom panel in order to leave room for later for the bracing and the base. edge and located on the vertical axis. fastening the bottom and side panels. An important point to remember in This opening may be cut to accom- Figure 3 shows how Part A-4% x 31 building your cabinet is that all joints modate either a 12 or 15 in. woofer or -is attached to the notched corner posts must be accurately fitted and that it your present tri- or co -axial speaker. and the front panel. I glued and screwed must be made as rigid as possible to ob- Upon checking the list of materials, you these panels together and with the use " 322 Park Avenue, New Castle, Pa. will note that the bottom panel is 3% of clamps to hold them firm, then let

Fig. 1 (left). Layout of one of the plywood sheets is the initial step in the actual construction. Fig. 2 (below). Lay- out of the second sheet to make sure you get all the parts out of the two pieces of plywood.

E SIDE

SIDE

CENTER LOWER C SHELF SHELF BACK

4 x 8 fr. PLYWOOD

50 AUDIO AUGUST, 1959 PRESENTING THE JBL RANGER -MINIGON

The new 1BL Linear'Efficiency Speaker, with its small enclosed-airvolume require ments, permits the use of radial refraction in an acoustical enclosure measuring just

32" wide, 15'A" deep, 12 %" high. The same method of projecting a broad stereo field that originated with the fabulous JBL Paragon and was popularized with the JBL Metregon is used in the Minigon. One Minigon gives you the highest fidelity monaural reproduction ever provided by a minimum size enclosure. Two will give you enviable stereo, integrated by the curved refracting panels. Usually placed end to end, Minigons may be separated a reasonable distance without disturbing the stereo field. Your choice of louvered wood or fabric grilles. Hangers for wall mounting are built in.

New JBL Dale Enclosure, Model C49. for JBL Linear. Efficiency drivers measures

23,4" a 11% " a 12" high, is delightful in its simplicity. refreshing in its restrained use of interest-arousing design details.

New JBL Madison Enclosure. Model C48, 23% "x 13i / "x IIr /" high. reflects the influence of Danish design. Finished on four sides and front, the Madison may be used in either vertical or horizontal position.

®LSV`i,f1NS NEWEW

Il Y Ul.à Vrri'SD®11 V

I¡¡jjI r/1 k® Wtr .J Oy J E A Il N LL Il U S FOR S.VLALL PRESENTING THE ENCLOSURES JBL LINEAR -EFFICIENCY SPEAKER You see an all new precision transducer that could only be a product of James B Lansing Sound, Inc. The company which brings you the best speakers for horn enclo- sures and the best units for reflex enclosures now offers the finest infinite baffle type transduces. Under intensive development for a year and a half, design judgment and engineerirg decisions were recurrently confirmed by analog computer. You will hear big, deep, accurate bass from these instruments. Application of new principles of cone suspension permits unusually long linear excursion. Relatively high efficiency with its attendant precision transient response, clean reproduction, least dynamic range is achieved by use of large voice coils, precisioninstrument tolerances, ad vanced magnetic circuitry -all typical of JBL transducers.

Illustrated above is the JBL Model LE10. the super 10" Linear Efficiency Low Frequency Driver. To the left are the new LX3 Dividing Network and the new JBL Model LE30 High Frequency Driver. To the ar left is the new LE8, the super 8" extended range LineaEfficiency Loudspeaker d which gives a flatness of response from 30 to 15.000 cycles that is without precedent in a unit of this size.

Write for a complete description of these new units and the name of the Authorized JBL Signature Audio Specialist in your community. JAMES B. LANSING SOUND, INC. / 3249 CASITAS AVENUE, LOS ANGELES 39 _ Fig. 3. The two notched corner posts are Fig. 4. Installing the center shelf. Note Fig. 5. Making ready for the installation Part B. the use of temporary attached to the front panel, and the base that two pieces of 1 x 1 have been at- of Note is attached next. Casein glue and plenty tached to the shelf before mounting on braces along the sides to keep the center of wood screws ensure a solid cabinet. the front panel. shelf in the correct position. them set over -night. porary braces to the ends of the center tween the lower shelf and the corner Figure 4 shows the installation of the shelf and the corner posts to position posts. Also shown is the speaker com- center shelf. First cut this panel - these pieces securely until ready for the partment panel, Part C -151/2 x 31- x 113/4 x 31-and two pieces of the 1 next step. with an access opening of 12 17 cut in in. x 1 in. lumber -one 31 ins. long and Cut Part B-231/8 x 31 -with a 12 in. the center. After this panel has been the other 28 ins. long. Glue and screw square opening cut in the center. Bevel glued and screwed to the center and be the 1 x 1 x 31 cleat to the rear, lower the top and bottom edges of this panel lower shelf, the other side can edge of the center shelf. Next, cut 11/2 to form a level plane with the upper mounted. in. notches in the forward edge of this surface of Part A and the lower sur- Figure 8 shows a rear view of the panel to fit around the corner posts. At face of the center shelf. Now lay the cabinet with Parts E mounted. Remem- this point, it is necessary to plane the cabinet assembly face down and glue ber to bevel the rear edges of Parts E rear edge of Part A and the rear edge and screw Part B into position. At this at 45 deg. At this point it is necessary of the center shelf approximately 20 point it is best to add a side panel to to cut two rabbets 1 x 3 x 481/2 beveled deg. to insure a tight fit of the network give additional support to the bottom. 45 deg. at one edge -these can be seen panel, which is fastened later. Mount If your speakers have any Tone or Bal- mounted at the rear of the inside of Part the center shelf 203/4 in. down from the ance Controls it is necessary to cut the E, so that the 45 -deg. bevel is such that upper surface of Part A. As can he needed holes in the side panel before it will form a 90 deg. corner in which seen in Fig. 5, I had nailed some tem- mounting. Also, don't forget to bevel the hack panel will fit. the rear edge of the sides at 45 degrees The progresses -part C, Fig. 6. Part B and one side installed; to make a smooth fit with Part E. Fig. 7. structure access lower shelf in place with small stiffening The above steps are shown in Fig. 6, with the large rectangular speaker- installed. Note space member between it and bottom panel. along with the lower shelf being added. opening, has been between lower shelf and corner posts. Also shown are 2 4 base members. Cut this panel -12 5/16 x 31-and slightly bevel the rear edge approxi- mately 6 deg. to insure a tight fit with Part C. Take Part D-4 x 121/4 -and bevel it so that it is 4 in. at one end and 23/4 in. high at the other end. Glue and screw Part D to the center of the lower shelf. Then mount this assembled lower shelf on to the bottom panel so that the front edge of this assembly is 23/4 in. away from the inner surface of the front panel and with the slant pointing down toward the front. Along at this time, you can cut two pieces of 2x4x163/4 and one piece 2 x 4 x 31 with the ends mitered, for use as a base. Mount these pieces to the bottom as shown in Fig. 6-the piece running across the back edge is just a temporary brace -which is removed later when the casters are added. Figure 7 shows how the various panels were glued previous to adding the re- maining side. Note the clearance he-

AUDIO AUGUST, 1959 52 NOW, FROM GENERAL ELECTRIC'S NEW 6L6-GC..

55 WATTS...with only 2% distortion without feedback*

Power for orchestral climaxes with full concert -hall brilliance ... yet mellow in tone, undistorted! You can build this high speaker power into your new equipment at a cost one-third less than the cost of other tubes with comparable performance! With 30 watts plate dissipation, 5 watts screen, General Electric's 6L6 -GC beam pentode can take peak power demands in stride. This is a new tube throughout, designed to handle easily the speaker requirements of the finest audio systems. Type 6L6 -GC has, among other features: Special 5 -layer bonded -metal plate, developed by General Elec- tric for improved heat conduction and radiation. New large heat radiator on control grid, to minimize grid emission. * Two 6L6 -GC tubes push -pull, Class Redesigned screen grid, for higher dissipation. AB1 service, with 450 v on the plate. New protective slots on micas, to reduce high -voltage inter- element leakage. New- design bulb, to radiate heat more efficiently. Key design -max ratings, per tube, of the new General Electric 6L6 -GC are: Top power output-low distortion -completely new design -economy! Four important advantages to you of General Electric's 6L6 -GC. Ask any Plate voltage 500 v G -E Receiving Tube Department office below for further information! Plate dissipation 30 w Screen voltage 450 v 200 Main Avenue, Clifton, New Jersey 3800 North Milwaukee Avenue 11840 West Olympic Boulevard (500 v with output transformer taps) (Clifton) GRegory 3 -6387 Chicago 41, Illinois Los Angeles 64, California Screen dissipation 5 w (N.Y.C.) Wisconsin 74065, 6, 7, 8 SPring 71600 GRanite9- 7765,BRadshaw2.8566 Cathode current 110 ma

Ft»gress Is Our Most Important Product GENERAL ELECTRIC 2.211.101 should be air -tight and that is why a liberal use of glue, wood screws and a caulking compound should be used. The best test for adequate rigidity is to thump the center of all panels with a clenched fist; a vibrating panel will quickly reveal its presence by the hollow, drummy sound indicating additional bracing is needed. Check Fig. 8-after installing your speaker to the opening, it is necessary to drill a small hole in the center shelf to pass the lead up to the network com- partment. Cut a panel -14 x 19 -as a cover to the opening of the lower com- partment and fasten with 11/2 -in. wood screws on approximately 6 in. centers. Next, cut a panel 14 in. square. Mount all your network units on this panel, drill a small hole in this panel as an opening for the leads, and then fasten securely to the 12 x 12 opening. Re- member that any small holes drilled for insertion of leads, should be made air- tight with the application of a plastic wood cement. If you have a midrange and /or super - use Fig. 8. The remaining side and parts E Fig. 9. In addition to the liberal of are now mounted in place, resulting in tweeters, they are to be mounted in the casein glue, as shown here, it is desirable this appearance. upper compartment on Part A and any to caulk all joints with a non -hardening controls can now be affixed. compound, such as linoleum cement. After all speakers, networks, and shows grill cloth secured The top of the cabinet can now be controls have been mounted, the back Figure 11 to the upper speaker compartment, and attached. Add a stiffening member- panel can be attached. To the vertical the excess grill cloth temporarily 11/2 x 21/2 x 29 across the middle of the center -line of the back, a stiffening mem- with same time, mounted on the front panel. Due to the under side of the top. At the ber -11/2 x 21/2 x 40- should be fastened. deg. size and weight of this cabinet, it was a cleat -1 x 1 x 15-beveled at 45 One small hole should be drilled in the the rear of the felt necessary to mount wheels to fa- at each end mounted at back panel through which the input top panel 3/4 in. in from the edge -to cilitate ease of handling. lead can he fixed. The removable back provide a screwing surface for the re- At your local hobby shop or wall- can now be placed into position and movable back panel. paper dealer, it is possible to buy decal As shown in Fig. 9, it is wise to screwed securely. veneers, such as "Contact" to dress up caulk all joints with a material such as Figure 10 shows the completed cabi- this cabinet -the final appearance is un- linoleum cement or any compound which net with no speakers, networks, or leads limited, and the more experienced con- will not become brittle with age. It is attached. Be sure to putty in all the structor may take the trouble to veneer very important that all enclosure joints countersunk screw holes. the entire unit in a hardwood finish. .

Fig. 10 (left). Cabinet is com- plete except for trim, finishing, and installation of speaker and network components. At this point it should be thor- oughly solid and non -reso- nant.

Fig. 11 (right). Grille cloth in- stalled in upper section and on front panel. A "picture frame" type of moulding will cover edges of grille cloth. Cabinet may be painted, ve- neered, covered with "Con- tact" decal, or simply left as shown, depending on the de- gree of personal freedom en- joyed by the builder.

AUGUST, 1959 54 AUDIO A FOR EVERY MUSIC LOVER

Whether your requirements are modest or magnificent, there is a fine -music Bozak Speaker System to satisfy every individual need. For Limited Space: The new Bozak "Spinets," quality two- and three -way Systems in compact, functional en- closures measuring only 141/2" x 231/s" x 111/2", that outperform any speakers near their size and price. For Built-ins: Panel- mounted and wired two- and three - way Systems for convenient installation where you want them - in wall, bookcase, or well -made furniture. For the Hobbyist: The easily assembled, acoustically superior infinite -baffle E -300 Kit enclosure, with Bozak's one line of one quality components: the popular B -207A coaxial, the outstanding B-199A woofer, the unique B -209 midrange, the sweet -natural B -200X tweeter, distortion -free crossover networks -and, soon to be announced, the multi -purpose 8" aùxiliary speaker.

For Decor: The industry's widest selection of custom - crafted fine furniture enclosures in Provincial, Urban and Contemporary styling with matching equipment cabinets - choice of fine finishes - or unfinished for special individual requirements.

For Stereo: The original and incomparable single - cabinet dual- matched System -the Bozak B -304 Stereo Fantasy. Or any pair of Bozak Systems. For the Connoisseur: Supreme in realism of music and sound reproduction, the magnificent B -310A and B-400 Systems.

Reward your appreciation of fine music . . . see a Bozak Franchised Dealer for The Very Best in Sound. BOZAK DARIEN CONNECTICUT Errors and Mistakes of Engineers

ALBERT WOODRUFF GRAY

Architects, engineers, and consultants can not usually be held liable for failures in their work -they must exercise due diligence like physi- cians and lawyers, but successful results are not necessarily guaranteed.

OVER A HUNDRED 1V-1128 ago by a New much time to this work as may be re- light of the present knowledge. If the England court was outlined the rule quired. In consideration of being re- plans and specifications were in fact that governs the liability of an en- tained I agree not to engage in con- justified by the common knowledge upon gineer or any other professional worker sulting work for clients in similar or such matters at the time and met the in his performance of services. competitive lines of work." judgment of approval of those men or- "What then is the contract of the pro- Five months later the engineer was re- dinarily skilled and experienced in their fessional man with his employer in re- quested to resign. This he did with the conclusion, the architect has complied gard to his qualifications and conduct," agreement that he would be given two with his contract "* queried that court. "And here it may be months salary in place of the usual no- This charity bestowed by the courts laid down broadly, that without a spe- tice. When the company failed to pay on the honest mistakes of engineers and cial contract for that purpose he is never this advance, suit was brought by the other professional workers in the per- a warrantor nor insurer. He never stip- engineer for the amount he claimed as formance of their undertakings was ex- ulates for success at all events and he is due under his employment contract. tended by a court in the District of Co- never to he tried by the event. As a counterclaim the company de- lumbia a few years ago to relieving an "By our law a person who offers his manded $10,000 for expenses it had in- engineer of consequential damages when services to the community generally or curred which would have been avoided, the correction of the mistake was timely to any individual for employment in any the company claimed, if the engineer had made. professional capacity as a person of skill, properly performed his work as a con- Consulting engineers had been em- contracts with his employer that he pos- sulting engineer. ployed to prepare plans and specifica- sesses that reasonable degree of learning, "It would, I think, be a violent con- tions and on the basis of those plans, skill, and experience which is ordinarily struction of this contract," said the court contracts had been made for the per- possessed by the professors of the same in refusing to recognize any liability as formance of construction work. in the art or science and which is ordinarily re- resting on the engineer under this charge specifications was discovered later a garded by the community and by those of his employer, "to hold that this engi- mathematical error and corrected plans conversant with that employment, as neer intended thereby to guarantee the were immediately prepared. By the court necessary and sufficient to qualify him sufficiency of the plant which was to be in this instance there was charged to engage in such business. "' erected under his care. 1 think a fair in- against the engineers only the additional Even earlier than this pronouncement terpretation of this contract would hold cost resulting from the mistake. by that New Hampshire court is an the engineer to an obligation to assume "The engineers," said the court, "con- English case in which it was asserted, full charge of the construction of the tracted to furnish plans. They did not "every person who enters into a learned work and to use his best endeavor to ac- contract to install the system or guar- profession undertakes to bring to the complish that purpose. "a antee that the system would be installed exercise of it a reasonable degree of care for any specified sum. Through negli- and skill. Charges of Negligence gence they failed to furnish the proper "He does not, if he is an attorney, A very similar situation had been be- plans but when such negligence was dis- undertake at all events to gain the cause fore the Florida courts the year before, covered they supplied supplemental nor does a surgeon undertake that he will but in that instance the charges of negli- plans which together with the original perform a cure. Nor does the latter gence and lack of skill had been made plans filled their contract obligation. undertake to use the highest possible de- against architects instead of engineers. "Had the original plans been free of gree of skill, as there may be persons of There as in the New York decision, the error the cost would have been $183.30 higher education and greater advantages errors or mistakes of the architect in less than in the use of the original plans. than himself, but he undertakes to bring this instance, or of the engineer in the Such amount places the owner in the a fair, reasonable, and competent degree former action, afforded no grounds for same position it would have been in if of. skill. "2 the claim of negligence in the perform- the error had not been committed. A In the circumstances surrounding a ance of the services. larger sum would permit the owner to lawsuit in New York State the humanity "The architect's undertaking," said profit by the engineer's mistake. "5 and justice of this old common law rule the Florida court, does not imply or This feature of the obligations of en- became apparent. There an engineer guarantee a perfect plan or satisfactory gineers, carried a. step further, appeared had written to a company, "I am to act result and there was no evidence suffi- in a recent South Carolina controversy as consulting engineer in your company cient to support a verdict of the exist- in which engineers had obviously failed and to assume entire responsibility for ence of a specific promise or guarantee." to exercise the care and skill demanded the design and construction, devoting as To this statement was added an outline (Continued on page 102) of the legal obligations of a. professional 112-20 72nd Drive, Forest Hills, N. Y. worker. "The law requires only the ex- 4 Bayshore Development Co. V. Bonfoey, 'Leighton v. Sargent, 27 N.H. 460, De- ercise of ordinary skill and care in the 78 So. 507, Florida, March 20, 1918 cember, 1853 ' Henry J. Robb. Inc. v. Urdahl, 78 Atl. ' Lanphier v. Phipos, 173 Eng. Rep. 581, rsulkley v. Kaolin Products Co., 187 2d 387, District of Columbia, January 31, February 16, 1838 A.D.103, New York, March 21, 1919 1951

56 AUDIO AUGUST, 1959 precise Brings The Luxury Of Complete Stereo Within Reach Of Everyone! JtkfELtJt& MARK XXIV The Ultra -New Complete STEREO AMPLIFICATION SYSTEM

Not since the advent of Stereo has any had such unit dra- beauty of design, quality of manufacture . . . and superb matic impact on the world of high fidelity. performance. Now, for the first time, a complete stereo system which in- cludes dual amplifiers and pre -amplifiers in a single corn - Waiting for Multiplex? The INTEGRA Mark XXIV is ready now pact unit ... with sufficient power to equal custom sound to accept Precise Development's accessory MULTIPLECTOR reproduction ... PLUS every important luxury feature found which places Multiplex right where it belongs - inside the in amplifiers sold at twice the price. amplifier! You'll be able to receive Multiplex programs with And, best of all, the Ultra -new INTEGRA Mark XXIV will equal no additional equipment other than your own AM Tuner, FM any stereo amplifier in advanced circuitry, engineering. Tuner or TV.

iQ

A DRAMATIC LINE -UP OF FEATURES: Two Individual Amplifiers and Pre -Amplitiers in a Single Compact Unit 20 Watts RMS Power in Each Channel (40 Watts Peak) 40 Watts RMS Power Combined for Mono- phonic Listening (80 Watts Peak) Ready to Accept In- ternal Accessory MULTIPLECTCR for Immediate Reception of Multiplexed Programs When Used With Your Own AM or FM Tuner or TV Set Separate Push -Pull Amplification Cir- cuits Using 4 Tubes Exclusive Voltage Regulating Fixed Bias Supply Provides 5 Times Greater Efficiency and Vir- tually Eliminates Distortion High Inverse Feedback Cir- Extraordinary New AM -FM TUNER cuit Yields Flat Response from 18 to 20,000 CPS (I db at 75,000 CPS IM Distortion Less Than .6% at Normal Lis- A superb AM and FM providing tening Level Total Harmonic Distortion Less .2% tuner maG:hed per- than at formance and great beauty. Normal Listening Level Separate Treble Controls for Coupled with variable automatic and Each Channel Separate Bass Controls for Each Channel frequency control metered output, it brings in - Separate Volume Controls Each Master the weakest stations and provides razor for Channel sharp Loudness -Control Provides Gain and Attenuation for Both selectivity. Distinctive white and gold front Channels Simultaneously Separate Panel Illumination panel styling. Switch Contour Switch with Provision for Normal Listen - $9995 FM 88 to 108 MC AM 1600 KC Ing,-10 and -20 Slide Switch Affords Stereo, Monophonic - - 500 to Output Tuning Meter Cathode Folower Output AC Convenience Outlet Phono, or Multiplex Listening Plus Mute Position Slide Switch FM, AM, TV Switch Inputs for Phono and TV Foster -Seeley Discriminator for Normal Stereo Listening or Reversal of Stereo Chan- Ready For Flywheel Tuning Two Limiters Ferri -Loop 3-Gang Variable nels Selector Control has Positions for Phono, Tuner Condenser Logging Scale. with Case Listening Tuner Plus TV (for Special TV -Radio Stereo Broadcasts) TV Complete and Tape Built -in Speaker Phasing Variable Hum Bal- ance Control Inputs for 2 Tuners (Can be Operated Si- Superb New multaneously for Stereo Broadcast Reception) Dual Tape 5QlQ,a4 40-WATT Inputs Dual TV Inputs Inputs for Magnetic, Ceramic and Crystal Cartridges Dual Tape Outputs Isolated Heavy -duty AC Power Transformer AC Convenience Out- MONOPHONIC AMPLIFIER let Luxurious White and Gold Contrasting Front Panel A superb 40 -watt amplifier which supports a Handsome Cabinet Tube Complement: Four 6805 sym- phony orchestra with live, crisp, brilliant, distor- (EL84); one 6AC4 (EZ81); one 12AU7 (ECC82); three 12AX7 tion -free reproduction. (ECC83)r one Germanium Diode; one Neon Regulator 24 Positions of Equalization DC on Input Tube Filaments Volume Control Loudness Control 5 my Full Output Rumble Filter $8995 Precise Development Corp. Dept. A -8 Muting O Ide, Long Island, N.Y. Switch AC Convenience Outlet Output Meter Reads Power Output in Watts, Tape Output in Volts Separate and Inde- Please send me information about High Fidelity pendent Tape Output Level Potentiometer Cathode Follower Tape Ready For Equipment. Output Internal Grid Bias, Grid Balance and Hum Balancing Controls Listening Output Selector for Speakers of Different Impedance A -AB -B Name Speaker Selector Special Patent -pending Output Transformer 10 Complete Address Tubes Fused Power Supply . Rich White and Gold Front Panel with Case City Zone State MY DEALER WOULD LIKE INFORMATION TOO1 DEVELOPMENT CORP. He is precise High Fidelity Division Address City Zone State OCEANSIDE, LONG ISLAND, NEW YORK

AUDIO AUGUST, 1959 57 TRANSISTOR MUSIC SYSTEM USING DIRECT COUPLING

(from page 24) used in the common -emitter connection. for a greater range of bass boost than Low -noise operation of Q a PNP type, attenuation and a greater range of treble results from operating its collector at attenuation than boost. only 0.25 volt and 35 pa. Using two PNP When the tone controls are set at their stages followed by an NPN stage allows fiat positions the response is flat within the collector operating point of Q, to be 0.1 db from 10 cps to 100 kc as shown near ground potential which is con- by the lower curve, Fig. 11. As a result venient for the feedback connection to Fig. 12. Square -wave response at the of the gradual attenuation above 100 kc Q,. tape output at the flat setting of the tone the square-wave response, Fig. 12, is Unity d.c. feedback from the collector controls. excellent and exhibits no high -frequency of Q, to the base of Q, establishes a ringing. The phono input is RIAA com- high degree of temperature stability for Both the TAPE OUTPUT signal from the pensated within 1 db from 30 to 10,000 all three stages over the range of 32 to tone -control amplifier and the MONITOR cps. Its response curve, Fig. 13, was 125° F. At audio frequencies the input playback signal from the tape recorder measured at the TAPE OUTPUT with an and feedback networks tailor the re- are mixed at the input of a similar four - ESL C60 pickup playing an RCA No. sponse to the RIAA curve. A s- section stage output amplifier Q Q Q,0, and 12 -5-49 test record. RC low -pass filter at the input flattens Q,,. This section equalizes the speaker Equalization for the speaker system, the phono pickup peak in the 10 to 20 kc response at low and high frequencies by measured at the main OUTPUT with the region and at the same time prevents means of selective feedback. tone controls at their flat positions, is rectification of local radio station car- riers, a serious problem in many loca- tions. 10.000., Following the phono preamplifier four channels are mixed at the input of the d 10 L SPEAKER four transistor tone control section Q4, EQUALIZATION

Qs, Q6 and Q,. Each input has an r.f. 0 VOLTAGE GA N F OM TAPE INPUT TO MAIN OUTPUT filter. This amplifier is similar to the TONE CONTROLS FLAT phono preamplifier except for the addi- tion of an emitter follower Q,. Again direct coupling and feedback are used to 4 VOLTAG GAIN FROM TAPE INPUT TAPE OUTPUT temperature- stabilize the four transis- TONE CONTROLS PFLAT tors at once, determine the gain charac- -let teristics, and provide BASS and TREBLE ''.....\ control action. 10 loo 1000 to 100K IM Stabilization of the feedback at high FREOUENCV IN CYCLES PER RECORD frequencies is accomplished as in the power amplifier by means of local loops Fig. 11. Response at the main output and the tape output at the flat setting of the through small capacitors. In the tone tone controls. control section there is a stabilizing ca- Performance 22 db at 20 cps and 13 db at 20 kc. This pacitor from the emitter of Q, to the response, shown by the upper curve in 10 shows base of Q67 from the emitter of Q, to the Figure the response from Fig. 11, was determined primarily by base of Q4, and from the emitter of Q, the TAPE input to the TAPE OUTPUT. The extensive listening tests using the re- to the base of Q. A 100 -ohm isolating tone -control action and the final com- sponse curves of the woofer and tweeter resistor in series with the TAPE OUTPUT ponent values were determined by listen- measured by a close microphone as jack prevents the phase lag due to line ing tests on a wide variety of program guides. capacitance from causing instability. material. These tests indicated the need As a result of the high feedback factor

Fig. 10 (left). Bass and treble controls balance the response without losing extreme low and high frequencies. Fig. 13 (below). Phono preamplifier and ESL -C60 pickup response.

II 1 1 " ESL RESPONSE TO RIAA INPUT WITH CARTRIDGE .10 MEASURED AT TAPE OUTPUT TONE CONTROLS FLAT

a 0

10

00 0x000 1000o ae 1000 10000 Ioo loop X0°°0 FREQUENCY IN CYCLES PER SECOND FREQUENCY IN CYCLES PER SECOND

58 AUDIO AUGUST, 1959 The world's most sensitive FM TUNER

Nao I And designed for a long future!

FISHER DOES IT AGAINI Year after year, tuner after tuner, there is only one best -THE FISHER. Today, the leader is the FM -100, latest in a series of FISHER FM tuners now used by radio stations, the Satellite Tracking Project of Ohio State University and by many government agencies. The reason is simple - these tuners meet the exacting standards of performance and reliability required by professional users. And where standards are concerned, the audio enthusiast is, in his own right, a professional. He desires maximum sensitivity for optimum reception of stations near and far. FM-100 SENSITIVITY is 0.8 microvolts for 20 db of quieting ! The audio enthusiast wants an FM tuner that permits simple adaptation to stereo. THE FM -100 IS CUSTOM-DESIGNED FOR STEREO. It has space directly on its own chassis for installa- tion of a multiplex adaptor. Moreover, it includes feed -through facilities for FM -FM and FM -AM stereo as well. The audio enthusiast expects maximum fidelity. THE FM -100 OFFERS FOUR WIDE -BAND IF STAGES, uniform frequency response (20 to 20,000 cps) and less than 0.5% harmonic distortion. The audio enthusiast wants an FM tuner that eliminates noise when tuning between stations. THE FM-100 EXCLUSIVE INTERSTATION NOISE SILENCER automatically eliminates noise, side -band response and unwanted weak and noisy signals. For the audio enthusiast who buys the best at the outset, there is only one truly logical choice -IT IS THE FISHER FM -100 TUNER. $159.50 Cabinet, $15.95 Slightly Higher in the Far West.

WRITE TODAY FOR COMPLETE DESCRIPTIVE LITERATURE

FISHER RADIO CORPORATION 21 -29 44th DRIVE LONG ISLAND CITY 1, N. Y.

Export: Morhan Exporting Corp., 458 Broadway, New York 13, N. Y.

AUDIO AUGUST, 1959 59 USED BY PROFESSIONALS:

410

Fig. 15. System acoustic response ALTEC LANSING CORPORA- or with doors open. ¡-""` ,J A AU- TION ANGEL RECORDS ' -10 .1 %A - i DIO FIDELITY RECORDS BEL TONE RECORDING STUDIOS 20 11 CBS LABORATORIES CBS I. RADIOCBS TELEVISION V "0" COLUM- o ,rrr 'WFREOUENCY IN CYCLES PER SECOND BIA RECORDS COLUMBIA PICTURES il: each section of the tone -control pre- from a low -impedance source, is -73 to DEUTSCHE GRAMOPHON amplifier, harmonic distortion is very - 79 db depending upon the control GESELLSCHAFT LONDON low. A 1 -volt rms signal at the TAPE OUT- settings. Since each input will handle 10 RECORDS* MGM STUDIOS PUT, which is 10 db above the normal db more than its rating, signal -to -noise NATIONAL BROADCASTING CO. be level, has less than 0.05 per cent total ratios as high as 83 to 89 db can RCA VICTOR RECORDS RADIO 20 attained. When the master VOLUME con- harmonic distortion from to 10,000 RECORDERS U.S. ARMY U.S. cps control setting. The MAIN trol is turned to zero the output noise at any MARINE CORPS U.S. NAVY U.S. COAST GUARD UNITED NATIONS RADIO VOICE OF AMERICA WARNER BROS. WESTMINSTER RECORDS

Fig. 16. System acoustic response SOLD ONLY BY with doors open. DEALERS, runniammilowLINR9 Microphone at 2 SELECTED feet on center. Ifill11111111111 .1111111111 INCLUDING:

AUDIO- ACOUSTIC EQUIP. CO., DALLAS : IOW 1 0000 D & N DISTRIBUTING CO., INFREQUENCY IN CYCLES PER SECOND NASHVILLE HARVEY RADIO CO., INC., NEW YORK also delivers 1 volt rms from 20 decreases to below audibility at 1 foot output HIGH FIDELITY HOUSE, to 10,000 cps. This level is 8 db above from the speaker. BALTIMORE noise is re- the 0.4 volts needed to drive the power At the phono input the MAGNETIC RECORDERS, amplifier to 20 watts output. Limiting markably low, about - 74 db referred to SAN FRANCISCO at higher output signals is symmetrical a peak velocity of 10 cm /sec at 400 cps. MAGNETIC SERVICE CORP., when the load is 3300 ohms. The absolute level is less than 0.15 ttv COLUMBUS Noise referred to either the TAPE, referred to the input when based on the NEWARK ELECTRIC, CHICAGO RADIO, or Microphone input, when fed 50 -cps gain. RADIO SHACK, BOSTON SANDERS & ASSOCIATES, SANTA FE STEINBERG'S, CINCINNATI STUDIO SUPPLY CO., LOS ANGELES 20TH CENTURY SALES CO., SPOKANE U.S. RECORDING, +10 Fig. 17. System WASHINGTON, D.C. acoustic response VIDEON, INC., HIALEAH o iMIr1121111.lwr with doors as in W & W DISTRIBUTING CO., ..rl111111113111MM1 fIN11! I'11RII Fig. 14. Micro- MEMPHIS phone at 2 feet on 'III19JY1Il IGIhI 10 center. l'II EXCLUSIVE SALES &

20 SERVICING AGENTS IN THE U.S. AND CANADA: 20 ROW 100 I FREQUENCY IN CYCLES PER SECOND

AUDIO AUGUST, 1959 60 IT'S WHAT'S ßIGHT HERE THAT'S ALWAYS COUNTED!

M-49b \ NEUMANN CONTINUOUSLY ELECTRONICALLY VARIABLE DIRECTIONAL PATTERN MICROPHONE SYSTEM

0l411.11 _

KM-54a NEUMANN HYPER -CARDIOID MINIATURE MICROPHONE, DESIGNED WITH TV AND FILM IN MINO

U-47 (U-48) NEUMANN "STUDIO STANDARD" MICROPHONE SYSTEM

KM-56 NEUMANN MINIATURE CONDENSER MICRO- PHONE SYSTEM

COMPLETE TECHNICAL SPECIFICATIONS WILL BE PROMPTLY FURNISHED UPON PROFESSIONAL REQUEST.

otham /''ludio sales co. inc. 2 West 46th Street, N. Y. 36, N. Y. COlumbus 5 -4111

AUDIO AUGUST, 1959 61 Speaker System To produce a smooth musical sound the speaker system incorporates its own reverberation chamber. Two hinged doors Developed and forming an adjustable triangular cham- Guild- erafted ber in front of the closed box speaker by enclosure, Fig. 14, reflect the sound Philips times in a random manner. of the numerous is rather similar ...the Netherlands Their effect in listening to placing the speaker system in a live listening room. The enclosure itself is a 2.3 -cubic -foot ee closed box or infinite baffle completely 0P filled with sound absorbing material. It new line Lansing Model D130 15 -inch rig strramel contains a Construction of woofer and a Jensen Model RP -103 5 -way binding An enclosure posts horn -type tweeter. earlier design used a ducted bass -reflex port. The tweeter and several convex sound reflectors were built into the port which LOUDSPEAKERS then acted as a reverberation chamber for the tweeter. Changing to a closed featuring new Ticona I.7 magnets box and re- equalizing has permitted ex- alloy magnet of úMOo RIcia e tension of the bass range of the entire (30% more powerful than alnico) music system from 80 cps down to 20 Standard E.I.A. cps. The larger reverberation chamber ounting kolas This new line of 5" to 12" loudspeakers is designed to match the quality requirements of the discriminat- formed by the doors produced reverbera- ing music lover ... at a surprisingly moderate price. tion for both the woofer and the tweeter, The world's greatest buys on the basis of listening resulting in a smoother sounding cross- Ao-s277Y quality, the T -7 series incorporates voice coil magnets over. of Ticonal -7 steel, the most powerful of modern mag- Contrary to the present trend toward net alloys, for maximum efficiency and damping ... inefficient woofers in which the middle - dual cones for wide frequency response ... constant impedance resulting in an extremely straight response range efficiency has been lowered to curve ... longer effective air-gaps and extra high flux match that of the bass range, this system density to provide exceptional transient response and uses a woofer having a 4 -inch voice coil to eliminate ringing and overshoot. which makes one of the most efficient A63600M hove Frs,eear, As a of the (nns) tilìnerirl 9.141 flue Response Audi,Mita motors obtainable. result Model Sin (inlalut, real al 40D cps (Mannllil his) Mel high efficiency the bass response falls off 90.52776 6% 12- 20 50 12e.000 25.15.000 572.50 in a nonresonant manner which can be 991.42779 12- 20 10 7% 00000 ]5.11.000 2000 A0.4571M RC 1- 6 0 lo% 50.300 50.20.000 36.00 equalized by the relatively simple 90.750065 0- 6 10 6% 26.200 75.10.000 9.90 feedback network in the output amplifier AD.0500M 5' 3 5 4% 26.200 ]0.10.000 a.24 Flattening the re- A04600M 640- 6 9 5.5% 26.200 of the control unit. AD-2690M 70.11.00 7.0S AD.2600M 6.09 6 0 15% 15200 70.16.000 6.75 sponse by means of electrical equaliza- tion instead of mechanical produces a "'eke 'EXHIBITION' wider bass range and up to 10 db more SPEAKER ENCLOSURES acoustic power output on program ma- terial having moderate bass energy con- Available In three sizes in hand -rubbed Mahogany, Walnut, Blond or Cherry finishes. -The "Rembrandt," (26" x 2142" tent. x 1746" deep) Walnut or Cherry $99.50; Blond $94.95; Ma. A single 10 -µf nonpolarized electro- hogany $91.00. The "Van Gogh," (232/4" x 132/6" x 115/4" deep') Walnut or Cherry $59.95; Blond $55.50; Mahogany lytic capacitor in series with the tweeter $51.00. The "Vermeer," (1842 x 12" x 8- 15/16" deep') comprises the crossover network. The Walnut or Cherry $35.00; Blond $33 25 Mahogany $31.00. system is May be placed horizontally or vertically. average impedance of the about 10 ohms. ...also new from Are/CO Curves of the equalized speaker re- The "HAGUE "; Completely integrated quality speaker sys- sponse, made outdoors with a very close tem.Two high -efficiency T -7 loudspeakers in an acoustically microphone are shown in Fig. 15. For matched enclosure. Designed for optimum dispersion ... maximum efficiency . extremely wide- range, flat re- these measurements the speaker system sponse. 26" x 2142 x 1746" deep. Walnut or Cherry was placed face up on the ground with Blond $154.95; $159.95; Mahogany $149.95. the doors folded back against the sides. A calibrated Altec type 21 -C microphone For further descriptive literature write to: was placed 1/2 inch from the grill cloth NORTH AMERICAN PHILIPS CO., INC. i11 front of the woofer to measure the High Fidelity Products Division, Dept. 3A8 solid curve and 4 inches from the grill 230 Dully Avenue, Hicksville, L. I., N.Y. cloth on the axis of the tweeter to meas- ure the dashed curve. The remarkably flat response of the woofer and speaker equalizer within ±2 db from 25 to 1000 cps indicates that the motion of the cone

AUGUST, 1959 62 AUDIO PACO is the kit division of PRECISION Apparatus Co., Inc., world famous manufacturers of laboratory electronic instruments for over a quarter century. The new Model A new SA-40 is the first of a series of component high fidelity kits from PACO...engineered for utmost performance and last- 40 -watt ing value- designed for maximum eye -appeal. Whether you're an experienced audiophile or a newcomer stereo to the thrill of high fidelity, the factors you must consider Fig. 14. Closed -box speaker system. preamp -amplifier in choosing the amplifier you need are: Doors form reverberation chamber. POWER, DISTORTION, FLEXIBILITY and VALUE. in kit form The PACO SA -40 offers you greater reserve power capacity than any other preamp -amplifier in its category. is well Its excep- controlled in this region. Although for only tional circuit design assures highly stable performance with the system could have been equalized $79.95 extremely low distortion. Step -by -step assembly instructions for flatter response above 5000 cps, lis- and giant -size wiring diagrams are so clearly detailed and simple that tening tests by the technical difference between expert and indicated that further high - novice disappears. And...the SA-40 provides maximum frequency compensation was undesirable flexibility in any stereophonic high fidelity system...present even on live program material. lt-tS Ca or contemplated. For those interested When the microphone is moved to a also in engineering details, some of the more important technical specifications are listed below: distance of 2 feet on the axis of the available speaker system, the measured frequency factory wired for $129.95 POWER OUTPUT: response, Fig. 16, is entirely different. Steady State Power Output: 20 watts per channel, This curve was measured by an equalized 40 watts total. Music Waveform Power Output: 25 watts per channel, type 640AA micro- 50 watts total. phone in the Harvard anechoic chamber. Peak Power Output: 40 watts per channel, Ask your own 80 watts total. A high -pass filter in the measuring sys- Audio -Radio -TV RESPONSE: 30 cps to 90 Kc, ± 1.0 db. tan attenuated frequencies below 50 cps. Serviceman about DISTORTION: Harmonic: Less than .2% at 20 watts per channel output. A peak at 4000 cps in the tweeter re- PACO and PRECISION Less than .1% at 10 watts per channel output. sponse, Fig. 15, has now become a valley products. He'll tell you that Intermodulation: Less than 1% at full rated output. they always live up to their FRONT PANEL CONTROLS AND SWITCHES: 14 controls due to cancellation from the woofer. At including separate bass and treble specs. That's why we can controls for complete 50 cps the response is down nearly 10 db flexibility with any monophonic or stereo program source. say that the PACO SA-40 INPUTS: 14 total; 3 dual high -level and 4 dual low -level. from that at 500 cps. Listening tests is the last preamp-amplifier OUTPUTS: Dual tape outputs. separate preamp output as indicated that increasing you'll ever have to buy well as standard dual speaker outputs. the bass com- HUM AND NOISE LEVEL: pensation to flatten this curve made the Available at leading electronic High Level Input: 80 db below rated output. system sound boomy in most locations. parts distributors and Low Level Input: 70 db below rated output. wherever good sound is sold. Tape Input: 65 db below rated output. The compensation which produced flat SPEAKER CONNECTIONS: 4, 8, 16. 32 ohms. response with the close microphone, Fig. For complete information SENSITIVITY FOR RATED OUTPUT: write to: Aux Input: .75 V Phono 1: (Magnetic) 5 Mv. 15, seemed to be optimum. Tuner: .75 V Phono 2: (Magnetic) 5 Mv.orCeramic.3V As would be expected, partially INVERSE FEEDBACK: 25 db clos- DAMPING FACTOR: 22 ing the doors in front of the enclosure BASS TONE CONTROL RANGE: ±15 db at 50 cps. TREBLE TONE ± as in Fig. 14 produced multiple reflec- Electronics Co., Inc. CONTROL RANGE: 15 db at 10 Kc. 70 -31 84th Street RUMBLE FILTER: 6 db per octave below 50 cps. tions which resulted in a great many Glendale 27, L. I., N. Y. EQUALIZATION: Phono: "RIAA "; "EUR "; Tepe: 344 peaks and valleys in the response, A Division of and 754 ips, NARTB Fig. TAPE OUTPUT LEVEL: 2 volts per channel. 17. Surprisingly the musical quality with PRECISION POWER SUPPLY: Silicon diode, low impedance for minimum this jagged curve is much smoother Apparatus Company, Inc. distortion on extended high level passages. than EXTERNAL DESIGN: Gold and satin black hooded case, with that with the doors open. Export: panel Illumination and satin gold panel. The foregoing techniques Morhan Exporting Corp. DIMENSIONS: 153/4" wide x 113" deep x 5%" high have pro- 458 Broadway Model SA-40: Complete with case and step -by -step duced a compact music system having N. Y. 13, N. Y., U.S.A. assembly- operating manual Kit Net Price $ 79.95 both high performance and ear appeal. Canada: Model SA-40W: Factory Wired Net Price $129.95 Atlas Radio Corp., Ltd. 50 Wingold Ave. COMING SOON MODEL ST-45 REFERENCE Toronto 19, Ontario - AM /FM STEREO TUNER KIT I3urwen, Richard S., "Portable transistor matching companion music system" Journal of the Audio Engi- for the SA -40 neering Society, Vol. 6, No. 1, January 1958, pp 10-18.

AUDIO AUGUST, 1959 63 AUDIO ETC TAKE TWO MINUTES (front page 16) 2. CARTRIDGES In the general enthusiasm for our devel- oping stereo equipment this last spring I TO DISCOVER was given so many new stereo cartridges THE to try out that I ended up more confused than enlightened. Since my "testing" is always strictly practical use and ear-listen- ing, the thing to do was to put these car- tridges to work and see what happened. I SOUND BEYOND hooked them all up into my interchangeable plug-in (four -wire) system, tried a couple in a changer, as well as in a manual turn- table set -up, and went about my business of playing records by the dozens -and lis- CONVENTIONAL STEREO! tening, not to the cartridge but to the music. That's what counts, after all. going to have to beg off any detailed (Reading time: 2 minutes) I'm report on each one of these numerous ex- Now ... after years of intensive lab- cally illustrated by its space- saving size. cellent stereo cartridges; there were too oratory research and development, comes The entire system blends beautifully with many for my ears. I'll offer a few generali- zations, though, plus a few side -comments revolutionary new in your favorite decor and fits any size a advance the field on one or the other, and hope that the of stereo. TRIOPHONIC STEREO, the room. So light -in- weight you can easily persevering cartridge makers will forgive sound that outmodes conventional stereo, carry all the components home yourself. me for having only one set of ears. was created by the electronic engineer- Weathers TRIOPHONIC STEREO is ing know -how of Weathers Industries! truly a miracle in both sound and size! GE Electric is one up on me -the Through the miracle of TRIO - Here's what the "Home Testing Lab- General company has brought out a new stereo PHONIC STEREO, the listener expe- oratory" of MUSIC, U.S.A. recently cartridge, the VR -22 type, before I so riences "Equalized Sound ", an amazing wrote in describing the outstanding per- much as got around to discussing the first new audio dimension enabling you to formance of Weathers TRIOPHONIC one. I haven't seen the new model but I hear the same tonal clarity and quality STEREO: gather it is an outgrowth of the earlier design rather than a wholly new departure full range sound (30- 15,000 cps) any "As we walked into the room, we were of in cartridge construction -so perhaps my place in the room ... you are no longer immediately conscious that we had entered remarks herewith will apply to the whole a "captive audience". "Equalized Sound" a new realm of sound': This was the same present GE stereo lino of cartridges. is produced by Weathers Harmony Trio kind of bass quality we'd heard before in What I have to say is simple enough. magnetic cartridge has from the never through play- The GE speaker system which includes two book live performance, but beginning been aimed at a very specific size full range stereo speakers and a non- back reproducers -especially through place in the phonograph world and has been directional hideaway bass. speakers the size of these midgets ". tailored with exquisite care to fit its basic purpose simple, efficient, mass -produced wonderful practicality of Weathers Write to Dept. A for FREE book- -a The cartridge that in volume production can TRIOPHONIC STEREO is dramati- let on the full TRIOPHONIC story. give a maximum value at a minimum price. It takes a very large company to swing a project of that sort and GE has the size and the umph to do it. But as we all know, the larger a mass- production project gets, the more crucially important are the exact details of the manufacturing process. Such a product is 90 per cent designed around production -quick, simple manufacturing. The most minute details, even down to the diamond point itself, must be planned for K-601 ° SE-50 SE -66 volume operation. The tiniest miscalcula- SteroRamic Record Player Harmony Stereo Speakers The Hideaway Basa tion, from this special viewpoint, can spell disaster on a relatively huge scale. It has been GE's purpose and GE's ac- THE SOUND OF TOMORROW, TODAY! complishment through these years to achieve maximum cartridge value in these very special ternis, as I see it. The inten- tion is utterly different from that of a cartridge such as, say, the Grado, which is deliberately designed for top excellence on an individual basis, virtually hand -made. SEE IT... HEAR IT... COMPARE IT... TO BELIEVE IT! These differences in emphasis are little known to the general public but every man- ufacturer knows them all too well. The very WEATHERS INDUSTRIES, 66 E. Gloucester Pike, Barrington, N.J. first consideration in every piece of manu- Division of Advonce Industries design must be to choose the Emport. Joseph Plasencia, Inc, 401 Broadway, New York 13, N. Y. facturing

AUGUST, 1959 64 AUDIO exact area of contemplated production and shoot precisely for it, down to the last screw and wire and hunk of solder-if any. With this prelude, it seems to me that we can look at the GE cartridge and see AMPEX 351 precisely where it stands -today as in the STEREOPHONIC past. There was much initial criticism of / MONOPHONIC the GE stereo on the glaringly obvious ground that the stereo model used basically the same two coils as the mono version before it and thereby sacrificed the obvi- ously valuable hum- bucking qualities of the double -coil arrangement. Does anybody think GE didn't know this? Don't be silly. Of course the GE de- sign people knew all about it (or they wouldn't deserve a grade -school diploma in elementary science). But the likely alterna- tive, a double -double -coil design, four coils and dual hum -bucking, was one of those fatal traps that GE unerringly avoided. In the GE -type operation, this was just plain out of the question. The added cost would simply kill the basic concept of the car- tridge, which is a simple product to sell at a fabulously low price in huge volume. Perhaps you'll remember the Model T Ford and the old Ford idea that the $300 auto could be painted "any color so long as it was black." Without implying any direct comparison between GE and Ford T, I suggest that the old Ford concept was just as delicately calculated as the new GE THE cartridge concept and that, in the old days, STANDARD THAT SAVES DOLLARS the addition of rainbow colors to the Since its introduction, the Ampex 351 Series has model T would been acknowl- have been basically just as edged as the standard of excellence in professional recorders for costly, as prohibitively uneconomical in the the manufacturing, broadcast industry. Broadcasters -and other users with as the use of double highly critical recording requirements, coils in the original GE stereo such as recording studios model. After and educational institutions find all, how much Ford do you buy now -will that the purchase of an for Ampex 351 is further justified by these $300 -or $600, taking account of the dol- important facts: lar's change? The recognized precision and engineering skill which go into Moreover, I suspect, and believe, that each Ampex 351 guarantees unsurpassed durability and reliability GE did sonic marvelously careful calculat- for a long, dependable life. As a result... on a cost- per-operating- ing on this hum problem. It was a risk, a hour basis. Ampex is the most economical of any recorder made. neatly calculated one. I think I can get away with saying that the first GE stereo PERFORMANCE SPECIFICATIONS cartridge did, indeed, as I used it myself, Note: As professional equipment, the Ampex 351 specifications listed are pick up stray bum noticeably more easily accurate measurements required by NAB standards and do not incorporate than other cartridges, in the very same sit- any exaggerated sales claims. These are the guaranteed minimum performance specifications the customer uations. Just move a hefty motor or a can expect in long -ronge operation. sizeable transformer somewhere near that Frequency Response: 15 ips ±2db 30 to 15,000 cps cartridge and the hum rises up as clearly 71& ips ±4db 30 to 15,000 cps as you please. No two ways about it, the ± 2db 40 to 10,000 cps cartridge obviously was susceptible -is Flutter and Wow: 15ips -well below 0.15% RMS susceptible -to a good deal of hum pickup. 7h ips -well below 0.2% RMS Timing Accuracy: Within But liete does it work out in. practice? ±0.2°/0 ( ±3.6 sec. in a 30 min. recording) Starting Time : That is the real question. Full speed in less than 1 /10 sec. Stopping Time: At 15 ips, tape less It works out generally moves than 2" after pressing as GE must have "Stop" button. predicted- pretty darned well. As recon- I Models: Half track, full track, 2 track stereo (separate erase struct it, this must have been the sort of to each track). Console, portable and rack mount. canny thinking that went on chez GE. 1. The cartridge picks up hum, but in FULL REMOTE CONTROL most situations it won't pick up enough to The Ampex 351 Series can be operated in bother the average GE user, in all his the relay -solenoid tape motion control unit m :iIlionns. for Start, Stop, Fast Forward, Rewind and 2. The phonograph makers who install Record modes from any remote location. GE cartridges themselves at the factory- - There are 185 Ampex dealers to a major intention of such a cartridge- serve you. Check the Recording Equipment listing in the yellow pages will be able to solve the hum problem rea- of metropolitan area directories, or write Dept. 304 for sonably well in advance of sale. AN PIEX the name of your neorest dealer. CORPORATION 3. Most home listeners are conditioned, 934 and accept, a certain minimal hung. Them's CHARTER STREET REDWOOD CITY, CALIFORNIA professional Offices and representatives in principal treasonable words, I admit, cities throughout the world. products d i rision and they are .. ., r .

AUDIO AUGUST, 1959 65 mine, not authorized by GE. It's just what sidewise with no measurable friction and I think GE must have thought, in its pri- the point pressure exactly regulated to an DYNAKITS vate calculations. But the premise is valid, unchanging and rock -solid 3 or 4 grams. if unpalatable. People do accept hum, be- But how often, my friends, do we achieve Look Best - Test Best - Sound Best cause they've always had a good bit of it this ideal in practice t around. I am astonished again and again I found that my Stereotwin would pro- at the hum level in various commercial duce clear musical sound at fantastically NEW STEREO 70 KIT -some of them right on the low stylus forces -but thanks to the many dealer's floor. (One was set up for demon- complications we run into the total arm - stration ill the main central office of a and- record assembly, at these delicate pres- huge national electric company. The com- sures it often skipped grooves, or repeated pany engineers with me at the time hastily grooves. Not the cartridge's fault, basic- disclaimed responsibility ; it wasn't their ally, but-shall I say -the situation. Es- department.) pecially in changers. 4. This is a really solid premise: There But when I increased the stylus force a may be practical hum problems here and bit, the Stereotwin's stylus hit bottom there, but technological progress in other (top, more correctly) and buzzed against components will work to GE's advantage its protecting shell. and can be relied upon ahead of time. The leeway, in my particular model, GE could realistically count on steady between a pressure so light as to skip * Dual 35 watt super-quality improvement in the radiation of hum from grooves and so heavy as to cause stylus Amplifiers -70 watt continu- motors and transformers, in all the mi- bottoming on the shell, was uncomfortably ous monophonic rating-160 nutely ingenious ways that good design close. With a larger protective shell, the watt peak engineers can apply their skill to the stylus would have more room for displace- * All critical parts on prefabri- steady bettering of a manufactured prod- ment and could take a slightly greater dis- cated printed circuit assembly uct. Time, definitely, would favor GE. tortion without hitting the shell -at a reduces wiring time to five 5. And meanwhile, GE itself would work greater risk of damage. hours on improvements of its basic design, via I would not want to apply my particular experience and experiment, improvements experience to all Stereotwin cartridges * Premium quality parts con- that could further whittle down the calcu- since my stylus may have been bent or loose servatively operated permit lated risk without tossing out the basic or something else, and I understand that one year guarantee cartridge concept. the newer version -the 210 -has this * Uncompromised design for trouble corrected. But the general princi- finest performance - usable That's it, folks, I'm all for GE, then, ple is an interesting one, and I refer you as with all speakers and in fact while I was away I hooked up a comparison to the Shure stereo cartridges, my original and early GE stereo cartridge which have a similar protecting half -tube * Only $99.95* net including all in a Glaser -Steers changer for my relatives construction that is, however, larger and parts, instructions, and pro- who took over my house for some weeks. It further away from the stylus itself. Also to tective cover sounded just fine and there wasn't a trace the Stereodyne, from Dynakit. But -the of hum to be heard. Well, almost not a pay -off is that both of these cartridges Step up to STEREO trace. have suffered damage under the Canby pro- gram of Rough Treatment. Superb Dynakit Quality Is Fully Com- Stereotwin The Shure M3D, my most -used cartridge, patible With Stereo Requirements developed a permanent list to one side one mild and still unsolved prob- Only after a few months -and I won't try to lem with this useful German cartridge im- tell you how I did it ; I don't know. But list port. The rugged stylus assembly is of the ..- it did. However, the stylus tip did not hit .. type where the stylus arm is set in a pro- at any point. And an open the protecting shell tective shell, a kind of half- circle, and the tube extending out beyond the diamond tip. thanks to the great compliance old -fash- This is fine insurance against the fright- traction arrangement, like an eningly -easy bending of the stylus that can ioned trolley car pole on its wire, the * Famous Dynakit Preamplificrs- quickly occur in these ultra -compliant Shure stylus tends to straighten out in the distortionless and noise free so - days. The fact that the whole assembly playing and tracks more or less where it stack harmoniously for stereo. of the list that shows up $34.95` each pulls out of the cartridge is additional in- ought to, in spite surance-in case the stylus is forcibly when you look at it. The sound, to the best * Add DSC -1 Adaptor unit for com- hooked into some unyielding surface such of my knowledge, is unaffected. plete flexibility. Includes blend, as a turntable mat. The thing just yanks My Stereodyne cartridge from Denmark balance, dual volume controls plus had an even larger protective shell around loudness, tape monitor, and re- out, and remains undamaged, compliance or no. the point -so large that the complaint bar versing switches. Useable with in my most high quality preamplifiers. My trouble with the Stereotwin was in that one was bent really haywire Only $12.95* net. simply in the fact that the half -tube pro- first weeks of testing, to the point where I is small, close to the did not care to use it on my good records. * PM -2S Panel mount kit provides tecting shell and stylus itself. There is very little leeway for My assisting engineer tried to straighten integrated handsome appearance and broke the thing off in the plus mounting facility -$5.95 net. play, either sidewise or vertically. Now I it out don't mean to imply that the stylus can't process. * CM -2S Cabinet Set includes However, don't draw conclusions from walnut table top move the full width and depth of a stereo front panel and as we all this experience since there have been cabinet. $17.95* net. groove -of course it can. But know, arm pull tends to displace a stereo changes in this Stereodyne stylus since I a Available from leading Hi -Fi dealers everywhere. stylus to one side, even with the best of got my early model. No point in judging via an assembly that is no longer in Descriptive brochure available on request. care in the equipment. And, more vital, stylus in the stylus force applied production. I'll tell you later about the rest Slightly higher in West variations like displace the point rather largely of the Danish Stereodyne, which looks from above and vertical sense. Everything's fine when a rocket about to take off at a tangent, INC. in the priced car- DYNACO the record is perfectly flat, the table pre- is an excellent and reasonably 4, Pa., U.S.A. I've tried. 617 N. 41st St., Phila. cisely flat, too, the arm utterly free to move tridge, one of the nicest

AUDIO AUGUST, 1959 66 PRODUCT PREVIEW

A look into the future at the products you will find on dealers' shelves during the coming months -some brand new, some being items intro- duced within the past few months, and some continuing their year- after- year of success derived from reliable performance and user satisfaction.

WHAT STARTED OUT to be an expanded NEW PROD - listing prices in NEW PRODUCTS items because this UCTS section for this month completely exceeded PRODUCT PREVIEW is more in the nature of a catalog. our expectations as to size. And while the six- You will be able to use in it planning additions to your teen pages originally intended to include all of this present system or for planning a complete new system material is well filled up, with more than nine columns for yourself or for someone else. We believe you will of runover commencing on page 105, we still have not find it useful as a reference all through the next year. covered the entire field. The entire group of phono- Since this is a catalog -type presentation, graph pickups it must be and arms has been held over to provide remembered that the statements made about for another the vari- section in the September issue -not, per- ous products are not the result of our own testing, haps, as but large as this one, but in the same general style are the specifications as furnished by the manufac- and completeness. turer. And if you find some manufacturer not repre- On the subject of completeness, it is obvious that sented here although you know he makes products in every product of every manufacturer cannot be pic- the specific categories, you may tured assume either (1) that and described -it would more than cover all the we may possibly have mislaid the material pages sent to us of this relatively large issue and still have plenty for this section, in which case it will appear next left over. We have tried to cover some products from month, or (2) the manufacturer did not send us the each manufacturer -choosing those the manufacturer information requested, or (3)- perish forbid -we himself wished to stress, or in some cases, just using overlooked that manufacturer completely when we sent our own judgement as to the most important items. In out the requests for information. addition to the products pictured and described, sev- We are sincerely grateful for the co-operation eral other given items have been listed following many of the us by all the manufacturers represented. Without their descriptions, which makes this section one of the most concerted help we could not have prepared this ma- complete ever carried in a monthly magazine. terial. We trust you will find it interesting and in- We have departed from our usual custom of not formative throughout the year.

AMPLIFIERS and PREAMPLIFIERS For ACROSOUND either low- or high -power operation. the work for "three -channel" stereo. Circuitry In- Ultra -Linear II is unexcelled. Aero Products, cludes feedback -type equalization plus feed- Ultra- Linear 60 -Watt Power Amplifier KU. 369 Shure Lane, Philadelphia 28, Pa. User back around all tubes for minimum The Ultra -Linear net distortion. II meets the performance price, $79.50. Assembled, $109.50. All low -level tubes have d.c. on heaters. specifications of the most Four- demanding profes- Stereo teen Inputs include two each for magnetic sional application or the most discriminating 20 Self- powered 20 -w ampi. Kit $44.50. Stereo 20A Satellite 20 -w ampi. Kit $29.50 cartridge, ceramic cartridge, tape head, tape music lover. Embodying the well -known Stereo 20-20 36 recorder, tuner, microphone, patented Ultra Linear -w stereo ampi. Kit $69.50 and multiplex. circuit, it delivers full Frequency response is 20 to 20,000 cps +1.0 output with less than 1.0 intermodulation at db at 25 -watts output ; 10 any standard combination to 30,000 cps +0.5 of test frequencies. ALTEC db at 10 watts. Harmonic distortion is -less Stereo Amplifier -Preamplifier. This latest than LO per cent. Tone controls are ganged addition to the Altec-Lansing line of high and provide 14 db of boost or cut at 50 and fidelity equipment, Model 353 -A, is a com- 10,000 cps. Rumble filter attenuates at the plete amplifying system, embodying two 25- watt stereo channels which may be combined for 50 -watt monophonic operation when de- sired. Among its features is a matrixing net-

CONTENTS w Amplifiers and Preamplifiers 67 Harmonic distortion is less than 1.0 per cent AM, FM, and Stereo Tuners 71 at any frequency between rate of 12 db /octave below 30 cps. Silicon 20 and 20,000 cps rectifiers at output within 1.0 db of 60 watts. Fre- Loudspeakers 74 are used in power supply. Engineered quency response is within 1.0 to the professional standards of other Altec- db from 18 to Lansing 30,000 cps at full output. Square -wave re- Record Changers 79 equipment, the 353 -A meets every sponse is entirely without distortion for all criterion of the most discerning music lover. practical purposes from 20 to 20,000 cps, with Phono Turntables 81 Altec Lansing Corporaton, 1515 S. ]Blanchester no overshoot or ringing. Ave., Anaheim, Calif. User net price, $199.50. Rise time of wave is Tape Equipment 1.5 microseconds. Damping factor is variable 82 355A "Quartet" from 20 w mono ampi $111.00 0.5 to 10. Damping control may be Tape Accessories 350A 100 w mono ampi 171,00 switched out to provide a fixed damping 110 440c Mono preamp 147.00 factor of 15. Hum is 90 db below 60 watts. Miscellanous 345 60 w stereo ampi 270.00 111 445A Stereo preamp 189.00 AUDIO AUGUST, 1959 67 tying system providing two 30 -watt channels output. Hum and noise level is more than 90 watts of output for mono- db below 35 watts. The use of prewired printed ARKAY for stereo use, or 60 instructions phonic operation. Harmonic distortion is under circuitry, detailed step -by -step Stereo Preamplifier- Amplificr Kit. A com- Frequency response and pictorial diagrams, enables even the offers ex- 1.0 per cent at full output. plete audio control center which 20,000 cps within 0.5 db. Featuring novice kit builder to construct this amplifier Arkay CS -28 is 20 to ceptional performance, the many engineering refinements, the DB230A with complete confidence. Average construe- matches advanced engineering with excellence selector control for handling Founda- has a six- position of design which won the Fashion inputs for tape. phono cartridge, tuner, or tion's coveted Gold Medal award. Identical

auxiliary equipment. The unit has vol- tion time is about five hours. Dynaco Inc., 817 easily be converted to other 14 -watt amplifiers may ume, bass and treble controls and two hi -lo N. 41st St., Philadelphia 4, Pa. User net Reverse- 28 -watts for monophonic operation. filter switches. Special features are the Bogen price, including protective cover. $99.95. stereo switch Interchanges channels when which eliminates each "Speaker Phasing Switch," desired. Balance control compensates the effect that sometimes Mk II 50 w ampi kit $69.75 and room acous- the "hole-In- -middle" Mk 60 w ampi kit 84.95 channel for speaker systems in stereo reproduction, a loudness con- Ill both channels occurs Mk IV 40 w ampi kit 59.95 tics. Gain control operates selector for levelling out frequency re- 34.95 the front -end facilities, tour Preamp kit, mono simultaneously. All of sponse at low volume, and a control for balanc- Stereo control kit 12.95 including tone controls, are available at the plus a channel -reverse kit 8.95 For tape ing the two channels Preamp power supply dual preamp output connectors. Bogen- Presto Company, a Division of tone controls are by- switch. recording loudness and The Siegler Corporation, Paramus, N. J. User passed by means of a panel- mounted switch. EICO within net price, $189.50. Frequency response Is 20 to 20,000 cps Amplifier Kit. This new and harmonic dis- Stereo ampi $119.95 Low -Coat Stereo + 1.0 db. Intermodulation D B212 24w Eico brings full stereo performance 1.0 per cent at rated out- amplifier tortion are under to even the most budget -minded music lover. put. Tone controls afford 16 db boost and Hum It is engineered to provide true bi -fi quality cut at 50 and 10,000 cps, respectively. DE WALD which are adequate for driv- db at low -level power levels and noise level is down 70 speakers to concert volume. Kits, Inc., 88-06 Van Wyck Fifty -Watt Stereo Amplifier. Although ing high -efficiency input. Radio Model N -2200 "Classic" The input selection, mode of operation. tone Expressway, Jamaica 18, N. Y. User net modest in cost, the a complete stereo control system and level controls insure complete flexibility price, in kit form, $64.95 ; fully wired, $99.95. embodies and two power output channels with a com- of operation. The AF -4 employs a moderate FL -30 Ampl- preamp 49.95 bined continuous -power rating of 50 watts. single- ganged tone control so that available -12 20w stet ampl -preamp 36.95 are separate equal- gain. released by this type of control. is con- CS 49.95 Included among features SPA -36 40w stet ampi ization, selector, and mode controls offering verted into distortion -reducing negative feed- the user full flexibility of operation. Tape - BELL monitoring and tape -output jacks permit Stereo Amplifier. Developed for stereo from input to output, the Bell "Carillon" Model 6060 is conservatively rated at 30 -watts out- put for each channel, with 60 watts of mono- phonic power available when needed. Fre- quency response is stated by the manufacturer to be 15 to 30,000 cps ± 1.0 db. Hum level is 71 db below rated output. All operating con- trols of the 6060 are conveniently located across the front panel. Bass controls permit 15 db rise and 18 db droop at 50 cps ; treble - back. The problem of distortion, created where rise and 18 db droop at controls afford 9 db direct tape recording with complete control available gain is expended on severe bass and of volume and tone. Individual bass and treble treble boost, is thereby avoided. The feedback controls are included for each channel. Sixteen level around each power amplifier is 27 db. input jacks mounted in the rear of the am- which results in intermodulation and har- plifier are isolated from each other so that monic distortion figures, taken at average any or all of them may be used at any time listening levels, which fall well within high - without interference or signal loss. Output fidelity standards. Front panel controls are: circuitry utilizes four EL -86 tubes, with re- input selector, mode, level, tone, and on -off. intermodulation being well under 1.0 Five pairs of inputs are provided for low - sultant service- per cent at full output. De Wald Radio Divi- and high -gain program sources. A sion United Scientific Laboratories, Inc., selector switch permits parallel or separate of stereo 33-15 37th Ave., Long Island City, N. Y. operation of the power amplifiers for net price, housed in an attractive black or monophonic use, respectively. Exact engi- User not available at panel picture -frame case with brushed -brass face neering specifications were 10,000 cps. Also located on the front Electronic Instrument Co., Inc., lever-type switches which provide plate, $189.95. press time. are four 33-00 Northern Blvd., Long Island City 1, filter cut -off (to S 99.95 high- and low -frequency N -1200B 30w comp stet ampi net price, in kit form, $38.95 ; rumble), stereo function N. Y. User eliminate hiss and factory wired, $64.95. control, and speaker selection for stereo in more than one room. A separate balance con- HF81 stet preamp -ampi the volume level between two DYNAKIT kit, $69.95 ; wired, $109.95 trol adjusts wired, $64.95 stereo speakers. Continuously -variable loud- Power Amplifier Kit. This am- HF85 stet preamp .. kit, $39.95; "Stereo 70" HF30 pwr ampi .... kit, $39.95; wired. $62.95 ness control compensates for bass and treble plifier kit is designed to meet the needs of the at low listening levels. Dial frame is extruded discriminating listener for a moderate -power aluminum, while the panel has all the letter- high- performance power amplifier. Engineered FISHER ing etched for clarity. Vinyl tan cover is and monophonic opera- for both stereophonic Control. There is no set off by the perforated thermal duct which tion, the Stereo 70 incorporates two 35-watt Stereo Master Audio ventilation. Bell Sound Division, means of more versatile preamplifier- control unit than provides channels which can be paralleled by remote Thompson Ramo Wooldridge Inc., 555 Marion 70 watts of the Fisher Model 400 -CA. Capable of a convenient switch to provide Fisher RK -1 Road, Columbus 7, Ohio. User net price, output. The high power capa- operation when used with the single-channel it contains 16 input jacks $219.95. bility and low internal impedance of the remote control unit, damping for all for any combination of stereo or monophonic 14w ster ampi $ 69.95 amplifiers provide excellent are provided 2212 "Pacemaker" speaker systems, in- application. Four output jacks 2221 " 20w stet ampi 99.95 types of high fidelity bass and types, without need and a total of 11 controls -including 2215 " 10w ampi 55.00 cluding the low-efficiency independent regu- for individual adjustments. Frequency response treble controls to provide of each channel, or ganged control of is + 0.5 db from 10 to 40,000 cps ; power re- lation BOGEN- PRESTO exceeding both channels-provide a shading of adjust- sponse-20 to 20,000 cps without music within 1.0 db of 35 ment to satisfy the most demanding Amplifier-Preamplifier. The new 1.0 per cent distortion is from 20 Stereo is volts rms for 35 watts lover. Frequency response uniform Bogen Model DB230A is a stereophonic ampli- watts. Sensitivity 1.3 AUDIO AUGUST, 1959 68 to 25,000 cps. Distortion is less than 0.15 per quency response cent for 2 volta output; less than 0.3 per is 20 to 20,000 cps ± LO db ; cent for 5 volts output. Hum and noise 15 to 35.000 cps +1.5 db. A complete com- level plement of controls is down 65 db for 10 -mv low -level input and 2 -including remote balance volts output. control on 20 -ft. extension -permits every Crosstalk between channels is desired down more than 65 db. Cathode -follower re- stereo function. Construction is greatly simplified through use of printed circuit

control, permits variation of input to stereo speakers. Push-button switches are used for rumble and scratch filters, to disable loudness control compensation, and for switching power on and off. Tone controls provide 15 db of boost or cut nt 50 and 10,000 cps. The 28PG boards. Heath is fused and contains Company, Benton Harbor, two convenience outlets. Mich. User net price, SP -2 Moderate in price, it offers an Stereo Preamplifier, unexcelled $56.95 ; SP -1 Monophonic Preamplifier, combination of fine performance at moderate $37.95 ; C -SP -1 Conversion Kit, $21.95. corder output, and low- cost. Precision Electronics, Inc., 9101 King impedance output to St., Franklin WA -P2 preamp, mono amplifier-speaker system, permit output cable Park, Ill. $ 19.75 length EA -2 12w ampi 28 »5 of 100 ft. without impairment of sig- W -7M 55w ampi 54.95 nal. D.c. is used on all heaters. Four switched auxiliary a.c. receptacles on rear apron furnish up to 650 watts for associated equipment. The HARMAN -KARDON KNIGHT -KIT 400 -CA will meet every demand of the most discriminating Stereo Amplifier- Preamplifier. The "Ballad" Knight -Kit 40-Watt Stereo Amplifier. Both connoisseu r. Fisher Radio Model A230 is a new economy Corporation, 21 -21 stereo amplifier incor- and impressive performance are com- 44th Drive, Long Island porating dual preamplifiers and bined In the Knight -Kit City 1, N.Y. User net price, $174.50. dual 15-watt 40 -watt stereo am- power amplifiers on n single strikingly hand- plifier, a complete preamplifier and power 101A 40w ster preamp -ampl 194.50 some chassis. It operates under the most con- amplifier on a single chassis. Two 20 -watt 30C ream servative conditions, including self -bias of the channels may be paralleled for monophonic 400CA ster preamp 174.50 output tubes, assuring long trouble -free per- operation when desired. Frequency response SA -300 60w ster pwr amp' 169.50 formance. The power amplifiers have instan- taneous recovery time, resulting in clean and faithful transient response. Among features of the Ballad are friction -clutch tone controls GENERAL ELECTRIC which adjust bass and treble separately for "Stereo Ciaaeic" Amplifier. The G -E Model MS -2000 is an integrated unit combining a high -quality stereo preamplifier with matching power amplifiers on a single compact chassis. Notwithstanding its moderate price, it leaves nothing to be desired in audio performance. Power output is 28 watts. 14 watts per chan- nel In stereo operation. Frequency response is 20 to 20.000 cps ±0,5 db at rated output; is 15 to 35.000 cps ± LO db at 10 watts out- distortion is below 1.0 per cent. Hum and put. In addition to offering all conventional functions for 2-channel stereo, this unit pro- vides a unique third, or "center channel" each channel and lock automatically to pro- output which permits feeding full-range pro- vide the convenience of ganged operation. gram material to a center speaker for elimi- An exclusive speaker selector permits the op- nation of the "hole-in-the-middle" effect, or eration of a third speaker as a "center chan- for feeding an extension speaker for mono- nel" in a stereo system, and it also per- phonic listening. Bass and treble controls offer mits a remote speaker to be used mono- 15 -db boost and droop at 20 and 20,000 cps, phonically at the same time. All are selectable respectively. Among other advanced features by front panel switches. Additional features are printed circuitry plus printed-circuit include : illuminated push -button on /off switch switches for ease of assembly ; dual -concentric which permits the amplifier to be switched on clutch -type tone controls for individual or or off without disturbing control settings; simultaneous adjustment of the two channels, noise level is down 55 db and 73 db on low - special tape outputs unaffected by loudness and switch -controlled Fletcher and -Munson -type high -gain inputs, respectively. Channel and tone controls ; speaker phasing switch; loudness control. Harmonic distortion is less separation Is contour ; better than 40 db over the entire switch balance control ; mode switch ; than 0.5 per cent at rated output. frequency range. function Allied Full -wave selenium rectifier selector switch ; rumble filter ; im- Radio Corporation, 100 N. Western Ave., reduces heat. Front panel controls include pedance selector switch. Frequency response Chicago 80, Ill. User net price (approximate), rumble filter and continuously- variable loud- is stated by the manufacturer to be 15 to $80.00. ness contour adjustment. Tone 70,000 cps ± 1.0 db controls are nt normal listening level. 20w stereo ampi of the variable turnover Baxandall type. The Harmonic distortion is less than 1.0 per cent $44.50 MS -2000 is compact for nt full rated 60w stereo pwr amp! 84.50 all its power output, output. Harman- Kardon, Inc., Stereo preamp 62.50 measuring 5y. "I1 x 15 "w x 12 "d (less knobs). 520 Main St., Westbury, N. Y. User net price, The cabinet is finished in leather -grain gray less enclosure, $109.95. vinyl. Front panel Is finished in LEAK darker gray A220 "Lute" 20w ster amp! 79.95 with satin silver trim. General Electric Com- pany, Audio Newly-Styled "Point One" Stereo Preamp. Components Products Section, Impressive new styling West Genesee St, Auburn, N.Y. User net enhances the appear- price, $129.95. ance of the latest version of the well-known HEATHKIT Leak "Point One" stereo preamplifier. Deco- MS -4000 40 w ster ampi $179.95 rator- designed, the new front panel offers RG -1000 Remote stereo control 14.95 Mono- Stereo Preamplifier Kit. This kit is changeable color panels for both faceplate intended for those who wish to build a top - and knobs, enabling the user to match the quality monophonic preamplifier now, with an decor of any room. The new escutcheon plate eye toward converting to stereo in the future. is interchangeable with the present one, per- GROMMES It is available in three distinct kits. It may mitting present owners the option of inez- be purchased as Model SP -2, a complete versa- Twenty -Eight Watt Stereo Amplifier. The tile stereo new Grommes preamplifier ; or as Model SP -1, a Model 28PG is complete In high- quality monophonic preamplifier, which every respect, incorporating a full set of may ganged be converted to stereo bg means of the controls, two preamplifiers, and two Model CSP -1 14 -watt power amplifiers conversion kit. To make the that may be switched conversion, no rewiring is required to the al- to 28 watts of monophonic power when not using ready existing monophonic channel. The con- stereo sources. Low -heat silicon recti- version kit is fiers are used in simply wired and plugged into the power supply. Frequency the SP -1 chassis, which is designed to accept response is within ± 0.5 db from 20 to 20,000 the additional cps. Harmonic distortion equipment. The control shafts is less than 1.0 and plug directly through the channel A control intermodulation is under 2.0 per cent at full knobs, allowing rated output. Ten inputs concentric operation of chan- accommodate virtu- nel A and channel B controls. Six inputs are ally any type of signal source. Along with all provided conventional adjustments, for each channel -tape, magnetic a channel- balance phono, microphone, and three auxiliary. Fre-

AUDIO AUGUST, 1959 69 A and high frequencies to Channel pensive conversion to the new styling. The right speaker only; left channel on both speak- Channel and right channel on both speakers. For 13 for monophonic bi- amplifier use. Frequency "Point One" includes provisions for playing ers, Harmonic channel only, right monophonic operation, the C -20 internally response is 20 to 20,000 ±1.0 db. stereo, stereo reverse, left is 0.2 per cent below maximum channel only, and monophonically. There are parallels and decouples a stereo pion car- distortion virtually any type of tridge to provide best possible reproduction sensitivity. Audio output is 1.0 volt. Hum and five dual inputs for down 80 db. Professional in stereo or monophonic source, including micro- from monophonic records. A 2- position high - noise level is frequency cut -off control (9 and 5 kc) is pro- both design and performance, the 216 -A will phone. Bass and treble controls permit boost home music and 15,000 cps, re- vided for suppressing hiss. Rumble filter re- enhance the potential of any and cut of 16 db at 30 Radio Corporntion, 37 -04 36th spectively. All controls are of the dual -ganged jects low- frequency noise. Treble control pro- system. Pilot simulta- vides 13 db boost and 18 db attenuation at St., Long Island City 1. N. Y. User net price, type, operative on both channels with enclosure, $199.50. neously. Distortion is less than 0.1 per cent 20,000 cps; bass control provides 16 db boost complete for 1.25 -volt output. A balance control allows and 20 db attenuation at 20 cps. Fletcher- 240 30w ster preamp -ampi $129.50 for a great difference in sensitivity between Munson -type "aural compensation" control is 245 -A 40w ster preamp -ampi 199.50 speakers. This new unit has been expressly continuously variable. The C -20 matches its 232 40w basic ster ampi 89.50 British impressive performance with handsome ap- 260 70w basic ster ampi 139.50 matched to all Leak power amplifiers. 89.50 Industries Corporation, 80 Shore Rond. Port pearance. McIntosh Laboratory, Inc., 4 SP2I0 ster preamp Washington, N. Y. User net price, less cabinet, Chambers St.. Binghamton, N.Y. User net $109.50. price, $225.00. Ster 50 ster ampi $189.00 MC -30 30 w amplifier $143.30 PRECISE Ster 20 ster ampi 149.00 MC -60 60 w amplifier 198.50 Stereo Amplifier-Preamplifier. Containing two individual amplifiers and preamplifiers on MARANTZ PACO a single compact chassis, the Integra Mark XXIV affords stereo users two audio channels. Stereo Console. The Mnrantz Model 7 is a Sterco Preaunp-Amplifier Kit. The Paco each with a continuous power rating of 20 preamplifier- control unit Model SA -40 consists of two 20 -watt ampli- When desired the two channels may be self -powered stereo control watts. which features n high order of versatility. fiers. each with its own preamplifier- combined for monophonic operation with a together with remarkable ease of operation. system. on a single chassis. It is mounted 40 -watt power rating. Although low in Cost, It will deliver unexcelled performance when in an attractive gold and satin black case. the Integra offers many features of higher - stereo or monophonic pro- with satin gold panel to blend harmoniously priced amplifiers. Frequency response Is used with either a true gram sources. Typical of the quality inherent with all decors. The amplifiers deliver stated by the manufacturer to be fiat from 18 Especially 20 watts output per channel due largely to with harmonic distortion and in this unit is the volume control. supply. to 20,000 cps, developed for Mnrnntz. each control is in- a well -regulated low -impedance power interntodulation less than 0.4 per cent and for 2 -db tracking at any There is no clipping even on sustained high - 0.6 per cent, respectively, at normal listening dividually tested a mini- point of rotation down to 65 db attenuation: level passages. Distortion is kept to levels. Separate boss, treble, and volume con- step -type feed- mum because of the unique main feedback are supplied for each channel. A master total range is 90 db. Separate com- trols back tone controls with identical curves are circuit which eliminates phase-shifting

ponents. In addition to all the standard con- trols and switches the Model SA -40 includes: two dual phono inputs to permit the use of loudness operates on both channels simul- both record changer and manual turntable, taneously. A three -position contour switch special switching which affords selection of permits adjustment to room acoustics. Chan- additional speaker systems anywhere in the nel reversal is accomplished by means of a is channel. The steps are home, and Balance -Right and Balance -Left panel -mounted slide switch. The Integra incorporated in each on a white and gold 3.0 db at 50 cps and 21/2 db test selector for a simplified aural check handsomely finished with in increments of the balance of Iwo speakers for best stereo contrasting front panel. Precise Development nt 10.000 cps; both controls are removed N.Y. A full -range results. Frequency response measured at 1.0 Corporation, 2 Neil Court, Oceanside, from the circuit in flat position. to 90,000 cps balance control permits complete cut -off of watt steady -state output is 30 User net price, $99.95. response is 20 to + LO db. Intermodulation and harmonic dis- either speaker. Frequency than 1.0 per cent and 0.2 20,000 cps ± 0.5 db. Intermodulation and tortion are less are reduced to negligibil- per cent, respectively, nt full rated output. harmonic distortion The -40 is supplied with step -by -step as- SARGENT -RAYM ENT ity. Hum is far below thermal noise. Nine SA three pairs of outputs are senility instructions and giant -size wiring Stereo l'rcatnplificr- Aoepliler. Developed for pairs of inputs and ensure easy and successful as- mounted on rear panel. The Model 7, while diagrams to use in advanced music systems, the S-R offers a measure of perform- sembly. PACO Electronics Company, Inc., Model 1717 meets professional standards not inexpensive, -31 St., Glendale 27, N. Y. User net ance well in keeping with its price. Maranta 70 84th throughout. It is a combination on a single price, in kit form, $79.95 ; factory wired, Company. 25 -14 Broadway, Long Island City chassis of two preamplifiers, including tone 6, N. Y. User net price, less cabinet, $249.00; $129.95. controls, with a stereo power amplifier, each cabinet, in mahogany, walnut or blond, $24.00. channel of which is rated at 20 watts. All PILOT ganged type, affording $153.00 controls are of the dual 1 mono Audio Consolette A stereo 219.00 Introduced by ease and accuracy of stereo tuning. 2 40w pwr ampi Stereo Preamplifier -Control. balance control provides equal volume from 5 30w pwr ampi as being "as professional as a stereo- 4U 00 Pilot both channels at any point in the listening eiec x -over phonic preamplifier can be," the Model 216 -A are used in a high- facility which could be room. Type 7189 tubes offers virtually every efficiency push -pull output circuit, delivering desired for comprehensive audio control. Two and McINTOSH for In- less than 1.5 per cent Intermodulation illuminated VU meters incorporated less than 0.5 per cent harmonic distortion at Sterco Preamplifier -Control. Designated as rated output. Bass and treble controls afford Model C-20 Stereo Compensator, this new boost at 40 and 10,000 cps, the for the up to 15 db McIntosh development is designed respectively, with less than 1.0 db rise at mid - music lover who insists on the nearest possible frequency. Carbon -deposited resistors are approach to perfection. Full stereo flexibility used in the preamp for minimum noise. Fre- is provided plus bult -in protection for the quency response is within ± 1.0 db from 20 to user's investment in monophonic records. -Fre- 15,000 cps through the entire system with quency response is 20 to 20,000 cps + 0.5"db. tone controls set flat. A separate audio out- Distortion is under 0.2 per cent at rated out- put is supplied from each channel for tape High - put over the entire frequency range. recording. An 8- position selector switch con- level-input hum and noise level is 85 db below rated output of 2.5 volts. Six -position mode selector includes: stereo; stereo reverse; left ; right channel on channel on left speaker only dicating tape recording output level, or for visually balancing the channels of a stereo- 1.11111111M phonic music system. Exclusive Trolok tone controls permit treble and bass adjustment for each channel separately, or ganging for simultaneous adjustment. Fourteen inputs in- clude two each for phono record changer, phono turntable, tape head, microphone, FM- AM, multiplex, tape recorder. Loudness con- tour control applies Fletcher- Munson com- pensation to both channels simultaneously. Electronic crostover feeds low frequencies to AUDIO AUGUST, 1959 70 trola inputs and equalization for various matched by its flexibility of operation, con- 4300 N. California Ave., Chicago 18, 111. User types of recordings. Sargent -Rayment Com- taining, as it does, control for most every net price, less case, $189.50. pany, 4926 E. 12th St.. Oakland 1, Calif. conceivable stereo or monophonic function. User net price, including attractive metal Il. H. Scott, Inc., 111 Powder Mill Rond, 5 -1060 60w comp ampi $149.50 housing, $189.60. Maynard, Mass. User price, $199.95. S- 100011 36w comp ampi 109.50 net S -4400 36w add -on basic ampi, ster SR -570 70w basic ampi 119.50 99D 22w comp amp! $109.95 preamp 159.50 SR2000 ster preamp 163.50 222 24w comp ster ampi 139.95 SR -5100 100w ster basic ampi 183.60 250 40w pwr ampi 119.95 130 Ster preamp 169.95 STROMBERG-CARLSON H. H. SCOTT 135 Stereo - Daptor 24.95 Stereo Control Amplifier. The Stromberg- Carlson Model ASR -433 is n completely versa- Stereo Amplifier. The Scott Model 299 is a SHERWOOD tile antpli''er which can be used for stereo or complete stereo amplifier- control center. It monophonic reproduction, or as an electronic is conservatively rated at 40 watts and in- Stereo Amplifier -Preamplifier. The new crossover for monophonic operation with a cludes two complete channels with dual pre- Sherwood Model S -5000 incorporates two tweeter and woofer. Each of its two chan- amplifiers and dual 20 watt power sections. channels with a continuous power handling capacity of 20 watts each. It permits either 20- watt -stereo, or 40- watt-monophonic oper- ation with only one set of basic coordinated controls, yet offers every important control feature essential to both stereo and mono- phonic operation. These include 10 two - channel controls, stereo normal/reverse III switch, phase inversion switch, and dual am- plifier monophonic operation with either set of input sources. All controls normally oper- ate both channels simultaneously. In addition, the - bass and treble controls feature friction nels has a continuous power rating of 12 locked shafts which allow the adjustment of watts with frequency range of 20 to 20,000 Among its advanced stereophonic features is each channel separately when desired. Also ± provided cps within 1.0 db. Intermodulation and a third -channel output for eliminating the is operation of a stereo phono car- harmonic distortion are both under 1.0 per "hole -in- the -middle" effect. Separate bass and tridge playing n monophonic record with cent. The exclusive Stromberg- Carlson "out- treble controls are provided for each channel vertical rumble and noise components bal- anced put balance signal" permits balancing of the to permit compensation for differences in out. Frequency response of the S-5000 two channels by a signal tone. Each channel speaker characteristics. Low -level stereo car- has its own set of controls- loudness /volume, tridge inputs have 3.0-mv sensitivity for ac- bass and treble -plus a master gain control commodation of pickups with very low out- which affects both channels simultaneously. put. Phase -reversal switch corrects for re- Full -frequency feedback provides minimum versed phasing on improperly made tapes and distortion at all frequency levels. D.c. is recordings. In addition to its function as a superimposed on all preamp filaments, bring- stereo amplifier, the 299 can also be used as ing hurls and noise level down 63 db. Match- an electronic crossover. Special balancing ing impressive performance with distinctive circuit permits quick and accurate channel appearance, Stromberg- Carlson amplifiers are balance. Preamplifier tubes have d.c. on fila- designed by Joseph Federico, one of the coun- ments to minimize hum. Frequency response is 20 to 20,000 cps within ± 0.5 db. Harmonic try's leading designers. Stromberg- Carlson, of the 299 is stated by the manufacturer to distortion and intermodulation are 0.5 and 1.5 Special Products Division, 1400 N. Goodman be virtually flat from 20 to 30,000 cps. Inter - per cent, respectively, at full rated output. St., Rochester 3, N.Y. User net price, $129.95. modulation and harmonic distortion are less Styling and front -panel size are identical than 0.3 per cent and 0.8 per cent, respec- with that of other Sherwood amplifiers and ASR -333 24w ster ampi $ 99.95 tively. Hum is stnted to he 80 ASR -444 60w ster ampi 169.95 db below rated the S-2000 FM -AM tuner (see Tuners on page ASR -434 ster preamp 99.95 output. Technical excellence of the 299 is 74). Sherwood Electronics Laboratories, Inc., ASR-422 40w ster pwr ampi 99.95

TUNERS

ARKAY Van Wyck Expressway. Jamaica 18, N.Y. User net price, $49.95 ; fully wired, $74.50. Stereo -Binaural Taner Kit. The Arkay AM -5 AM tuner $ 29.95 ALTEC Model ST -11 is designed for simultaneous FM -6a FM tuner 25.75 reception of FM and AM broadcasts, or for HFT -7 FM -AM tuner 32.00 AM-FM Tuner. Employing a fully shielded monophonic reception of either. In effect it FM -8 FM tuner 39.95 extra large tuning capacitor directly mounted is two distinct self -powered tuners mounted to the chassis for perfect grounding, the care- on a single chassis. Sensitivity on FM is 4.0 BELL fully designed circuit layout and complete microvolts for 20 -db quieting. Three wide - isolation between transformers and power band high -gain i.f. stages and Foster- Seeley AM-FM Stereo Tuner. One of the newest ad- mains in the 300A tuner reduce coupling to a discriminator assure excellent selectivity. ditions to the Bell line is the Model 3070 AM- point that easily exceeds FCC radiation re- Image rejection is 30 db minimum. FM fre- FM stereo tuner which matches in styling the quency is 20 quirements. The FM section employs a Foster - response to 20,000 cps within stereo amplifier of the sane company. This Seeley discriminator. "cascode" low -noise ri. 0.5 db, with distortion less than 1.0 per cent. unit features automatic frequency control, stage, triode low -noise mixer, n.f.c., and two Variable n.f.c. adds to flexibility of FM tun- logging scale. multiplex output, and a stereo limiters. AM section lies three 1.f. trans- ing. Hum level is down 05 db. AM section selector switch which feeds either AM or FM monophonic signal through both channels of the stereo amplifier. or feeds both simultane- ously to separate channels for stereo. FM

ecii,i Iia> a ,rm1Init ,d r; mir r olis for 20 db of aiuict ing, and image rejection is 28 db. Hum and noise are 50 db below 100 per cent formers for flat pass bond, and sensitivity features variable -bandwidth 1.f. stages, with modulator. The AM section furnishes a 0.1- is frequency volt output signal from a 20- microvolt 3 microvolts on an outside antenna and 50 response of 20 to 8500 cps in broad- input microvolts with band position. Image rejection is 30 db mini- signal. while both channels give a 2.5-volt out- the built -in Ferrite loopstick. put at 100 per cent modulation Distortion is less than 1.5 per cent at 30 mum. A 10 -kc. whistle filter eliminates inter - at usual input Per station interference. signal levels. Cabinet has unusually low sil- cent modulation on AM and less 1 Features common to both than per houette, only 43¢ in. cent at 100 per cent modulation on FM. sections are adjustable grin control, flywheel being high by 16 in. wide tuning, and edge -lighted and 11% in, deep. Bell Sound Division, Thomp- Cathode follower output. Altec Division, Ling - 0-100 logging scale. Altec, 1515 S. Manchester Ave., Anaheim, The advanced engineering features contained son Ramo Wooldridge Inc., 555 Marion Rd., California. User net price, less cabinet, $199.50. in the ST -11 provide the custom builder a Columbus 7. Ohio. User net price, $139.95. stereo tuner of excellent sensitivity and flexi- 307A FM tuner $96.00 2216 "Pacemaker" FM tar $ 69.95 bility of operation. Radio Kits, Inc., 88-06 2222 " AM -FM ster tnr 109.95

AUDIO AUGUST, 1959 71 distant stations. A high Q filter eliminates 200 microvolts /meter provide a 20 -db signal- BOGEN- PRESTO 10-kc whistle while reducing response by no to -noise ratio. FM frequency response falls -wave within + 2 db of fiat from 20 to 15,000 cps, Receiver. The Bogen- more than 3.0 db at 9000 cps. A full Budget-Priced Sterco 25 db at 10 ke for Model RC412 is an rectifier and heavy filtering provides n stable while AM response is down Presto "Challenger" suppression. Tuning meter indi- FM -AM stereophonic receiver with a dual hum-free supply. R.f. and i.f. coils are supplied interference so cates center- channel tuning on FM and peak 6- watts -per -channel amplifier which delivers pre -aligned that no test instruments are monophonic operation. Frequency needed for satisfactory operation of the com- of AM signal, and there is no audible drift. 12 watts in employs r.f. amplifier stage in both response is 30 to 15,000 cps. Inputs are pro- pleted kit. Additional features Include slide - Circuit and for increased sensitivity vided for magnetic and crystal phonograph rule dial. flywheen tuning, auxiliary output AM FM channels for recording. and front -panel volume control. and reduced noise. General Electric Company, Image rejection is 58 db. Precision tuning is Specialty Electronic Components Departtnent, achieved by a traveling eye indicator which Utica, New York. User net price, $129.95. contracts into an "exclamation point" at the exact center of each broadcast channel. The HFT94 is also available completely wired, GROM M ES ready for installation. Electronic Instrument Co., Inc., 33 -00 Northern Blvd., Long Island FM-AM Sterco Tuner. Matching the new 1, N. Y. User net price, $39.95; fully Grommet; "Premiere" series of amplifiers in City tuner wired, $65.95. appearance, the new Model 103GT stereo features FM sensitivity of better than LO HFT -90 FM tuner .. kit, $39.95; wired $65.95 -db quieting. The FM section HFT -92 AM -FM tuner kit, $59.95; wired, microvolt for 20 $94.95 has grounded -grid input, tuned cascode r.f. cartridges, tape recorder, and auxiliary equip- FISHER ment. The receiver has built -in antennas for foth FM and AM, as well as a connection for Super- Sensitive FM Tuner. Introduced by outside antenna. A multiplex switch Is also the manufacturer as the most sensitive FM provided. Hum and noise level is down 58 db tuner In the world, the Fisher FM -100 re- on FM, 48 db on AM, and 45 db on all other quires only 0.4 microvolt for 20 db quieting inputs. Distortion is 1.5 per cent on FM, 3.0 with a 72 -ohm antenna. Frequency response per cent on AM, and less than 1.0 per cent Is 20 to 20,000 cps ± 0.5 db, with a 60-db ou phono and tape channels. Audio sensitivity signal -to -noise ratio for 100- microvolt input, is 4.0 my for magnetic cartridge and tape and distortion is less than 0.5 per cent at full operation. Dimensions are 16'F- "w x 12% "d x modulation. The wide -band ratio detector, 51/2 "h. Bogen -Presto Company, a Division of Paramus, N. J. User The Siegler Corporation, control. dual limi- net price, less enclosure, $169.50; enclosure, stage, automatic frequency ters, and broad -band Foster -Seeley discrimi- $8.50. nator. Matched crystal diodes are used for FM51 Basic FM tuner $115.00 detector. The AM section has variable i.f. T661 Basic AM -FM tuner 139.50 selectivity, infinite- impedance detector, and ST662 AM -FM Stereo tuner 189.50 10 -kc whistle filter. FM frequency response is 20 to 20,000 cps ±0.5 db ; AM response is 20 to 7500 cps ±3.0 db in broad -band position. DE WALD Tuning meter, flywheel tuning, and slide -rule Sterco Tuner. Modest price and good per- scale simplify station selection. Output is pro- formance are combined in the De Wald Model vided for FM multiplex. FM distortion is re- N- 1000 -B "Ambassador" FM -AM stereo tuner. duced to negligibility at 100 per cent modula- Included in the circuitry are eight tubes plus tion. Push-button switches control tuning diode detector and rectifier, with four stages meter, AM bandwidth, a.f.c. input, and power of i.f., including discriminator. Sensitivity is off-on. Precision Electronics, Inc., 9101 King using a matched pair of germanium diodes, St., Franklin Park, Ill. User net price. $201.95. offers completely linear and distortion -free operation entirely free of hum. Instantaneous - acting dual dynamic limiter stages are highly HARMAN -KARDON effective on any signal. whether strong or weak, eliminating ignition interference and FM -AM Stereo Tuner. Engineered as a com- other noise elements. A Multiplex Separation panion piece to the H -K "Ballad" Model A230 control is included on the front panel, plus stereo amplifier. the "Sonnet" Model T230 Main and MPX channel positions on the se- tuner incorporates separate AM and FM sec- lector switch. while power and electrical tions for receiving stereo broadcasts. A jack connections and apace bave been provided for in the rear makes it readily adaptable for simple plug-in installation of the Fisher multiplex reception. The Sonnet employs a MPX-20 multiplex adaptor when desired. The new low -noise front end consisting of 3M microvolts for 20 -db quieting. Frequency i.f. stages are flat- topped, with an unusually grounded -grid cathode -fed r.f. amplifier, response is 20 to 20,000 cps and hum level is wide band for maximum fidelity and mini- double-tuned overcoupled r.f. interstage, and stated as being 70 db below 1.0 volt. Response mum distortion, plus steep skirts to eliminate low -noise grid -fed triode mixer, followed by of a.f.c. is +0.8 megacycles at 100 microvolts. adjacent- and second -channel interference. Output jacks include AM, AM -FM monophonic, Included in the circuitry of the FM -100 are FM stereo, AM tape. FM tape, and multiplex. a dual- triode mixer-oscillator, the Fisher The tuner is cased in an attractive black Micrognp cascode r.f. stage, four wide -band picture-frame housing with brushed -brass face Lt. stages, and a wide -band ratio detector. plate. De Wald Radio Division of United Four controls on the FM -100 include Tuning, Scientific Laboratories, Inc., 35 -15 37th Ave., Selector Switch, Muting Control, and Multi- Long Island City 1. N.Y. User net price, in- plex Separation. Fisher Radio Corporation, cluding cabinet, $99.95. 21 -21 44th Drive, Long Island City 1, N.Y. User net price, less cabinet, $159.50. 600 AM -FM ster tnr, preamp, and EICO 20w ampl $349.50 transitionally- coupled i.f. stages. It uses an Wide-Range AM Tuner Kit. The new Model Armstrong circuit with pentode limiter, wide - HFT94 is a basic AM tuner designed primarily and auto- matches GENERAL ELECTRIC band Foster -Seeley discriminator, for high fidelity application. It in matic frequency control. The AM circuit is a and appearance EICO HFT90 FM a new unit size the AM -FM Tuner. Model FA -11 is superheterodyne with a.v.c. and a built -in tuner. the two tuners making excellent com- which features high sensitivity, precision tun- ferrite loopstick antenna. FM sensitivity is panion units for stereo operation. The HFT94 ing. and an unusually low hunt and noise level. 3.5 microvolts for 20 db quieting; 7.0 micro- cps offers a choice of wide bandpass to 14.000 It is equipped with an FM multiplex jack for volts for 30 db quieting. FM frequency re- bandbass when for high fidelity operation, or narrow reception of multiplexed programs used sponse is 30 to 15,000 cps ± 0.75 db. Inter- is to receive to 7000 cps when the objective with an adapter. FM sensitivity is 5.0 micro- modulation is under 3.0 per cent at 100 per volts for 30 db quieting. and AM signals of cent modulation. Harman-Kardon, Inc., 520 Main St., Westbury, N.Y. User net price, with enclosure, $114.95. T224 "Duet" AM -FM ster tnr $114.95 TA230 "Festival" AM -FM ster tnr, pre - amp -ampi 259.95

HEATHKIT FM -AM Stereo Tuner Kit. Outstanding fea- tures in both circuitry and styling in the PT-1, a 16-tube deluxe FM -AM combination, include:

AUGUST, 1959 72 AUDIO can he used simultaneously for FM -AM stereo broadcasts. A cathode -follower multiplex out- put is provided for use when this form of transmission becomes available in the listen- er's locality. An exclusive dynamic- sideband- regulation circuit controls incoming signal to reduce distortion of very weak or over -mod- ulated signals on FM. FM sensitivity is 2.5 microvolts for 20 -db quieting ; 4.0 microvolts for 30 -db quieting. Circuit includes limiter - detector with dual limiters, tuned r.f. ampli- fier, and switched automatic frequency con- trol. FM frequency response is 20 to 20,000 three circuit boards for easy construction and cps ± 0.5 db. AM sensitivity is 5.0 microvolts PI LOT high stability ; wired, prealigned 3 -tube FM for 20 db signal -to -noise ratio. and frequency Stereo FM -AM Tuner. The Pilot Model 680 tuning unit ; tuning meter ; a.f.c. with on -off response is essentially fiat from 50 to 7000 switch, and flywheel cps. Three -position variable- bandwidth is a deluxe unit built to professional specifi- tuning. FM and AM i.f. is cations, circuits are separate and employed in the AM section. A separate and which offers unsurpassed recep- individually tuned. tion, even In Cathode -follower outputs with cathode -ray tuning indicator is incorporated difficult fringe areas. Its inde- individual pendent AM and FM level controls are provided for both sections. for each tuner. Handsome in appearance, the sections may be used Other features include variable KN -125 will lend distinction to individually for monophonic reception, or AM band- any surround- simultaneously width. 10-kc whistle filter, tuned -cascode ings. Allied Radio Corporation, 100 N. West- for stereo broadcasts. With an FM external multiplex demodulator 680 front end, FM ern Ave., 111. the will n.g.c. and amplified a.v.c. for Chicago 80, User net price, provide FM- AM. Unique i.f. limiter design automatically $139.95. multiplex reception. The FM provides tuner section features 1- microvolt sensitivity the number of limiting and l.f. for stages required for non -flutter reception of LEAK 20 -db quieting. Freedom from drift is assured by means of a temperature- compen- weak or strong stations. Depending on signal FM Tuner. strength anywhere from The new "Trough Line II" tuner sated oscillator. Wide -hand detector (1000 kc one to four limiters matches in appearance the newly -styled wide) makes or i.f.'s are automatically. provided. FM Leak tuning non- critical. Interstation "Point One" stereo preamplifier. noise suppression (muting) is equipped sensitivity is 2.0 microvolts for 20 -db Sensitivity with quiet- of L5 microvolts for 20 -db quieting makes control for defeat when ing. Harmonic distortion is less than 1.0 per desired. Audio output practical the reception of FM stations on Is constant and independent cent. Frequency response is 20 to 20,000 cps of signal level. ±2 db on FM. A jack The AM section of the 680 has sensitivity of is provided for use of n 2.0 microvolts multiplex converter without changing /meter. It employs a germanium exist- diode detector for lowest possible distortion. ing circuitry. The tuner is housed in a vinyl - Featured is a high -gain pentode clad steel cabinet finished in black with gold r.f. amplifier, trim. Heath two steep -skirted i.f. stages with front -panel Company, Benton Harbor, Mich. band User net price, $89.95. -width control, and a 10 -kc whistle filter. A rejection trap is incorporated for i.f. inter- BC -1A AM tuner $ 26.95 ference. Separate precision tuning meters are provided for FM and AM. Built -in ferrite core antenna. Dual cathode followers permit long KARG output cables without signal loss. The 680 is an impressive 7'weive- Channel FM Tuner. Although simi- instrument in all respects. Pilot lar basically Radio Corporation, 37-06 36th St., Long to earlier versions of the Tune- Island matic FM tuner, the new XT series City 1. N.Y. User net price, complete embodies with enclosure, $219.50. a number of notable improvements. Up to 12 channels may be had in the new models, each 690-A AM -FM ster tun, stet preamp .. $289.50 considerable channel individually controlled by a precise distances. Cathode- follower out- 590 AM -FM ster tun, ster preamp .. 239.50 quartz crystal ground to military specifica- put delivers 1.0 volt and facilitates the use of tions. In effect, the Tunematic is a group of long output leads with negligible high fre- PRECISE fixed -frequency quency attenuation. Automatic frequency tuners mounted on a single FM-AM Tuner. Despite chassis. Other refinements in control is included in the circuitry for drift - its low cost, the the newly -de- "Perfecta" is a tuner of distinctive appear- signed chassis include a volume control com- free tuning. A magic eye assures tuning accuracy. Controls include on-off switch. a.f.c. ance and excellent performance. Among its off -on, tuning, and local -distance. Chassis features is a tuning meter which assures ac- curacy of dimensions are 10t,ß "w x 7% "d x 33/4 "h. station selection. Circuitry includes British Industries Corporation. 80 Shore Road, Port Washington, N.Y. User net price, less cabinet, $129.00. McINTOSH FM -AM Tenter. Developed for the connois- seur, the MR -55A tuner sets high standards in distortion -free FM -AM reception. The FM section has a sensitivity of 3.0 microvolts at 100 per cent modulation for less than 3.0 per bined with power switch on the front panel, cent total distortion, using IHFM measure- and the use of silicon diodes to replace the ment standards. Distortion -free a.f.c. is com- a power tube rectifier with the accompanying advan- pletely variable. Hum is 70 db below full sig- transformer. with full -wave rectifica- tages of cooler operation and indefinite life. nal. Capture ratio is 1.0 to 0.8. Frequency tion. Output is of the cathode- follower type. re- Included Frequency response of the XT series is stated sponse is 20 to 20.000 cps +3.0 db. I.f, band- in the circuit are two limiters, a to be 15 to 30.000 cps ± 0.5 db from antenna width is 200 kc, flat on top. Silence between Foster -Seeley discriminator, and a three -gang to capacitor. cathode -follower output. Intermodulntion stations while tuning is achieved by means of tuning A logging scale and flywheel Is 0.5 per cent maximum at 100 per cent tuning assure precision tuning on both FM modulation- The dial of each Tunematic is and AM. Panel- mounted function switch af- custom tailored for the area in which it is to fords selection of phono. FM, Alf, or TV. be used. If the user moves, crystals can be Variable a.f.c. eliminates drift effect on FM. exchanged to cover his new location at no Precise Development Corporation, 2 Neil extra cost. Karg Laboratories. Inc., South Court. Oceanside, N. Y. User net price, less Norwalk, Conn. User net price, including cng^. $99.95. ventilated metal cabinet, $199.50. SARGENT-RAYMENT KNIGHT Stereo FM -AM Tuner. Strictly deluxe in every- respect, the SR -1000 offers every feature FM -AM Stereo Tuner. The Knight Model which could be desired in an instrument of KN -125 incorporates two sensitive tuners on this type. Sensitivity of 0.85 microvolts for a single compact chassis. The tuners can be 20 -db quieting on FM is achieved by means of used individually for AM or FM reception, or McIntosh "Ultrasonic" muting circuit. AM section features 3- position i.f. bandwidth con- trol, with frequency ranges to 9500, 6500, and 2000 cps. Exceptionally strong a.v.c. assures less than 4.0 db audio output change with variation in input from 10 to 100,000 micro- volts. Sensitivity selector has three positions. 1Vhistle filter has 70 -db rejecton at 10,000 cps. Two tuning meters are incorporated in the MR -55A, one each for FM and AM. McIntosh Laboratory, Inc., 4 Chambers St., Bingham- ton, N.Y. User net price, $225.00.

AUDIO AUGUST, 1959 73 advanced circuitry and use of a gold -plated response from cross modulation by strong station whistle while reducing audio response frame -grid cascode tube. Minimum AM dis- local signals makes possible the use of this less than 3 db at 8 kc. A built -in ferrite -rod tortion is assured through use of the well- tuner in any location, even close to FM trans- antenna is pivot- mounted and may be oriented known S -R 2 -tube detector system. Two inde- mitters. The AM section of the 330 -D con- for best reception of distant stations. FM pendently operated tuning indicators are tains n 3- position adjustable i1. bandwidth- frequency response is 20 to 20,000 cps within incorporated. FM frequency response is 18 to wide- range, normal, and distant. A 10 -kc ± 0.5 db. A multiplex output jack is provided 22,000 cps ± 1.0 db. Distortion is less than whistle filter minimizes interstation inter- for connection to a multiplex adapter. Sher- 0.5 per cent at 100 per cent modulation. Drift ference. Low -impedance outputs permit in- wood Electronics Laboratories, Inc., 4300 N. is negligible after 10 -sec. warmup period. The stallation of the tuner at any practical dis- California Ave., Chicago 18, III. User net S -R loopstick, said to be the largest produced tance from the amplifier without signal de- price, less case, $145.50. are incorporated commercially, assures optimum AM signal -to- terioration. Separate outputs 5- 300011 FM tnr 105.50 noise ratio. Variable band -width i.f. permits for tape recorder and for multiplex. Notwith- wide-range reception on AM, also excellent standing its compactness, the 330 -D is an selectivity for distant stations. Whistle filter excellent performer in every respect. H. H. STROMBERG-CARLSON gives 65 -db attenuation at 10 kc with no effect Scott, Inc., 111 Powder Mill Road, Maynard, $224.95. FM -AM 7'uncr. Engineered for easy, accu- at 8.5 kc. Cathode follower outputs are used Mass. User net price, rate tuning. the Stromberg- Carlson Model SR- AM FM. -Rayment Com- for both and Sargent 310C FM tuner $174.95 440 also features high sensitivity to provide pany, 4926 E. 12th St., Oakland 1, Calif. User 3110 FM tuner 124.95 outstanding FM perfortnnnce in fringe areas net price, $184.50. 320 AM -FM tuner 139.95 and to permit reception of distant AM sta- SR -380 AM -FM tun, ster preamp .... $199.20 tions. FM sensitivity is 0.9 microvolt for 20 -db quieting. Wide peak -to -peak separation (550 SHERWOOD kc), a long linear slope (350 kc) of the bal- H. H. SCOTT FM-AM Tuner. Featured in the Model S- anced -ratio FM detector, and low -noise 2000 II tuner is one of the most sensitive FM golden -grid cascode front end result in high FM -AM Stereo Tuner. The wide -range AM circuits ever developed, permitting 20 db signal, low noise, and exceptionally stable section of the Model 330 -D tuner, plus n highly quieting with only 0.95 microvolt signal in- output. Improved temperature- controlled cir- sensitive, drift -free, wide -band FM section put ; 3.6 tnicrovolts affords n signal -to -noise cuitry eliminates drift for all practical pur- make it an excellent choice for the reception ratio of 50 db. This unusual sensitivity makes poses. Frequency range on FM is 20 to 20,000 FM reception practical beyond 100 miles. In addition, highly stable coil design, delayed automatic gain control, and Foster- Seeley type discriminator preceded by three limiters, assure a minimum of distortion even with modulation over 100 per cent. The AM sec- tion of the S -2000 II features a selection of either a 15 -kc wide "hi -fl" bandpass or a sharply selective 5 -kc bandwidth for listening to weaker stations without noise and inter- ference. A high -Q filter traps out 10 -ke inter- un AM it is _o io 7000 in broad band - wid.h position. FM i.f. bandwidth is 20(1 kc; kc sharp. The tuner is of AM -FM stereophonic broadcasts. FM sensi- AM is 15 kc b "ond. 8 tivity is 1.0 microvolt for 20 -db quieting with well within FCC requirements for spurious matched 72 -ohm antenna. Illuminated tuning radiation. Distinctively styled with white for both FM and face plate and hu niched brass escutcheon and and signal -strength meter its impressive per- AM permits precision tuning of very weak knobs, the SR -440 matches stations. Automatic gain control affords low formance with hand'ome appearance. Special capture ratio, assuring rejection of inter- Products Division. Stromberg- Carlson, 1400 ference practically as strong as the station N. Goodman St., Rochester 3, N.P. User net price, $159.95. being received ; 80-db rejection of spurious LOUDSPEAKERS watts. Acoustic Research, Inc., 24 Thorndike are 111/4"h x 23 "w x 1134"d. User net price, ACOUSTIC RESEARCH St.. Cambridge 41, Mass. User net price, in in walnut. blond or mahogany, $79.50 ; unfin- mahogany or birch. $96.00 ; utility, unfinished ished, $69.50. Low -Cost "Acoustic- Suspension" Speaker $102.00; System. Selling for less than a hundred dol- pine, $89.00; walnut or cherry, 7003 "Melodist" system $126.00 lars, the AR -2 speaker system uses the AR- korina, $111.00. 830A "Laguna" corner spkr system 599.00 spkr system 399.00 patented acoustic- suspension principle, in AR -1 full -range spkr system, mah ... $185.00 832A "Ccrena" corner un- mah 145.00 833A "Verde" spkr system 309.00 which a small enclosure is accompanied by AR-1W woofer only, Duplex 15" loudspeaker 177.00 proved rather than compromised reproduction AR -3 full -range spkr system, mah 216.00 605A quality. In this design the speaker (woofer) cone is mounted on very free suspensions, so compliant that they are unable to provide the ALTEC AUDAX elastic restoring force normally required of Monterey Jr. Multi- Speaker Systems. Designed by George Economy Speaker System. The Nelson. one of the country's leading furniture is a compact moderately- priced system whose new Audax of some and industrial designers. the quality of reproduction equals that speaker series brings a distinctive blend of systems costing considerably more. A small beauty and functionalism to component high ruggedly -built bass reflex enclosure houses an speaker -excursion" fidelity. "The idea behind the Audax Altec 402A 8 -in. "controlled- linear systems was to make them interesting, excit- newly -designed 2000A direct - speaker and the ing furniture pieces. beautiful in appearance radiator cone tweeter. Frequency range of said Mr. Nelson. The by manufac- as well as sound." the Monterey Jr. is stated the Audax cabinets are finished on all four sides, turer to be 20 to 18,000 cps. and power rating is 15 watts. Impedance is 16 ohms. A single Monterey Jr. is excellent for monophonic listen;ng, while two make an ideal medium - pr'ced stereo system. It can be flush -mounted in a wall or ceiling, or used in a console as an integral part of a music system. Dimensions

them. The missing elasticity is then reintro- duced by the pneumatic spring formed by the air within the cabinet. The cone literally rides on air instead of on mechanical springs. The small enclosure size is necessary for optimum performance. The AR -2 is a 3- speaker system comprising a single woofer and two 5 -In. free Each Frequency response is more than to be used as wall units or standing. tweeters. model Ices detachable legs and a new type of adequate to cover the entire range of musical -dimensional "acoustical Horizontal dispersion is 90 deg. speaker grille, a three instruments. screen" which can be removed easily for Dimensions of the AR -2 system are 131 "h x two 8 -in. for use with cleaning. Model CA -80 contains 1156"d x 24 "l. Recommended speakers. Model CA -100 has amplifiers having power output of 20 to 40 extended -range AUDIO AUGUST, 1959 74 two 10 -in. woofers, plus two cone tweeters. three drivers to provide a measure of per- Both units are identical in external appear- formance which is hardly believable in a sys- ance. Both are intended for bookshelf place- tem of such compact size. The diffraction ment, and also may be used as floor units. horn employed on the tweeter makes the Both use Audax systems "Pernfiex" speakers, Esquire 200 ideal for use in pairs for full - a patented new design with many innova- range stereophonic reproduction. Supplied in tions, giving a sound quality which is smooth and natural. Audax, Inc.. Division of Rek -O- Kut Company, Inc., 38 -19 108th St.. Corona 68. N.Y. User net price for the CA-80 is $99.95; for the CA -100. $139.95.

AUDIO -TECH Wide -Range speaker System. Although ex- tremely compact. the Audio -Tech Model 1[íE12 has a frequency range of 37 to 20,000 cps.

BRADFORD Compact Wide -Range Speaker Enclosure. The Bradford enclosure. made in four sizes for 8 -, hand- rubbed hardwood veneers, it will add 10-, 12 -, and 15 -in. speakers, is only two inches distinction to even the most tasteful sur- larger titan the speaker it contains. Its con- roundings. Available in walnut, mahogany, struction is based on n variable- damping or limed oak. Electro- Voice, Inc., Buchanan, principle, in which speaker damping is varied Mich. User net price, $111.00. automatically by a pressure relief valve in the rear of the cabinet. Operation of the valve is coordinated with cone excursion. In reality, Thirty -Inch Woofer. This is the world's first it is an "acoustic spring" acting uniformly mass- produced 30 -in. loudspeaker. Engineered over the entire rear surface of the cone. expressly for use in the well -known E -V Boontiness and the effects of cabinet resonance "Patrician" 700, the Model 30W is also highly are virtually eliminated. The Bradford enclo- recommended for use in any custom instal- sure will enable the user to realize the poten- lation of exceptional quality. The speaker Containing a 12 -in. woofer and a 3 -in. cone - tial of most any speaker with which It is used. frame is a massive one -piece rigid casting type tweeter, it incorporates a special cali- Bradford Audio Corp., 27 E. 38th St., New which supports a true piston formation cone. brated level control for high -frequency bal- York 16. N.Y. Prices of the Bradford enclo- ance. Colored binding posts permit easy de- sure range from $39.50 to $69.50, depending termination of polarity for connection in on size and finish. stereo music systems. The speakers are fused 2 -126 Spkr system, mah $250.00 to prevent damage from accidental overload. 4 -12B Spkr system, mah Enclosures are made from selected walnut, 525.00 mahogany and fraitwood, with a handsome, hand -rubbed nil finish. Audio -Tech Labora- tories, 3420 Newkirk Ave., Brooklyn 3, N.Y. COSMOS' "AH!" User net price. $99.50. Electrostatic Mid -Range Speaker /Super Tweeter. Frequency range of the "eh !" ex- tends from 600 cps to well beyond the limits BOZAK of audibility. It mates easily and quickly with Small Speaker The any woofer or full -range speaker to provide System. Spinet, a new, extended high- frequency small speaker system has been introduced by response. Two push- Bozak to meet the needs of listeners who have a pronounced space problem. Measuring a compact 140,4 "b x 23',4 "w x 111/2"d, it has a

The cone in itself is revolutionary, being a one -piece molding of polystyrene foam manu- factured by a newly -developed injection -form- ing process. The 30W is capable of reproduc- ing boss tones in the range of 18 cps with earth -shaking reality. While tones pull capacitor these do elements give direct radiation not exist in pure form in commercially - over a full 120 -deg. arc. Polarizing voltage is recorded music, there are undertones and supplied by a built -in fused 1000-volt power sub -harmonics in this area which add dis- supply which consumes practically no current tinctly to realism in reproduction. Electra- and may be left permanently connected to a Voice. Inc., Buchanan, Mich. User net price, 117 -volt 60- cycle line. Crossover network is $139.00. self-contained. Recommended crossover fre- quency is 650 to 850 elm. The "ah !" may be paralleled across any conventional woofer FRAZIER without additional network. Two "all ! "s may 1w used in conjunction with n single woofer Compact Two-Way Speaker System. The for One Were., reproduction. Supplied in cabi- Monte Carlo. the newest and smallest Frazier net with hand -rubbed walnut finish. Other two-way speaker system. is made to order for finishes available on special order. Cosmos stereo. Measuring only 15%"w x 10%"h x Industries, 31 -28 Queens Blvd., Long Island 115ín "d, its size permits its use as n bookcase - naturalness of response in bass, mid -range City 1, N.Y. type speaker, and it is the most economical of and treble which is compatible with the larger all Frazier models for starting a stereo sya- Bozak speaker systems. The Spinet is avail- able in two models : the two -way B -500 sys- tem, and the three -way B -502 system. Both ELECTRO -VOICE models utilize the same finely- constructed, Ultra- Compact Spro her- System. Economy is integrated components found in larger Bozak preserved without any sacrifice of performance systems, and upon which the Bozak "Syste- or appearance in the E -V "Esquire" Model matic Growth" idea is based. This latter en- 200. The latest addition to the broad E -V line ables users to start with a modest installa- of ultra- compact systems. it is a full 3 -way tion. and then to "build" on it as they desire, system using specially designed and coordi- without having to replace initial components. nated components. Bass is delivered from a The Spinet is available finished in mahogany, highly-compliant 12 -1n. woofer with a long - blond, walnut. or ebony, or unfinished for throw voice coil. An S -in. cone driver is in- those who wish to match the cabinet to an corporated for smooth mid- range, and the existing decor. R. T. Bozak Sales Company, E -V Sonophase -throat -design tweeter handles Darien, Conn. User net price B -500, $134.50; the very highs. The acoustically- correct en- B -502. $209.50. closure is coordinated in design with the

AUDIO AUGUST, 1959 75 tem. It employa a modified Helmholtz -radiator members are heavy castings. Manufactured in JANSZEN principle, and has a frequency range from England. Goodmans speakers are distributed below 70 to 15,000 cps. Power handling ca- in the United States by Rockbar Corporation. Wide -Range Speaker System. The Z -400, pacity is 12 watts continuous. Tweeters are Mamaroneck, N.Y. User net price, Model 575 an inexpensive wide -range speaker system, mounted for right and left placement for with 50 -watt power handling capacity, marks the first time that the well -known stereo. The cabinet is equipped with two $232.50; Model 355, saune but with 40 -watt .iansZen electrostatic tweeter has been avail- concealed plastic feet and is finished in hand - power handling capacity. $196.50. able in a compact, shelf -mounted enclosure. rubbed natural walnut. The Monte Carlo is In the Z -400 the JansZen is acoustically 615 15" 3 -way spkr $147.00 shipped two to the carton, matched for stereo. 755 15" woofer 78.00 paired with the Model 350 11 -in. dynamic International Electronics Corporation. 2649 H750 "Midax" mid -range driver 58.50 woofer. The high -compliance cone of the 350 Brenner Drive, Dallas 20. Tex. User net is specially treated to provide low- frequency price, the pair, $99.50. reproduction which perfectly complements the JansZen tweeter. The Z -400 is stated to cover Cortez 2 -way spkr sys $125.00 HARTLEY 59.50 the range from 30 to beyond 30.000 cps with Scotsman 2 -way spkr sys Compact Full -Range Speaker System. The low Del Mar 2 spkr sys 79.50 exceptional uniformity and distortion. Hartley "Capri" comprises a full -range full - Tweeter and woofer are integrally mounted size speaker mounted in a handsome natural in a totally- enclosed Fibreglas -filled enclosure wood cabinet which measures 24 "w x 131/2"h x which may be placed vertically or horizontally GENERAL ELECTRIC 12 "d. The grill is made of bamboo, adding a as desired. A built -in power supply and high - power for the two push - G -E Two -Way Speaker System. Engineered pass filter furnish for high -quality sound reproduction in a lim- pull electrostatic elements, and eliminate the ited space, the Model G -501 is a new, com-

note of distinction to the appearance. The driver has n "polymerized" cone developed by Hartley engineers for rigidity and extreme lightness. Audible response extends from 30 to beyond 16.000 cps. The Capri cabinet is pact speaker system announced only recently filled with 35 linear feet of absorbent ma- by General Electric's audio components sec- terial to form in effect a "tunnel" 10 feet tion. Termed a "stereo- compact" system, the long. Hartley Products Company. Inc.. 521 E. G -501 will deliver excellent audio perform- 162nd St., New York 51, N.Y. User net price, ance, yet is only 22 "w x 13 "h x 9 "d, true $120.00. bookshelf dimensions. The new unit is based 217 full -range spkr $ 72.50 need for external crossover networks and on GE's extended -bass design, and has a 217 -Duo enclosure 146.00 attenuators. The Z -400 measures 15 "h X woofer, tweeter, and electrical crossover net- 26 "w x 13tf "d, and is available in walnut, work all housed in a dramatically styled en- mahogany and birch finishes. Neshaminy closure. The G -501 presents a departure from Electronic Corporation, Neshaminy, Pa. User previous G -E speaker systems, blending rich ISOPHON net price, $134.50. wood finishes, new grill patterns, and greater use of metal trini. User net price, $85.00. Three -Channel Four- Speaker System. Made in Western Germany by a foremost manufac- turer of speakers and speaker systems, the JENSEN Isophon III is a superb instrument utilizing GOODMANS a woofer. a mid -range compression type driver, "Satellite" Stem-co Speaker System. The new Jensen "Galaxy II" speaker system achieves Four -Way Speaker System. Built to a stand- and two tweeters. Matched through a uni- versal transformer and special divider net- wide panoramic stereo sound with two tiny ard of high quality without compromise, the satellites and a single small bookshelf -size new Goodmans "Tetraxiom" is a unitized 4- work, this combination assures utmost com- all intensity unit. The latter, which is called the "bass way speaker featuring the "Rigidflex" cone, pensation and tonal balance at center" speaker, may be placed on floor or a flexible free -floating cone rim and rigid levels and uniformity of response over the shelf wherever convenience and decor dictate. cone center to provide pure piston action. frequency range of 30 to 17,000 cps. The Finish on all four sides allows vertical or The Tetraxioms have high power capacity horizontal positioning. The Jensen "Flexair" and smooth response from 20 to 20,000 cps. high -compliance woofer has unusually low with usable response to 35,000 cps, according resonance and is capable of total motion of to the manufacturer. They are composed of sÿ in.. providing clean bass as low as 3G cps. four independent, concentrically- placed radi- The small satellite units handle midrange and ators, each of which is designed for maximum high frequencies. Their placement is not criti- performance and efficiency within its portion cal so long as they are placed to the left and of the spectrum. In addition to the Rigidflex right of the center unit. They may be spaced woofer, the Tetraxiom contains a rear- driven as much as 20 feet apart and still provide "Midax" mid -range radiator, and two pres- stereo sound with excellent spacial center -fill. sure- driven horn -londed high -frequency "Tre- The Galaxy II system provides the equivalent bax" tweeters which are angled to the polar of two complete 3 -way speaker systems with axis for wide dispersion of the highs. Because the added feature of a "derived third channel" of the massive nature of these speakers, and for eliminating the "hole-in- the -middle" effect. the need for absolute rigidity, all structural The Flexair woofer is driven by two voice coils, one for each channel of the stereo sys- tem. Frequency range of the complete system Is 36 to 14.000 cps and power rating 25 watts. Jensen Manufacturing Company, 6601 S. Lara- mie Ave., Chicago 38, III. User net price, in

handsome hand- crafted cabinet is designed on the distributed -port principle. The 25 -watt woofer has n frequency range of 30 to 8000 eps. The mid -range unit corers 1000 to 10,000 rya. while the tweeters extend from 4000 to 17.000 cps. Enclosures are available in either light Isophon Arizona finish or in dark Eng- lish mahogany. Isophon Speaker Division, Arnhold Ceramics, Inc., 1 E. 57th St., New York 22, N.Y. User net price, $295.00. IV 3 -way, 4 spkr sys $169.50 P38 15" woofer 102.50 P37 12" woofer 49.45 P16 6" mid -range spkr 8.15 P6 21/z" tweeter 7.15

76 AUDIO AUGUST, 1959 walnut, tawny ash or mahogany, $109.00; the size suitable for the average living room. The same assembly is available unfinished in kit LAFAYETTE form, $92.50. Paragon measures 8' 10" in length ; the Bookshelf Speaker Enclosure. This cabinet smaller Metregon -a similar type of cabinet- SS -100 Stereo -Director 3 -way system $179.95 is engineered to obtain optimum performance is 6'2"; and two Minigons measure 5' 4" in DS -100 Dual Stereo 3 -way system . - 369.50 from any 12-in. length, with a height -100 wide -range speaker or 12 -in: of 12h" and a depth CN 12" 3 -way system 149.50 woofer -tweeter combination with of 15% ". Two styles are available, louvered P12 -NF 12" Flexair woofer, low res no loss in 42.00 speaker efficiency. Although the design is (as shown) or with grille cloth. Both are basically that of the family of "reflexed" or designed to accommodate the Linear Effi- KLH ciency speakers, with either the 8" model being used alone, or with a 10" cone Model Seven (LE10) Speaker System. This is the used in conjunction with an LE30 high - newest in the KLII line of integrated speaker frequency driver and an LX3 dividing network systems. Enclosed in a sealed cabinet matched -a system designated S -5. James B. Lansing to their acoustic requirements are a 12 -in Sound, Inc., 3249 Casitas Ave., Los Angeles acoustic -suspension woofer and two newly- 39, Calif. User net prices : Minigon enclosure alone, $120.00; with LES speaker installed, (D46LE8) $177.00; with S5 system installed (D46S5), $243.00. LE10 10 -in. I.f. driver $52.80 LE30 High -frequency driver 52.80 LX3 Dividing network I7.40 NORELCO Speaker Series. Illustrated is Model AD- 5277M, the most powerful in the new T -7 series of twin -cone speakers manufactured by Philips of The Netherlands, and featuring "ported" enclosures, there are two unique Ticonal 7, a high- coercivity alloy which pro- departures. These are an elliptical port and a vides the highest possible concentration of triangular -shaped diffracting ring mounted flux densities in the voice -coil air gap. Weight on the front of the baffle board. These features for weight. Ticonal 7 is said to be about 30 serve to broaden the frequency response, im- per cent more powerful than any of the con- prove transient response, and create a "lens" ventional magnet materials used in speaker effect, changing relative particle velocities construction. Voice -coil impedance of the new and, consequently, phase relationships so as T-7 speakers is held constant throughout the to produce a smooth transition from front to rear radiation. Lafayette Radio, 165 -08 Ave.. Jamaica 33, N.Y. User net price, $32.50. designed director -radiator tweeters. A built -In L -C crossover network contains a 3- position switch for increasing or decreasing high - JAMES B. LANSING frequency level by 3.0 db. Enclosure volume is 2.6 cu. ft. Full -range frequency response "Linear Efficiency" Speakers. The Lansing of the Model Seven permits reproduction of Model LES is n remarkable new full -range the entire musical spectrum with a degree of transducer of unicue design. Engineered realism which is unsurpassed. Power handling specifically for small enclosu.es or infinite capacity is 75 watts of program material. baffle mounting, the performance of the LES Impedance is 8 ohms. Dimensions are 261/4"11 in an enclosure of only 1 cu. ft. is outstand- x21 % "wx11?{, "d. KLH Research and De- ing. Smallest of the new JBL "Linear Effi- velopment Corporation, 30 Cross St., Cam- ciency" components, the LES delivers full bridge 39, Mass. User net price, walnut ana bass by means of its exceptionally long linear oiled- walnut finish, $203.00; unfinished wal- nut, $198.00; mahogany and korina, $196.00; unfinished birch, $189.00. FOUR 2 -way spkr sys, mah $209.00 SIX 2 -way spkr sys, mah 119.00

KINGDOM LORENZ entire frequency range by means of a copper ring fitted into Wide -Naupe 12 -in. Speaker. Although mod- the air gap. The ring acts as a shorted turn which induces a estly priced, the Kingdom Lorenz Model S- current op- 1288 posite in polarity to that flowing through the offers no compromise In impressive per- voice formance. When properly housed coil, which reduces that current, thereby it has a lowering the impedance to its proper level. The resonant frequency of the T -7 speakers is very low, resulting in an extremely straight response curve in the bass region. In addi- tion to the cone for low and middle notes, the speakers are equipped with a high -note cone which extends the upper frequency range. Model AD -5277M is a 12 -in. speaker travel. It will produce high with a frequency range of 35 to 18,000 cps sound intensity and 20 -watt in a large room when driven by only 1.0 watt continuous power handling ca- of amplifier power. Voice -coil diameter pacity when properly housed. Cone resonance is 2-in. is 35 cps. and free -air cone resonance is 37 cps. Power High Fidelity Products Division, handling capacity is 20 watts North American Philips Company, Inc., Hicks- continuous. For ville, N. Y. excellence of performance in n compact en- User net price, $72.50 closure. the LES is unsurpassed. James B. 1 Integrated spkr sys $150 -160 Lansing Sound. Inc.. 3249 Casitas Ave.. Los 2 End for 8" spkrs 50-60 Angeles C9. Calif. User net price. $57.00. 3 End for 8" spkrs 31 -35 RJ "Minigon" Loudspeaker Housing. One of several types of cab:nets designed to match RJ /Wharfedale Speaker System. Combining the RJ the Linear Efficiency components, the JBL- /8 enclosure with the Wharfedale Super 8 /FS /AL speaker, frequency range of 18 to 1:-..000 cps because Ranger Mingon serves as an ideal unit for this compact assembly Is of dual -cone construction. Fully tropicalized monophonic reproduction. and when placed for operation In any climate, end -to -end as a pair brings the principle of the it is built on a well -known non -resonant cast -aluminum girder -con- JBL- Ranger Paragon down to a structed frame. Twin voice coils have impe- dance of 4, 8, or 16 ohms ; one coil may be connected to each of two stereo amplifiers to provide a common woofer for the two chan- nels. Magnet assembly weight is 61.5 oz. Power rating is 30 watts peak. Kingdom Products, Ltd., 514 Broadway, New York 12, ideally suited N.Y. User net price, $44.50. for stereo music systems. The EJ enclosure, when it was introduced six Omega -1 sys w /12" woofer, 2 tw $109.50 years ago, established an entire class of prod- Kai Audette sys w /8" spkr, tw 49.50 ucts. Tite RJ is distinguished from all other Audette Sr. sys w /8" woofer, tw 69.50 small -size speaker enclosures by S888 8" wide -range spkr a unique in- 21.50 ternal design, which is covered by two U.S.

AUDIO AUGUST, 1959 77 DUAL GLASER -STEERS MIRACORD Deluxe Changer -Turntable. The United Stereo Record Changer. The GS Seventy - Automatic Record Changer. Equally suit- Audio DUAL -1006 is a precision -built machine Seven is precision -engineered, completely able for stereo or monophonic application, the in all respects. It will track and operate auto- automatic in operation, and offers new fea- new Miracord Model XS -200 is an automatic matically with stylus force as low as 1.5 tures and refinements which enhance the en- turntable when its manual spindle is in posi- grams. Operating at all four standard speeds, joyment of stereo records. at the same time tion, and a fully automatic intermixing It in.,,rparates a motor of unusually high allowing enjoyment of monophonic records to changer when the Miracord "Magic Wand" the utmost. Stylus force is variable over a wide range with easily accessible vernier ad- justment. Variation of stylus force between first and last record on n stack is less than 0.9 grain. The damped. acoustically isolated tone arm is not resonant within the audio

power, assuring Constancy of speed under any spindle is used. Irrespective of whether it normal load condition. Field coils are tropical - is used as a single- record player or as a ized, and thorough shielding prevents hum. changer, the unit is push- button controlled The lightweight tone arm is of one -piece con- with no need for ever touching the tone arm. struction and is equipped to accommodate in- Every function -Stop, Repeat, Filter, Pause, by means a lock - terchangeable cartridges of Start -Is controlled by push bottons. The jam - ing -key snap-in arrangement. Direct set of proof arm returns to rest after each record. ball bearings in both axes insures freedom of A 41/2-lb. cast turntable assures constant lateral and vertical motion. Finger -tip stylus - range, and moves both laterally and vertic- speed with minimum flutter and wow. Hum is force adjustment is mounted directly on the ally on pin -point bearings. Rumble, wow, and reduced to negligibility regardless of the type tone arm assembly. Patented roller-feeler flutter have been reduced to insignificance by of cartridge employed. A 4 -speed player, the guide in the tone -arm head permits the 1006 improved motor design. As in earlier Seventy XS-200 is equipped with a heavy -duty 4 -pole to operate automatically and intermix, re- Seven models, the turntable pauses during a motor which is spring -suspended to minimize gardless of record size. Fast change -cycle time change cycle, and resumes motion only after vibration. All adjustments can be made with- is constant irrespective of operating speed. A the stylus has been lowered to the next record, out tools. Precision -built by ELAC in Western stereo -mono switch introduces a phase- cancel- to reduce stylus and record- surface wear. The Germany, Miracord products are distributed ling feedback remove vertical signal circuit to idler disengages automatically in "off" posi- exclusively in the United States by Audio - when stereo cartridge is used to play mono- tion to prevent wow caused by flat spots. A gersh Corporation, 514 Broadway, New York phonic records. Notwithstanding its many dual -channel muting switch and R -C network 12, N. Y. User net price, less cartridge, $67.50. features, the DUAL 1006 is simple to operate, maintain silence for both stereo channels dur- only three push buttons being used to govern ing record change and at shut -off. Glaser - XM5 -210 man player w/4 -pole motor $ 4750 start, stop, reject, and repeat functions. A Steers Corporation, 155 Oraton St., Newark, muting switch assures silence during chang- N. J. User net price. less cartridge, with two ing cycle. United Audio Products, 202 E. 19th cartridge shells, $59.50. THORENS St., New York 3, N. Y. User net price, $69.95. GSC cover for GS -77 9.75 Record Changer. The Thorens Model CD- 43NS combines speed accuracy, silence, and a GARRARD unique combination of operating features. It LESA is wired for stereo. A three -speed machine, it Model RC88 Record Changer. The precision is equipped with a "fine- tuning" knob for watch -like construction of this 4 -speed auto - Four -Speed Record Changer. Fully auto- exact pitch adjustment. Incorporated is a mattc and manual record player suits it for matic, the new Lesa Model CD2 /21 record association with the finest of high- fidelity changer has only two controls for all operat- components. Rumble is so low that it ap- ing cycles, speed selection, start, stop, reject. proaches the minimum standards for in a pro- Up to eight records of any size may be played fessional turntable. All levers are machined to with automatic intermix. For manual opera- close tolerances and are fully adjustable; easy tion, the record balance is simply moved to and inexpensive to service. Heavy steel table its side position. When operated manually, minimizes wow and reduces possibility of hum the tone arm is returned to rest automatically pickup when using magnetic cartridge. A after each record. A built -in click suppressor 4-pole shaded "induction- surge" motor further reduces the chance of hum pickup and assures constancy of speed with vibration eliminated for all practical purposes. Interchangeable plug -in pickup shells accommodate all stand- ard cartridges. Stylus pressure adjustment is Mir easily accessible from top side of mounting board. Manual play, with tone aria disengaged pause and reject control permitting immediate from changer mechanism, is accomplished by record reject plus adjustable pauses between records. The machine plays 12 -, 10 -, and 7 -in. records, automatically intermixing 12- and 10 -in. records when desired. Control is in- cluded for manual operation. A rugged 4 -pole direct -drive motor is equipped with mechanical filter to reduce rumble content. The changer automatically shuts off after the last record in a stack has been played. Operates on 50- or 60 -cycle a.c., any voltage from 100 to 250 volts. Thorens, New Hyde Park, N. Y. User net price, $79.95. TD -184 4 -sp semi auto player 75.00 TD -I34 4 -sp manual player $ 59.95 eliminates switching noises by means of an R -C network. A 4 -pole, carefully balanced, heavy -duty motor drives the CD2 /21's turn- table which has an exceptionally high moment of inertia. The tone -arm mechanism is jam - proof, the arm capable of being moved or LOOK FOR THIS SECTION means of a switch ; arm returns to rest after handled at any time without damage to the each playing. Muting switch eliminates noise record changing cycle time cycle. An mechanism. The NEXT MONTH through speaker during changing of 6 seconds is the same for all record sizes aluminum true -tangent tone arm provides and speeds. Pre -wired for both monophonic rigidity, low resonance, low mass, aand light Lesa changer is changer, and stereo operation, the weight. The RC88 is an excellent equipped with a universal plug -in shell which AND ARMS, worthy in all respects of its reputation. accommodates all standard cartridges. Elec- PHONO PICKUPS Garrard Sales Corporation, 80 Shore Road, trophono & Parts Corporation, 530 Canal St., Miscellaneous Accessories Port Washington, N. Y. User net price, leas York 13, N. Y. User net price, $39.95. cartridge but with two universal plug -in New shells, $54.50. 4V3 /I1 4 -sp man rec player $ 2325

1959 80 AUDIO AUGUST, PHONO TURNTABLES ARGONNE REK -O -KUT Hysteresis Turn table. Employing a true hysteresis motor. this new single -speed turn- Hysteresis -Motor Turntable Kit. Meeting table will maintain a constant 33%-rpm professional standards throughout, the Model K -33 -H turntable kit can be assembled speed irrespective of normal load or line - in 30 minutes or less. using voltage fluctuation.. The 12 -in. 4t,ß -lb. die - only simple tools. A cast riot -weighted aluminum table turns on a single -speed unit (3:t';, rpm), it features a high -efficiency I,y,t,re.is synchronous motor

with a pressure lubricating system. Handsome black, whit,, and chrome styling. Garrard Sales Corporation, 80 Shore Road. Port Wash- ington, N. Y. User net price, $59.50. GRAY Precision -Built Turntable. Developed to de- feat the rumble problem which came with the introduction of stereo records, the Gray 33 -H incorporates an unusual bearing -shaft as- sembly which reduces vertical motion to negli- built to Rek- O -Kut's exacting specifications. gibility. Wow and flutter are well within Noise level is 52 below average recording level. NARTB specifications for professional equip- The precision ball bearing crown -spindle belt drive uses a custom - and is engaged by means ment. A unique motor suspension virtually made endless -woven fabric belt with of an oversize heavy -duty idler wheel. thickness Wow held to +0.001 in. An adjustment is supplied and flutter components are less than 0.2 per for belt Tension. cent, and signal -to A built -in strobe disc permits -noise ratio is better than constant speed check. The solid cast -aluminum 45 db, The unit is supplied with a heavy turntable is lathe rubber turntable mat and mounting -turned, and tapered for template. easy disc handling. The entire assembly is Dimensions are 13%" x 14%" x 6% ". Argonne finished in -tone Electronics Mfg. silver aluminum. Where econ- Corp., 165 -11 South Road, omy must be observed. K -33 Jamaica 33, N. Y. the -H presents an ideal means of possessing a high quality turntable at modest cost. Rek -O -Kut Company, CONNOISSEUR Inc., 38 -19 108th St., Corona 68, N. Y. User net price, $49.95. Transcription Turntable. Built throughout to professional standards. the Connoisseur N -33H 33 1/3 w /hys sync motor .. $ 69.95 Type B turntable is a three -speed machine K -33 331/3 w/4 -pole motor (kit) 39.95 suitable for playing B -12H 3 -sp w /hys sync motor 129.95 both monophonic and B -12 3 -sp w/4 -pole motor 84.95 stereo recordings. The full 12 -in. table is lathe - turned and manufactured of non- ferrous ma- terial. Underneath the table a large strobo- eliminates vibration. A single -speed (33% H. H. SCOTT scope disc is fitted, this being viewed through rpm) machine, the 33 -H is driven by a hyster- a reflecting mirror with a built -in light source. esis synchronous motor through a stretch belt Stroboscopic Turntable. Developed primarily Speed change is arranged mechanically and drive which further reduces vibration caused to meet the demanding requirements of stereo, by mechanical coupling. Gray Manufacturing the Type 710 -A turntable employs a radically Company, Inc., High Fidelity Division, 16 new design which isolates the table proper Arbor St., Hartford, Conn. User net price, from all extraneous mechanical vibration. It $79.95. The Gray HSK -33 turntable kit con- features push -button selection of 33%-, 45 -, tains the same engineering features as the or 78 -rpm operating speed. Each speed has 33 -H except for smaller mounting plate. As- its own vernier adjustment and may be varied sembly time is 25 minutes. User net price, $49.50. PICKERING "Gyropoise" Turntable. Engineered specifi- permits a four per cent variation on all op- cally for microgroove erating speeds. All revolving records -both mono- shafts are pre- phonic and stereophonic -the Gyropoise 800 cision ground and lapped to mirror finish. Stereotable Bearings are made adjustable is a single -speed machine operat- so that full ing at 33% rpm. It embodies a unique method servicing can be performed throughout the of magnetic suspension, machine's life. The synchronous motor on which patents are is pending, which eliminates vertical rumble to dynamically balanced and resiliently mounted, the making it vibrationless. point that it becomes inconsequential in virtually Rumble is the playing of stereo records. Vertical stated to be down 50 db, and wow is less than period of spring suspension is below 5 cps ; compound 0.15 per cent at rated speed. Manufactured vertical rumble by A. R. Sugden and Company of Brighouse, attenuation is 12 db /octave below resonance ; noise is 65 db below refer- Yorkshire, Eng., the Connoisseur Type B ± 5.0 per ence level ; speed accuracy cent to match pitch of accompanying turntable is distributed exclusively is +0.2 per cent in the total variation. Pickering & musical instruments. A built -in expanded -scale United States by Ercona Corporation. Company, Inc., 16 W. Plainview, N. Y. User net price, chassis only, optical stroboscope permits exact speed ad- 46th St., New York 36, N. Y. User net price, justment even while a record is $119.50. $59.95. Model 800CB, complete base, in ma- being played. hogany, walnut or blond, $15.00. Motor rumble is more than 60 db below record- ing level, and wow and flutter are less than 0.1 GARRARD per cent of rated speed. Precision nylon heli- cal drive gear and steel worm are housed in Deluxe Manual Record Player. The Garrard permanently oil -filled transmission. A special Model 4HF constitutes a 12 -in. turntable clutch permits cueing. H. H. Scott, Inc., 111 complete with transcription -type arm mounted Powder Mill Road, Maynard, Mass. User net on a single unit plate. It is fully wired for price, $129.95. stereo or monophonic operation. Although modest in price, the 4HF affords most of the features usually expected only in equipment THORENS considerably higher in cost. Variable speed Transcription Turntable. adjustment is available on each of Engineered for the four the finest music systems, the Thorens Model standard operating speeds. Automatic start - stop is built into the TD -124 is a four -speed machine featuring a tone arm rest. A newly - full 12 -inch, 11%-pound table designed center spindle housing is equipped for lowest wow and flutter. The main table is made of cast

AUDIO AUGUST, 1959 81 and easily accessible levelling screws. The precision 4 -pole motor is equipped with a compliant belt- plus -idler arrangement which provides excellent motor vibration isolation. The TD -124 operates on 50 or 60 -cycle n.c. nt any voltage from 100 to 250 volts. Thorens, New Hyde Park, N. Y. User net price, $99.75. TDK -101 331/3 rpm kit 47.50 WEATHERS LightrrcighI Turn fabla. Engineered especi- ally for modern phonograph pickups having wide -range response and low tracking force, acoustic feedback are eliminated for all prac- this turntable is manufactured of light alumi- tical purposes. The table is a single -speed num and is suspended on a hearing assembly 3354. -rpm machine, however additional speeds iron to provide shielding against hum pickup. means of the Weathers unique design to offer a nilnhnum of fric- may be obtained by A cover table made of aluminum, plus an of Type P -620 Electronic Speed Control which attractive rubber mat, mitigates the attrac- tion. The table is driven by a 12 -pole syn- has been designed for broadcast station use. tion of magnetic pickups. Precision- machined, chronous motor of very small size but of Rumble is down 70 db, flutter is 0.1. per cent, the morons Roto-Drive is adjustable ± 3.0 per adequate torque to drive the machine at exact and wow is 0.15 per cent. Weathers Indus- cent for exact musical pitch. A built -in il- speed regardless of line- voltage variation or tries, 66 E. Gloucester Pike, Barrington, N. J. luminated strobe allows setting to exact speed normal variations in load. Noise level is 25 User net price, ML -1 Turntable, $59.95. while record is playing. Easy levelling is ac- db less than the noise recorded on high K601 33 1/3 rpm rec player $111.75 complished by means of a built -in level-bubble quality phonograph records. Rumble and KL -I Same as ML -1 in kit 34.50

TAPE EQUIPMENT quency range at 3% ips is 30 to 15,000 cps. controls govern all operating functions. Wow AMERICAN CONCERTONE Its precision -engineered timing accuracy is and flutter content is under 0.25 per cent. Professional Stereo Tape Recorder. A ma- such that it offers perfection of pitch held Playback frequency response is stated by the chine of advanced design, the Concertone to tolerances of one -third of a half -tone. manufacturer to be 50 to 15,000 cps. This Mark VII records and plays back 2 -track stereo Flutter and wow content is under 0.2 per unusual response figure for 3% -ips operation and monophonic tapes; the Mark VII -F in cent rms at 7% ips; under 0.25 per cent nt is achieved by means of a head gap width of addition will play back 4 -track stereo and 3% ips. Dynamic range is 55 db and 50 db at only 90 millionths of an inch. The Stereo -Pak monophonic tapes. Featured in the Mark VII preamplifier equalization circuits are espe- series is a direct -drive capstan motor and cially engineered to take maximum advan- 4 -pole induction -type reeling motors. Manu-

the higher and lower speeds, respectively. High- impedance inputs are provided for factoring tolerances are stated by the manu- microphones and high -level program sources. facturer to be within two millionths of an Cathode -follower output is approximately 0.5 inch. Push -button controls are solenoid -oper- volt. Azimuth alignment of stereo head gaps ated. Automatic reel -end cut -off switch pre- in the same stack is within 20 seconde of an vents tape runaway. Self- energizing brakes arc, equivalent to less than 10 millionths of tage of the head characteristics. All models assure smooth operation without tape stretch. an inch. The appearance of the 960, in a of the Stereo -Pak incorporate a completely Dual inputs are supplied for microphones and carrying case, is transistorized stereo record -'playback pre- distinctive gray portable hum and auxiliary devices. Four separate level controls well in keeping with its impressive per- amplifier with exceptionally low and master gain control permit mixing of all formance. Ampex Audio, Inc., Sunnyvale, noise. Illustrated is Model 405, which includes inputs. Frequency response is 30 to 17,000 cps Calif. User net price, $650.00. built in 14 -watt (7.0 watts on each channel) +2.0 db at 755 ips. All standard reel sizes up stereo power amplifier. An accessory speaker to 10%-in. can be accommodated. Lightweight Matching Amplifler- Hpeaker. Engineered for system, Model 450, is available as a matching for easy portability, the Mark VII weighs use with the Model 960 recorder is the Model accessory. Bell Sound Division, Thompson only 39 lbs. in portable carrying case, includ- 2010 amplifier -speaker. Matching the 960 in Ramo Wooldridge Inc., 555 Marion Road, ing record and playback preamplifiers. Ameri- size and appearance, the 2010 amplifier sec- Columbus, Ohio. User net price, $299.95 ; can Electronics, Inc., Audio Division, 9449 W. tion provides operating characteristics flat Accessory speaker system, per pair, $49.95. Jefferson Blvd., Culver City, Calif. User net within ±1.0 db, with total harmonic distor- Mark VII in portable carrying case, cent, throughout the T210 mono rec /pb $109.95 price, tion less than 0.5 per T211 mono pb, 1 tr ster pb 119.95 $940.00; Mark VII -F, $895.00. maximum range of human hearing. The spe- y tr ster pb 129.95 smooth 7212 mono rec /pb, Mk. X -3 Bdcst Rcdr, Stet rec /pb . $1050.00 cially-designed 8 -in. speaker provides 7213 mono rec /pb, IY2 tr ster rec /pb 149.95 X -1 Bdcst Rcdr, Y2 tr. mono rec /pb 965.00 peak-free response throughout n remarkably 270 Spkr /amplifier, in case 188.00 wide audio range. User net price, each (two required for stereo playback), $199.50. E.M.I. AMPEX Battery -Operated Tape Recorder. This Home Tape Recorder. Although it is classi- BELL lightweight portable recorder makes possible fied primarily as a home -type instrument, the the reproduction of sound with a fidelity Ampex Model 960 meets professional record- Cartridge Player-Recorder. Bell "Stereo - comparable to that of professional studio ing standards throughout. It is a highly Pak" tape -cartridge players and recorders equipment. Weighing only 14% lbs., including of almost have been designed to accommodate the new only 14" x 8" x 7 ", versatile stereo machine capable 4- batteries. and measuring of operation. Capable of RCA -type stereo tape cartridge. Using the L -2 uses standard 5 -in. any desired mode ips, the user the E.M.I. Series recording and playing back half -track mono- track cartridge at a speed of 3% reels of quarter -inch tape and requires no tape and two -track stereo tape, it will can obtain up to a full hour of stereo sound power source. It is available in phonic Use of moving external when desired. on 600 ft. of 1.0 -mil tape. : for 30 minutes ; 7% also play back four -track tape to an three models 3% fps 960 will record a frequency range of 30 parts in the Stereo -Pak has been kept ips for 15 minutes, and 15 ips for 7% min - The minimum to insure dependable and to 20,000 cps with distortion reduced to absolute (Continuerl on page 105) negligibility at 7% ips operating speed; tre- trouble -free operation. Only two mechanical AUDIO AUGUST, 1959 82 New H.H. Scott

CROSSOVER Stereo Amplifier has AND BIAMPLIFIER features never before (front page 48) Operation offered at $139."55' Selection of the best crossover fre- quency is done by listening tests only. The gain controls should be adjusted The new H.H. Scott 24 watt stereophonic amplifier, Model 222, for best balance of treble to bass. These puts top quality within the reach of all. This new amplifier has many controls should be readjusted each time the crossover frequency control changed. features never before available for less than $200. It is backed by It is best to adjust the gain controls to a high level, and eut the input signals H.H. Scott's fine reputation. Check the features below and you'll by turning down the level controls in see why you should build your new stereo system the preamplifier. The author recorded around th#+ all settings of the gain controls for each H.H. Scott Model 222. setting on the crossover frequency con- trol so that previous listening tests could be duplicated for comparison. A few words about the speakers used with this amplifier. The author's speaker system includes four speakers. A good quality 15 -inch woofer in a back -loaded folded horn is directly connected to the bass amplifier. The middle- and upper - frequency speakers include two 8 -inch speakers mounted in the upper section of the same cabinet. Within the same compartment as the 8 -inch speakers is a horn type tweeter with a 3000 cycle L -C high pass filter. This arrangement is connected directly to the treble ampli- fier.

Building the amplifier described in Equalization switch lets Separate Bass and Effective scratch filter Channel balance con- Master volume control this you choose between Treble controls on improves performance trol adjusts for dif- adjusts volume of both article was quite a job. However, RIAA compensation for each channel let you on older worn records ferent speaker effi- channels simultane- results have shown that it was well worth monophonic and stereo adjust for differences and improves recep- ciencies and brings ously. Also functions as records; NARTB, for in room acoustics and tion on noisy radio channel volumes into automatic loudness while. Until somthing new comes along, tape different speaker sys- broadcasts. balance quickly and control whenever de- tems. / easily. sired. I think this is it !-and the little wife Special switch posi- This position lets you Exclusive center- hopes so. tions for accurate bal- play a monophonic channel output lets you ancing, for playing source such as an FM use your present amp. stereo, reverse stereo tuner or a tape re. liter for 3-channel PARTS LIST and for using mono- corder through both stereo or for driving phonic records with power stages and extension speakers. All resistors are 1 watt unless otherwise your stereo pickup. speakers. Separate stereo tape - specified. recorder outputs. Rn R,, 500 k -ohm pot, linear R,, RH, R 220 k ohms SPECIFICATIONS: Dual 12 watt channels 0.3% IM dis- R,, tortion ; 0.8% harmonic distortion ; frequency response 20 to 30,000 cps; ex- R. 2200 ohms tremely low hum level (- 80db); DC operated preamplifiers heaters; Inputs for Ru Ras 39 k ohms stereo or monophonic recorders, tuners, phono cartridges and tape heads. Rs, Ras 2.2 megohms Phono sensitivity 3 mv. Sub -sonic rumble filter prevents overload from noisy changers or turntables. Price R,, R,1 470 k ohms $139.95 R,, R 1500 ohms H.H. SCOTT INC. Dept. A.B. 111 Powdermill Road, Maynard, Mass. Export: Telesco International Corp., 36 W. 40th St., N.Y.C. Ra, R,, R,,, R,, 22 k ohms R,,, Ru 2200 ohms, 1% Insist on genuine H. H. Scott components. R,,, R 25 k -ohm pot (see text) R,,, R,, 8200 ohms, 1% *West of Rockies $149.45. Accessory case entra. R,,, R,, 100 k -ohm pot (see text) R,,, R 10kohms R,,, Rs, 270 k ohms R,,, R,, Re, 680 ohms R,,, Rar 47 ohms SEND NOW FOR Rush me complete details on your new Model 222 and R 1200 ohms your complete 1959 Hi Fi Guide and Catalog. Dept. A -8 R,,, R,s 1.2 megohms FREE HI -FI GUIDE Rro, R,s 47 k ohms Rr» R+ri Rsr, R,e 47 k ohms (matched AND CATALOG pairs) Name R,,, Rr, 100 k ohms Address BIG, Rrc 100 ohms City State Rn 100 -ohm, 4 -watt pot Rm, Rrs, Ru, AN 1000 ohms

AUDIO AUGUST, 1959 Dr. Kenneth Eldredge. noted Electronic Consultant and Research Director. puts SARGENT- RAYMENT equipment through an intensive series of performance tests in one of the West Coast's most advanced electronic laboratories.

` From s minals .. e SARGENT - RAYMENT has the LOWEST COMBINED DISTORTION of any stereo system available today, at any price

It is easy to claim superiority -difficult to prove it. But there is one proof that passes every test -the proof of performance. This is what SARGENT - RAYMENT has to offer, and is why SARGENT- RAYMENT components are fast becoming the stereo standard of comparison. To engineer and music lover alike, SARGENT - RAYMENT Stereo offers performance all out of proportion to its price. Judge it yourself, with the one test that's undisputable -your own ears. Hear it at your Component Hi -Fi Dealer's today. SARGENT RAYMENT CO. .4926 East 12th Street, Oakland 1, California Please send FREE 12 -page technical brochure describing S -R Stereo Reproducers. HI-F1's BEST GUARANTEE S -R Stereo Reproducers are backed Name by the industry's best Guarantee... Address 15 MONTHS City & State

84 AUDIO AUGUST, 1959 TB' 1112 2 F RIf 0.5% R47 aN x o V R13 Ce Te ll Ce CC o f CO 100 R49 KC CKC FREQUENCY IN PER CYCLES SECOND TB4 TB3 FM distortion through entire audio band at full modulation R58 R21

R57 R22

R54 R24 IX z U O_ R55 R23 2f R51 R26 ON I 0.5% ¢O aN R52 R25 R60 132 o R59 R33 0 20 40 60 80 100% PERCENTAGE OF MODULATION R53 j R18

AM distortion of special C24 C8 S -R two -tube detector

1% Fig. 7. Layout of components on the resistor mounting boards, and the indicated sections of the crossover- frequency control. 0.8% 0.6% 0.4% R,,, Rc, 300 ohms, 20 watts, L, 4 -]Ty. choke, 200 ma 0.2% adjustable T, Ultra -Linear output, l R,,, R 5600 ohms, 2 watts Acrosound TO -300 O R,2, R. 25 ohms (matched) T, Ultra-Linear output, O IV 2v 3v 4V 5V R,,, R4, 22 k ohms, 2 watts Dynaco A -430 IM. DISTORTION VS VOLTAGE OUTPUT R 1000 ohms T, Thordarson 221/35 R,,, Rc, 100 k ohms (matched) T4 117-v primary to 117-v Tone control, high voltage -low- R 12 ohms, 1% secondary, 35 ma distortion cathode follower output RG, 18 k ohms, 2 watts CR, Selenium rectifier, R, R. 10 k ohms, 2 watts Federal 1002A, 65 ma R 5000-ohm pot, 4-watts 1r r, 12AU7 tube I% R,o 6800 ohms, 2 watts P P, 6AN8 tube R 100 k ohms, 2 watts 1' V, KTGG tube 0.8% C,, C .05 µf, 600 volts P F, EL34 tube C, .03 µf, 600 volts 0.6% F F 5V4GA tube C,, C4 10 µf, 475 volts, J, Phone jack, Amplienol 0.4% electrolytic 80 -C C, 0.1 µf, 600 volts, 1% 0.2% C, .024 µf, 600 volts, 1% Ca C,e, C,,, C 20 µf, 450 volts 0 electrolytic 0 IO 20 30 40 5OWATTS Cs, C,4 680 µµf, 400 volts TECHN ICAL DATA C,,, C,,, OA µf, 600 I.M. DISTORTION VS WATTS OUTPUT C C, C. volts Power output: C,,, C. 40 µf, 150 volts, electrolytic Treble channel 20 watts Amplifier output with all tubes Bass channel watts .25 µf, 600 volts 50 being driven within recommended Cu, C Power input 222 watts, .0431.4f, 600 volts, 1% operating voltages Ceo 117v C .01 µf, 500 volts, 1 %, mica Input voltage for 12 watts output, crossover 20 µf, 475 volts, at 500 cps Cn, C. Treble electrolytic channel ... 0.7 volts Bass channel .... 0.9 volts Photo at left and curves above refer to C. 390 µµf, 1000 volts, ceramic Hum: SARGENT -RAYMENT SR -1000 AM -FM C,,, C. .25 µf, 600 volts Treble channel ... 95 db below Stereo Tuner ($184.50). SR -1000 Master (matched) 20 watts Stereo Preamplifier ($163.50), and SR- C 50 pf, 50 volts, Bass channel .... 80 db below 5100 dual 50 -watt Stereo Power Ampli- electrolytic 50 watts fier ($183.60). These and other S -R C , C. 40 µf, 500 volts, Crossover data: stereo equipment fully described in free electrolytic Frequency range . 100 to 1,200 cycles 12 -page brochure available through C , C. 30 pf, 475 volts, coupon at left. electrolytic Attenuation 8 db (approx./ C,,, C 0.1 ltf, 600 volts, bathtub per octive 2 x 0.1 Note: Test equipment was not available for F, 5 amperes, Littelfuse intermodulation tests. 3AG Total harmonic distortion was less than 2 %. However this was for the F, 1/ ampere, Littelf use entire system (using a Test Record). 3AG

AUDIO AUGUST, 1959 85 is his first big band date in more than a den ade, and the major role he assumes in the music for television's "M Squad." Although he shares the writing about equally with Johnny Williams and Stanley Wilson, the musical di- rector, his alto sax weaves assuredly through solos on nearly every number and is especially compelling on A Lady Sings The Blues. Con- sidered as jazz, the score is the most mer- ¡tons to emerge from the private -eye dramas. Recorded by Al Schmitt at RCA Victor's new Music Center of the World, the sound strikes a happy medium between that of most re- cording studios and the larger movie sound stages. Carter salutes the months of the year on his big band session, composing four originals to fill out the requisite amount. The personnel lists the familiar names of Hollywood studio musicians, including Shorty Sherock. Pete Candoli, Buddy Collette, Barney Kessel, and andl/Nitat. . Here his characteristic setting for the entire sax section, balanced admirably in stereo, is as rewarding as the featured so- CHARLES A. ROBERTSON* los. Ideal for dancing, it offers a pleasant change from most West Coast units. STEREOPHONIC piano performed on schedule. Either is to be preferred in stereo, but those who want both Bill Evans: Everybody Digs Bill Evans may be satisfied to take one in monophonic George Gershwin At The Piano form. Riverside Stereo RLP 1 129 20th Fox SFX3013 Among a sampling of other piano -roll spe- All the elements which make Bill Evans a Piano Roll Discoveries cialists, Victor includes, in addition to Gersh- musician's pianist are winningly exhibited on RCA Victor LSP2058 win's major opus, his version of Whose Baby his second . Gifted with a fine and sen- Are Your A second look at the label may be sitive ear for melody, he combines a concise, When entertainment in many homes cen- required to convince you that the question impeccable touch with an unfailing sense of tered on the player piano, Aeolian Duo -Art comes from Jerome Kern. A younger genera- rhythm. On Peace Piece, a long original solo 'was one of the most famous imprints of the tion, fresh in the knowledge that Thelonious excursion, he passes around a set of varia- time, claiming the same respect as trade Monk sometimes lampoons Zez Confrey, can tions in the impressionistic style first brought mames on high quality audio components en- learn the rest of the story as related on to jazz piano in the compositions of Biz joy today. Where the ordinary pianola clat- Stumbling, a piece of his own devising, and Beiderbecke. In other hands, a notable ex- tered away with unvarying clangor, unless The Sheik of Araby. For those who do remem- ception being Jess Stacy, this approach is the operator was a skilled manipulator of ber, the rewind and flapping noise at the end often refined into amorphous wandering that Thoth foot -pump and pedale, the Duo -Art was of a roll are retained. bears little relation to jazz or Debussy, from fed nuances of phrasing and dynamic shading Other composers playing their own works whom it stems. Evans restores its masculine from a series of holes along the sides of the are Felix Arndt on Nola, Lee S. Roberts and vigor, renewing it through a telling use of roll. The company staged blindfold tests dur- Max Kortlander with Smiles, and Fats Waller modern phrasing. Also unaccompanied are ing the Twenties that were forerunners of on Squeeze Me. Of most worth to jazz students Lucky To Be Me, and a brief Epilogue. the current "Live vs. Recorded" concerts. is the daddy of them all, James P. Johnson, Otherwise, his companions are Sam Jones, Among the pianists it employed was the stating J Ain't Givin' Nothin' Away, and Vic- bass, and drummer Philly Joe Jones, who youthful George Gershwin, who made rolls tor can do no better than locate enough of curbs any tendencies to become overpretty on for a decade, beginning in 1915, and near the the rolls he and Waller cut to make up a se- Night and Day, Tenderly, and Young and close of the period cut his own reading of the quel. Foolish. The trio is joined effectively in stereo. complete , a performance re- claimed on both these discs by the latest Ray Bauduc -Nappy LaMare: Two -beat The Vibe Sound Of Peter Appleyard stereo techniques. Generation Capitol ST1198 By delving also into the archives of a Audio Fidelity AFSD5901 sister subsidiary, 20th Century -Fox gives the Ruby Braff: Easy Now Terry Gibbs: More Vibes On Velvet fullest portrait of the composer at the key- RCA Victor LSP1966 Mercury 5R80027 him at four board yet unveiled, presenting When tandem, these com- stages in his career. First there is the jour- played in The amount of straight melody coaxed relaying the songs prise a pleasant sector in jazz chronology and from the vibraphone in these two efforts is neyman pianist of 1920, are with some thought for the advan- of others in true piano -roll style, as exempli- planned enough to please the most demanding must - Grieving tages of stereo placement. In fact, the Bob musicians have fied by Left AU Alone Again Blues, go hear- the -tune auditor. Both For You, Pm A Lonesome Little Raindrop, Crosby alumni based on the West Coast good reasons for not breaking into fervid but and Just Snap Your Fingers At Care. Five outside their own little group to Jack Mar- lese lyrical embellishments. Since arriving years later, just before his writing activities shall for arrangements. He provides a chase from Canada in 1954, Peter Appleyard has between two trumpets on Coffee House Rag, a the limited his professional appearances, he is his fancy gained working acquaintance with pref- playing his own compositions in the Rhapsody, and shifts the players about to suit erences of club patrons on this side of the and That Certain Feeling. Then in 1929, via before each number. His other work on this border. His first LP for local consumption is label indicates that he bas made quite a study based a knowledge of what the more lu- Fox Movietone News and the transfer from Nappy LaMare sings on optical to , he is of the problem. Guitarist crative segment of his audience demands. heard directing a rehearsal of "Strike Up The on Papa's Gone, Good Bye, and Ray Bauduc Briefly, it is the Jonah Jones formula of Band," leaving his post at the piano momen- is as sharp a drummer as ever. Gene Bolen's singing lines and a personal touch. He fills tarily to engage in banter with the comedy clarinet is pure New Orleans on My inspira- the prescription on Avalon, Just in Time, and team of Clark and McCollough. Finally in tion, and Jackie Coon alternates on trumpet 'S Wonderful. Centered between bass and 1931, the newsreel cameras pick him up and mellophone. Among the dozen tunes are drums in stereo, the vibes are crystal clear. again at the opening of the Manhattan The- Smokey Mary, and De Paris' Martinique. "It's very hard to play straight melody on atre, an occasion enlivened by his impromptu Ruby Braff, heading two casts, affords pro- vibes," is the way Terry Gibbs notes his sen- variations on I Got Rhythm. tracted examples of trumpet interplay. On six timents, "You keep wanting to play little fig- Because the familiar strains of the Rhap- tunes with a sextet, his respondent is Roy ures and things around the tune and It's sody in Blue, as orchestrated by Ferde Grofe, Eldridge, who sends back rapierlike sallies on really tough to stay on the melody." Among communica- This Is My Lucky Day, and Someday You'll his inducements are five new ballads, set to have filled the channels of mass flugel- tion for so long, many listeners have lost an Be Sorry. By switching in midstream to lyrics by his wife. He wrote four himself, and horn, he gives a firm underpinning to Braff's delivers them in slow, persuasive tempos. His early enthusiasm for the work. An opportunity added to hear the composer's original piano version lyric sentiments. In an octet, with the tones are equally subdued on Moonlight Sere- is likely to stir their interest anew. Perhaps voices of Vic Dickenson, trombone, and Bob nade, Blues In The Night, and Steve Allen's it will even convince Ira Gershwin and the Wilber, tenor sax, Braff meets Emmett Berry, Impossible. Rich saxes, arranged by Manny Gershwin Estate, whose approval 'was needed playing one original as well as My Walking Alban], surround the vibes in stereo. recordings, that a modern orchestra- Stick, and Willow Weep For Me. The horns for these blend admirably in stereo on each occasion. tion is in order. A commission to Robert Clark Terry: Top And Bottom Brass Prince, Gil Evans, Johnny Mandel, or even Stereo RLP1137 Leonard Bernstein could do much to prevent The Music From M Squad Riverside it from becoming a period piece. RCA Victor LSP2062 Noting that the relationship between the Both projects were carried out at RCA Vic- Benny Carter: Aspects trumpet and tuba is actually the same as that tor studios and an impressive list of engineers of violin and double bass, Don Butterfield pre- was involved. William Jordan and Douglas United Artists UAS5017 fers to regard his tuba as a "contra -base Williams were from 20th Fox, and Lou Lay- With the halfway mark passed, it seems trumpet." A member of the orchestra at Radio ton, Michael Crawford and Paul Hoffman rep- more than certain that this year will be re- City Music Hall, he met Clark Terry when resented Victor. Alphonso D'Artega made sure membered for the resurgence of Benny Carter the Ellington trumpet man did a guest ap- the Imperial- Industrial electric reproducing in all his many capacities. One Contemporary pearance on stage. Together they worked out album is behind him, and a second will unite the idea of combining the two instrumente in 732 The Parkway, MamaroneokkN. Y. him with Earl Hines. Also on the credit side a unique front line, enriching it further with

86 AUDIO AUGUST, 1959 the original and positive sound reproduction techniques necessary for true high fidelity are presented on CAF AUDIO FIDELITY. RECORDS the highest standard in high fidelity

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The romantic music of gay Vi- Listen to the mellow trumpet and An informative enna and fascinai ng captured in all of its tune. wailing trombones of the latest demonstration ful beauty of stereophonic by the artistry of Jo and most phenomenal of Dukes reproduction including Basile and his accordion. sounds pf of Dixieland recordings cannons. fire engines and sperts AFLP 1868 /AFSD 5868 AFLP 1892 /AFSD 5892 cars. STEREO ONLY. AFSD 5830 ...... ,._... . . ,,,,,.,,,,,,,,DIIKES OF ...... DIXIELAND ...... ,._......

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Jo Basile brings his skillful ar- The album that made dixieland The brilliant highs and dynam tistry to the haunting c beauty of as played by the Dukes of Dixie lows of the theater organ Italian song favorites for are your land. You have to hear it to musically displayed by the ve listening pleasure. -sa- believe it! AFLP 1823 /AFSD 5823 tile Al Melgard. AFLP 1871 /AFSD 5871 AFLP 1887 AFSD 5887 Complete illustrated HEAR the L.fabulous catalogs of the entire 1st Component Series Audio Fidelity library are The finest classical performances available from: available in stereophonic high fidelity Audio Fidelity, Inc., These recordings reproduce it proper Dept. A759, 770 11th balance and spatial relationships the musical elements as heard only Ave., New York 19, N. Y. before in the concert hall. SUGGESTED PRICE - $6.95 EACH 12 INCH STEREODISC SUGGESTED PRICE $5.95 EACH 12 INCH LONG PLAY - ALL ALBUMS EXCEPT AFSD 5890 ARE AVAILABLE T H MONOPHONICALLY AND STERE)PHONICALLY AUDIO AUGUST, 1959 87 the full voice of Terry's flugelhorn. He also utilizes his trumpet mouthpiece, in a light- hearted recasting of the unbridled jungle sounds of the wa -wa mute, on an original blues. Following this example, Butterfield re- moves his tubo completely from a subsidiary role, permitting it to charge like wounded rhino through a longer blues. Besides engaging in sprightly collaboration on My Heart Belongs To Daddy. they investi- gate march and waltz tempos. In evading the tuba, bassist Sam Jones' work is cut out for him, and Jimmy Jones, piano. with drummer Art Taylor completes the quintet. Butterfield states that his tuba, in the title tune, picks three up a unison B flat from Terry and descends through its register to pedal B fiat, the last black note on the piano keyboard. Quite a test for your equipment, as well as for everyone elegantly concerned in the processing, particularly Jack Matthews, of Components Corp., who made styled the stereo master. Leon Bibb: Folk Songs ultra Vanguard VSD2012 Jimmie Driftwood: The Wilderness Road RCA Victor LSP1994 co rcpac If these were jazz artists it would be im- possible to cover them tinder the same head- ing. Fortunately, the collector of folk songs spéaktr seeks broad experience and is catholic in his approach, qualities some jazz enthusiasts might well adopt. As the folk contingent is systems already hot on their trail, these new dis- coveries are grouped together because their first LPs belong in any collection. Experienced in Broadway musicals, Leon Bibb is a polished of superb performer and brings the dramatic intensity Model RRL- 1312" 3- Speaker IRL System of a to his material. It in- cludes songs from prisons and chain gangs, quality blues and love songs. He also is benefited by the accomplished assistance of Fred Heller- man and Milt Okun, who frame his voice with a guitar, harmonica or choral group, at depending upon the nature of his role. The stereo recording is splendid. Jimmie Driftwood was introduced to n modest New York audience at an Alan Lomax con- cert in Carnegie Hall, and his national fame rests on The Battle Of New Orleans, the hit cost song he revised from a 140 -year -old version. Of the dozen songs gathered here. all are MODEL RRL -12 charming hits of Americana and carry an ap- peal not dictated by hit- parade requirements. Features the sensational Some may end up there. however, notably new Sphericon Sulu r . Four Little Girls in Boston, and the tale of Tweeter for sweet, Peter Francisco, the Paul Bunyan of the smooth high frequency Revolutionary War. Besides accompanying himself on guitar. Driftwood interjects solos response to inaudibility. on the "Pickin' Bow," which is held to the 85"x 153/8"x 121/x" deep. mouth and played with a pick. sounding like From $114.95 unfinished. an oversize Jew's harp. The woodsy effect is enhanced by a Nashville recording which MODEL RRL-8 seems to have hint sing through a hollow log. The impossible becomes Stereo enlarges the log and nothing could re- realitk! An r system move the hard -cider twang from his voice. withull bass response down to below 40 cps! Highlights Of Vortex Model REL -8 3- Speaker EEL System Folkways Stereo FSS6301 $$1/4" x 18t/4 "x 103x" deep. r From $95.50 unfinished. The music of Vortex, described as a new kind of theatre, was composed for a series MODEL S-80 of sound experiments at San Francisco's Excellent wide-range Morrison Planetarium, where the audience is response from a surrounded by a circle of thirty -eight speak- system measuring only ers. An added sound source is two speakers in the center of the domed auditorium, and 213/4 "x 111/2" x91/4" deep. a control panel channels the taped com- From $56.95 unfinished. positions to any combination required. or ALL THREE MODELS selects them in series for rotational play- back. This electronic music differs from its finished on four sides parent Musique Concrete, a recent import for use as highboy or from Europe. in that it is meant to be com- lowboy. Beautiful bined with visual effects. The auditory treats on each program are accompanied by moving oiled walnut finish patterns and flashing colors obtained front for RRL -13 and REL -8 the planetariun's intricate lighting system in addition to mahogany, and a battery of Vortex projectors. Its dis- limed oak; semination throughout the globe is now in walnut and the hands of the Audio -Visual Research S-80 in mahogany, Foundation. walnut and fruilwood. Of necessity, its composers are wizards with a tape recorder, and two have close associations with the jazz world. William Loughborough, creator of the "boo Lam" and other percussion instruments, has toured 8 Efficiency System with Chet Baker to demonstrate his inven- Model S -80 r -Way High tions. His polyrhythmic study, For the Big Furniture courtesy of Smilom- Thielle Corp. Horn, had its initial playback through an PLAINS, N. Y. exponential loudspeaker which he built with WRITE FOR FREE LITERATURE PESE R -5. UNIVERSITY LOUDSPEAKERS, INC. WHITE AUDIO' AUGUST, 1959 88 a mouth twelve -feet in diameter. Henry Jacobs, originator of the project with Jordan Bellson, is known In another Incarnation for his research into the weird life of Shorty I'etterstein for World -Pacific. His works in- cluded are a film sound track, two mood pieces, and a study in amplified Haitian drums and Indian tabla. An employee of the Ampex Corporation. Gordon Longfellow gives the name of one of its prize products to Three Fifty Dash Two, creating echoed rhythms from the sounds of a musical saw, electric mixer, en- gine noises, pots and pans. He also extracts mammoth reverberations from plucked piano strings in a three -part suite. David Talcott, way a staff member at radio station KPFA in Berkeley, conducts four experiments using delay loops and the human voice. To be believed, it must be heard, regard- less of the visual attractions present at the ruin time. The stereo effect is contrived without strict adherence to the position of the sounds as originally generated. Listen carefully and your ears will be alerted to some of the stereo tricks engineers can play on ordinary your everyday nwsie. MONOPHONIC valuable Snooks Eaglin: New Orleans Street Singer Folkways FA2476 records? Heard briefly in the first volume of Samuel Charters' "Music of New Orleans," Snooks Eaglin now has an album of his own, through the courtesy of Dr. Harry Oster, of Louisiana State University, who recorded him on home grounds in March, 1958. A minstrel walk- ing the streets of the city today. he be- came blind at the age of two and taught him- self to play a guitar received on his sixth birthday. After revealing that most of his songs were learned from the radio and re- cordings, the notes pose a question as to how many other folk artists obtained sup- posedly "authentic" material in the same way. It is pointed out that these sources, the bane of believers in the oral heritage of songs passed from singer to singer, need not always carry a commercial stigma. True enough in this case, which is no valid test of the theory, ns Eaglin Is a natural blues singer and goes direct to the heart of n song to make it his own. He restores basic emotions and pares away nonessentials. Someone should send him a Ray Charles album. He simulates the traditional solo breaks on High Society. playing without n pick, and his one original is n sriking instrumental blues. Choosing from his vast repertoire, he selects both old and new, proving at twenty - TONEARM CONTROL two that street singers are not a thing of the past. For a field recording, the sound 1s If the tonearm slips out of your fingers and better than usual. bounces over the record -the record is lowers you're you will also Blues In The Mississippi Night the ruined! If unlucky, United Artists UAL4027 need a new stylus and possibly a new Lil Armstrong: Satchmo And Me cartridge. Riverside RLP12 -120 tonearm Why take a chance? DEXTRAFIXO TONE - Two valuable additions to the spoken ARM CONTROL prevents such accidents! It documentation of the music which coursed places the stylus in the lead -in groove - along the Mississippi River in the first part gently and accurately. Then, at the end of this century are made on these recordings. into the Amateur tape recordists should take hope of play or at any point on the record, it on learning that seventeen years have passed lifts the stylus from the record. And the since Alnn Lomax set up his portable disc machine and encouraged three unidentified stylus cannot touch the record until the blues artists to tell their stories. Aside from lead -in lift bar is again lowered for the next play. the primitive sound, about the only point to be regretted is that it took so long to reveal The DEXTRAFIxa TONEARM CONTROL also his interview formula. A model of its kind, facilitates "cueing" at any point on the it places Lomax in the background, inter- rupting the flow of experiences only with groove... record. short musical examples and casual prods A must for turntables -and record from the leader of the group. Although he changers with manual might find a trio willing to speak with equal operation! frankness today, the responses would be dif- ferent and carry less import. Essential to a lifts it study of the blues and Southern folk mords, the text is transcribed in full on an enclosed Another quality product folder and will form part of a book Lomax by the manufacturers of is writing. play! LiI Armstrong's tale of life in Chicago with after LEKTROSTAT® her noted husband during the Twenties de- serves a place besde his autobiography. It Record Cleaning Kit is jam packed with personal memories, from her first meeting the shy youth who was King Oliver's new trumpet player to the final dexte r chemical corp. consumer products div. 845 Edgewater Rd., N.Y. 59

AUDIO AUGUST, 1959 89 breakup of their marriage. Her enthusiasm feeling is also projected on Lover Man, and for the subject is only slightly dampened by a restful Rockin' Chair. an interrogator who seems to have just met The Ramsey Lewis trio, once billed as "The ARE YOU her at the studio. How much more ground Gentle -men of Jazz," steps out in a new would be covered were she allowed to cut guise, distinguished mainly for an improvised up old times with someone like Luis Russell blues lasting five minutes. Here the group's and Buster Bailey ! Lomax shows how to former restraint disappears completely, but SOUND avoid the formality of questions and answers. the controlled teamwork remains. Falling In the next installment, Riverside should put somewhere in between this performance and Louis in a room with Milt Gabler and Joe the soft -sell are tasteful investigations of Glaser. Green8leeves, Dark Eves, and Come Back to HAPPY? Sorrento. Art Blakey: Holiday For Skins, Vol. 1 Humphrey Lyttelton: I Play As I Please To achieve superlative sound reproduction, Blue Note 4004 there must be a reason. Such results cannot London 113101 Hi -Fi Cuban Drums Capitol T10141 be obtained from cheap materials, slipshod Dizzy Reece: Blues In Trinity workmanship, expedient design, or other cost A campaign to educate the populace about Blue Note 4006 cutting devices to make a big, wide profit. drums is continued by Art Blakey, who con- ducts his annual seminar with wonted gusto. Unless employed in the section of a big The Bakers Ultra 12 Loudspeaker and the His elucidators include a septet of Afro- band, most British trumpet players hew close Bradford Patented Baffle reproduce ultimate Cuban percussionists, headed by Sabu and ar- to traditional lines. Those who try to branch facsimile for an inevitable reason. The reason rayed to furnish a background of contrasting out into other styles are apt to find their Is in the specs. rhythms for challenging statements front following falling away and dates hard to find. three jazz drummers. In addition to the Because of his stature as a pioneer in the leader, they are Art Taylor and Philly Joe New Orleans revival, Humphrey Lyttelton BAKERS .tones, whose ceremonial chanting prepares has negotiated the transition to mainstream ULTRA 12 for the bacchannalian rites of The Feast. jazz with fair success, fronting a septet in Atmospheric passages are supplied by Donald his own London Club. Fresh from two- 20 to 25,000 cycles Byrd, trumpet, and Ray Bryant, piano, months of concerts behind Jimmy Rushing, it from a single, ex- while Wendell Marshall is a steadying in- Is steeped in the blues for this session and ponential 12" cone; fluence on bass. The first of two volumes pro- develops three original themes with a vigor in 20 cycle cone reso- duced in an all -night session, it provides an matched by few studio groups this country. Kathleen Stobart, n blue -eyed blonde lady nance; 18,000 gauss; exciting sequel to last year's "Orgy in Rhythm." which will be among Blue Note's on tenor sax, is guest soloist on Johnny 200,000 maxwells; initial stereo releases. This latest Installment Hodges' Going Out the Back 1Van. For one plastic foam sur- should follow shortly. set, it is augmented to thirteen pieces by round; aluminum Blakey is interested in telling a story and Don Rendell's group featuring Ronnie Ross. voice coil on alumi- takes his material from a number of sources, A Paseo band. outfitted with marimba, num former; heavy drawing greatly on the three years he spent bongos and timbales for the Spanish tinge aluminum Ill Africa. He will find his language spoken on La Paloma. almost finds the leader re- east his Hot Five frame; 20 watts; no distortional crossovers. by the corps of drummers assembled in Ha- turning to period. vana, where they were recorded for Capitol Dizzy Reece, on arriving in 1948 from For these reasons, the Bakers Ultra 12 Is by Ramon S. Sahat. Some were brought in Kingston, Jamaica, started from scratch and extremely sensitive, and therefore provides a from the hills to demonstrate the wild now enjoys considerable respect among the smoothness, clarity and transient response... rhythms of native dances. before ballroom home guard and visiting American musicians a true naturalness... not found in any other polish was applied. Assorted gourds are as a modern stylist. When engagements were speaker regardless of Pride of posses- struck, scraped and shaken, along with vari- slim, he would slip over to the Continent and price. ous implements. won many fans in Paris. where this re- sion is only 85 bucks. discarded agricultural The deep bass sounds come from the marimboola, cording was made last year. As the title im- made of metal straps cut from the main- plies. it is most notable for his warm ex- BRADFORD springs of broken, hand -wound phonographs. position of original blues themes. His work And you can't hardly get those kind any- is remarkably free from traces of other more! trumpet men. possibly because he learned a PATENTED BAFFLE great deal from an association with Don Stereo, or monaural, the trend is toward Byes, the expatriate tenor sexist with whom compactness; 12" x 12" x 9" for 85 and 10s; Al Hirt: Swingin' Dixie he traveled about Europe. Two tourists, 17" x 17" x 14" for 125 and 155. Because of Audio Fidelity AFLP1878 Donald Byrd and Art Taylor, join in, and the patented (No. 2,884,423) pressure relief Tubby Hayes makes an eloquent tenor -sax It forced to trim his rampant lines to fit solo of valve, this enclosure is equivalent in results hand be Round About . arrangements, Al Hirt would a car- Both leaders score one point over tra- to a 20 cubit foot bon copy of Harry James. As it is, he com- ditionalist compatriots whose best efforts Infinite baffle. bines the swing trumpet style with the belie brashness of a Wild Bill Davidson, resulting always the place of origin. In their The Bradford case, it is almost impossible to tell. Patented Baffle in n fiery and unquenchable combustion. Not a thought in a carload, apparently. and this provides the only is the way many individuals prefer their Hampton Hawes: Four! true acoustic sus- Dixieland. Hal Cooper, his clarinetist, is Contemporary C3553 pension principle known from early Dukes of Dixieland record- Roy Haynes: We Three New Jazz 8210 for the pressure ings. Bob Havens, trombone. and Paul Ed- relief valve auto- wards, drums. played in the band of the Technique, as applied to a jazz pianist, is matically regu- late George Girard. Bob Coquille, bass, and a word to be weighed carefully in the bal- Ronnie Dupont, piano, are simply natives of ance, an axiom well illustrated in the careers lates the acoustic of Hampton Hawes and Phineas Newborn. or New Orleans. tension spring Hirt's recent departure from the Crescent The son of a preacher, Hawes grew up on of the air within City for the rarified atmosphere of the church music and the blues, first broadening the enclosure to Palmer House is commemorated on Chicano. his style to include Charlie Parker's con- the excursion characteristics of the Bakers, The dozen tunes on his second album are ception of time. Since then, a slow process or any other, speaker. Because of this pat- all tried anti true, from Darktown Strutter's of absorbing ideas and new material was ented principle, there is absolutely no boom, Ball to Song of the Wanderer. Included is guided by his aversion to "technique that cabinet resonance or listening fatigue. Harry James' Feet Draggin' Blues, and a sounds like technique." But there was always robust Battle Hymn of the Republic. enough for what he wanted to say, especially The Bradford Patented Baffle is recom- on his blues originals, one of which is fea- mended by renowned audio authorities, and tured here. Topping a set of standards is sold throughout the world because of its out- Ray Bryant: Alone With The Blues Parker's Yardbird Suite. Mitchell records standing merit and adherence to claims. New Jazz 8213 his first bowed bass solo on Bow Jest, abetted Lewis: Down To Earth by Barney Kessel, guitar, and drummer Mahogany, walnut and unfinished birch; Ramsey Shelly Manne. selected, grain- matched, a/a" plywood veneer; Mercury MG36150 Newborn's debut drew acclaim for the bril- rugged construction; hot lacquer finish . . No jazz pianist worthy of the name can lance of his playing, and he has suffered from hand -rubbed. $34.50 to 809.50. neglect the blues, although record executives it ever since. The need to live up to his usually feel no such obligation. Given the notices has hindered his growth, although Speakers and baffles sold separately. In some these units to be opportunity to express himself at will and mentioned his lack of maturity. Now, combination, we guaranty reaches in an effort to play less and say more, he superior in true realism to any other system unaccompanied, Ray Bryant back to basic principles on five striking originals. assumes a secondary billing to Roy Haynes, regardless of price. Organized in a variety of shades and colors, a drummer who spent backing they incorporate the plaint of early blues Sarah Vaughn. The pianist comes to grips write for literature singers, the spiritual release of gospel song, with blues on After Hours, where his soul - and the glad, swinging approach of the stride searching choruses make this his most in- BRADFORD AUDIO CORP. pianists. Bryant started as a bass player and teresting LP. He includes two Ray Bryant his left hand is strongly developed. He uses tunes, and one original. With Paul Cham- 27 East 38th St., New York 16. N. Y. it in a distinctive manner that avoids the bers on bass. Haynes lends encouragement or Telephone: OXford 7 -0523 limitations of period or style. The blues trims sails to suit prevailing winds.

90 AUDIO AUGUST, 1959 Barney Kessel: Some Like It Hot Contemporary M3565 As the only new tune in this album bears the film title, Barney Kessel needs little prompting from the score to revisit pro- hibition days. Both he and Shelly Manne helped record the sound track, however, and Underside of superstructure. the perils thrust on Pearl White must seem mild after a vision of two Chicago musicians harried by gangsters and Marilyn Monroe. Out of sympathy, they are impelled to adopt the free and easy manner of the Windy City GRAY hysteresis belt drive and blow modern breezes through old fa- vorites. Manne pummels a suitcase a la Josh Billings, while Kessel switches to unampli- fled guitar on Sweet Sue. Joe Gordon, a former Gillespie trumpet man, finds cadenzas missed by Clyde McCoy on Sugar Blues. Be- sides playing alto and tenor sax, Art Pepper explores the lower register of the clarinet on I Wanne Be Loved By You. Pianist Jimmy Bowles and bassist Monty Budwig strengthen the septet's allout choruses on By the Beau- tiful Sea, and Rennin' Wild. Kessel has the added support of Jack Mar- shall on rhythm guitar, and they combine in duets on Stairway to the Stare, and I'm Thru With Love. There is enough of a hint of what to anticipate in stereo here to ad- vise waiting for it. On two numbers, Kessel uses a bass guitar, with a range as deep as a bass violin, and believes this to be the first time it was recorded as n solo voice. An interesting sound, and the way his deft fingers keep it from conflicting with the bass is another reason for his top rating as a guitarist.

Theodore Bikel and Geula Gill: Folk Songs From Just About Everywhere Elektra 161 William Clauson: Clauson In Mexico! Capitol T10205 Where folk singers once remained close to their national heritage, the modern profes- sional is becoming more and more a cos- mopolite. Tours embracing several foreign lands make it impossible for concert artists to resist adding to their repertoire, and those staying at home follow their example by means of recordings. Since leaving her native Israel, Geula Gill traveled in South America and Theodore Bikel has been just about every- where else. They unite in the songs of eleven GRAY turntables offer you more nations, sung in ten languages other than for English. As might be expected, they are most your money by incorporating engineer- comfortable with Hebrew music and tend to select material of a similar nature, no ing features guaranteeing that what matter what the origin. Dov Seltzer and Fred Hellerman helped plan trips to Bolivia, you buy today will give you top per- Roumania, Brazil, Persia and Argentina, formance many years from now. while Billy Paler assists on banjo. Oversized girder- constructed William Clauson's first album was re- platter corded in New Zealand in English, and his and shaft. second in Stockholm in Swedish, Norwegian An important factor in GRAY'S 'time- and Danish. When at home, the big, blond Swedish -American lives in California, rela- tested' construction is the exclusive stretch - tively close to the source of the dozen songs which take him south of the Rio Grande to belt. The GRAY stretch -belt establishes an a studio in Mexico City. He sings them in accurate Spanish with El Mariachi Mexico, giving the running balance between the hys- willing little band of mariachis a cheerful teresis- synchronous motor and the oversized guitar lead. He prefers a livelier beat than is usual, imparting a new zest to Veracruz, platter and bearing assembly without tedious Guadata jara, and .ifalaguetia. GRAY 33H 'Custom Deluxe' turntable $79.95 spring adjustment. There's never any prob- (Shown with 212 -SX 12" tone arm, $34.00 and 33C wood base, $23.95) Djamal Asian: Lebanon 20th Fox 3001 lem about replacing worn parts because An Evening In Beirut Capitol T10189 GRAY record playing equipment is designed After being introduced to the seductive and constructed to run maximum music of the Middle East by Mohammed El- at effi- Bakkar, those adventurous souls whose ap- ciency practically forever. petite for strange sounds remains unappeased will welcome the opportunity for further indulgence. An accomplished oudist, Djamal Asian is gifted with a romantic voice which transcends language barriers. As a composer, he shows a knowledge of Western rhythms, sometimes incorporating them in tunes meant GRAY HSK-33 Turntable Kit $49.50 for the younger set. And his six years at the (Shown with SAK -12 12" tone arm kit, Conservatory of Music of the University of $23.95 and TBA base, $17.95) Cairo enables him to give an authentic pulse GRAY to the singing and handclapping of a twenty - seven voice chorus under Edouard Ghazal. Since arriving on these shores, he has ap- High Fidelity Division peared in concert at the Library of Con - (Continued on page 104) DEPT. 6 16 ARBOR STREET, HARTFORD 1, CONN.

AUDIO AUGUST, 1959 91 BEYOND COMPARE RECORD REVUE

Needed -A Listening Room!

Sewanee, Tennessee white. Live as all get -out but not as live as I'YE DONE ]MY BEST -bUt I just couldn't my earlier concrete class room nightmare. review any records for you this month. I spent two days in search of rugs. There The reasons are interesting. weren't any. Finally I got into the store If you have read AUDIO, ETC. in this rooms of two college dormitories, closed for issue, you will know what happened upon the summer, and came forth with about six marantz console my arrival here in lovely Tennessee, where floor -rags of the rubber -backed type, in all the temperature ranges around 5 degrees (One of them stank so Consumer Net states of discolor. $249 lower than that of New York City, given badly I had to wash it in the shower room Cabinet heat got 24 a good hot spell. It wasn't the that up.) also snitched higher in West with Cheer,* to cheer it I Slightly me but the liveness. Plug. I brought down with me something like a big green square of the same, clean and In pre -amplifiers and power ampli- 500 LP records, mostly stereo, including all about 10 by 12, from a private bed room, fiers, Marantz has set today's highest the recent ones I could lay a hand on; I took all my car blankets along -and man- standard of quality. toted along two complete stereo systems - aged to dampen down that band room so four speakers-just to be sure I could play is now merely very live. Not vio- Consider the Marantz Stereo Console. that it them. And yet in the first nine days here, I lently live. And I'm playing records again. Here is the essence of uncompli- got to play just one -half a record. if cated, beautiful styling. So simple to Now I understand. What I should have use, even the most non -technical done was bring (a) maybe 20 records and While I'm at it, I'll present some cogent person can easily achieve matchless one "hi -fi" and (b) I should have hired me rules for listening -room acoustics. reproduction quality. Yet, this fine a trailer and filled it up to the brim with 1. The right acoustics (and the right instrument offers an order of versa- every rug, blanket, pillow, mattress and room configuration, for stereo) are more tility that pleases the most discrimi- other sound- deadening device I could lo- important than any other factor in record nating professional users. Carefully cate, plus any extra rolls of cotton batting, listening -more important than all the fi planned circuitry and wiring layout quilting, insulation, and what -not that in the whole chain of sound reproduction. result in unsurpassed freedom from could be commandeered for the occasion. Flout this law at your own risk. distortion, hum and noise. Then, perhaps, I could have furnished 2. There is a fairly wide tolerable area in which we can enjoy recorded sound, to quality in every detail you'all with a few nice, authoritative record Dedication ranging from fairly live to fairly dead is the reason why the Marantz 30- reviews, out of a reconditioned and sound - (with other more complex factors such as watt power amplifier, too, is in a deadened Southern classroom. shape aside for the by itself. The Marantz circuit Nope, (this is written later than AUDIO, room size and put class moment). But beyond this area -much too permits this superb amplifier to re- ETC.) -I didn't get to use that goh'geoua live or much too progresses cover instantaneously from sharp. big fraternity house room, the only avail- dead -listening sound - musical transients to effortlessly able one in this town that has really from difficult to impossible. The drive loudspeakers of all types to proper living room acoustics. Instead, I message simply is not adequately received consistently outperform amplifiers of went around the campus searching for by the brain. considerably higher ratings. something else-and was I amazed. One 3. Stereo reproduction greatly extends place after another I tried -front halls, this range of tolerance in the dead direc- For both stereophonic and mono- lounges, coffee rooms, class rooms, pool tion-indeed, almost to extreme deadness phonic programs, Marantz is your rooms, play rooms, common rooms-and not in the listening acoustics. The deader the assurance of long, carefree operation a single one of them had so much as a room, the greater the audible difference and unprecedented performance. stitch of soft material in them. Seems to be between mono and stereo sound. This is a a policy of the University of the South, major virtue of stereo. which might just have something to do In the direction of too much liveness, with that old Suthunn problem, dampness stereo simply merges with mono sound into and mildew. an unintelligible jumble. What I must point out to you is simply 4. A vital point: within the tolerance that under really poor listening room con- area of listening liveness, we are able to ditions, record listening is just plain im- learn, after long familiarity, to ignore the possible. Even with the fanciest hi -fi equip- listening effect of our own rooms in favor ment on the market. of the objective effect of the recorded I will review you any good LP record at sound. We hear the record; we close our all on a portable table -top "hi -fi ", if you ears to the room. This is a major factor in will give me a good listening room for it. good listening and accounts for our general And I'll stand back of my opinion, against agreement, such as it is, concerning the all comers. But in a bare class room, a qualities of this or that recording. swimming -pool -style lecture hall, you could But -in a new, a strange listening place, 30 -WATT AMPLIFIER not drag me into writing three words about we must begin all over again and re- educate any recording, no matter how superduper our ears to the new sound, before we can Net $147 Grill 7.50 the hi-fi. And so-on principle, I give you hear our records as before. (Note that the Slightly higher ln West no reviews this month. Take a month off, same principle also applies to new reproduc- everybody, for silent contemplation, upon ing equipment, notably the loudspeaker.) * Selected for demonstration at the the importance of the listening room. 5. In a new or unfamiliar listening place, American Natl. Exhibition in Moscow P.S. I have finally found a nice old band those records which compensate for the ex- practice room and fixed it up tolerably well isting conditions will sound best. Thus in -just tolerably. It was entirely bare, as an abnormally live room, your deadest not tile, recordings will sound fine, but the records CO MP A NY usual ; but the floor was of wood, were wallboard, painted with larger built -in liveness will be a 25 -li BROADWAY, LONG ISLAND CITY 6, N. Y. and the walls AUDIO AUGUST, 1959 92 i M E D IRTE D ELI VERY

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AUDIO AUGUST, 1959 93 leading audio magazines say .. . jumble. Similarly, in a dead room your very live recordings will come out on top. But, again, long familiarity with the listening room will tend to cancel out these GRADO effects. FINEST QUALITY Keep this in mind when entertaining friends who don't know your listening room, or in giving lectures and record dem- onstrations in strange places. Suit the rec- AMPLIFIER CAN BE ord to the listening room -in reverse. 6. An excellent objective test for room ... takes pride in announcing liveness is the sound of a close -to recorded speaking voice. In a good room it will a new Custom Series Stereo sound natural, unforced, realistic. In an Cartridge. The Grado "Cus- BY YOU overly -live room, the vocal sound has a ASSEMBLED tom" was designed for the tell -tale hollow, metallic quality (which seems to be in the recording, of course). In selective audiophile who de- a dead room, the recorded voice will seem sires excellent reproduction startingly close to you, the sibilants much IN A fEW HOURS! too distinct, the over -all sound rather bossy. at a moderate cost. With its 7. A final, and to me inexplicable, rule: tracking Acrosound Ultra -Linear Il Amplifier Kits have excellent ability and a. In an ultra -live room, reproduced astounded leading electronic exponents with extremely low distortion, the their ease of construction and high quality per- music seems drastically to lack highs; the new formance. Quick and simple to assemble ... no middle range is pipey, metallic, hollow, the Custom Stereo Cartridge experience necessary. Lowers cost because you bass is hugely exaggerated. (Cf. AUDIO, becomes a perfect compan- do it yourself! Follow the choice of experts - ETC.) enjoy the ultimate in stereo sound, in your b. In an ultra -dead room, oppositely, the ion to the widely acclaimed home now in a matter of hours! highs seem strident and Missy, the bass is Grado "Master" Stereo Car- unimpressive in effect, though present. tridge. Because of small mov- You figure that one out for me. . ing masses and low tracking forces, stylus wear is virtually NEW LITERATURE nonexistent. Grado Labora- tories now guarantees all of Valor Instrumenta, Inc., 13214 Crenshaw Blvd., Gardena, Calif., will mail free a 4- the stereo diamond stylii for ACROSOUND ULTRA -LINEAR II $7950 page pamphlet which discusses the max- imum dissipation in transistors. a period of 5 years from date AMPLIFIER power KIT e7 Methods of determining the maximum of manufacture. power which may be dissipated by a tran- rated continuous output of 60 watts sistor and the effects of maximum power A greatly improved Grado "With an of less than 1 per dissipation on power at an IM distortion quality circuit considerations are illustrated. Factors to consider in arriving Tone Arm is now available. It _cent, constructiontfoperration an allowable collector such Thesentire two hours by the most at dissipation require more than as thermal runaway are also explained. is dynamically balanced and is inexperienced." 1958 -AUDIO This an excellent treatise for the audio features a new micrometer December design engineer. 8-1 Electro- Voice, Lao., Buchanan, Mich., has tracking force adjustment. "As Just released Catalog 120A, a descriptive a result of careful predesign Stylus force accuracy of the U planning, new guide to Electro-Voice -Ill goes together in something professional two hours. It represents under microphones. This complete con- tenths grams may now be a superb blend catalog of constructional ease and of tains the photograph, response curve, polar guaranteed superior performance, to delight the most hard pattern, wiring diagram, dimensions, and achieved with complete sim- fanatic and the -to- please listener." most dedicated music complete specifications for each micro- phone. A copy of this informative booklet plicity. Also new is a stainless HIGH FIDELITY MAGAZINE should join the technical library of every steel arm rest lock. All present December 1958 broadcast station, motion picture studio, and recording studio in the country. It Grado Tone Arms can be will be mailed upon written request, or may be obtained from E -V distributors. modified. extremely simple since a "The construction is circuit K -a board of basically the entire printed left to the con- is furnished. All that is really Unimaz Switch Division, The W. L. Max- wiring of both the transform- structor is the the front on Corporation, Ives Road, Wallingford, Master Stereo Cartridge . . . 549.50 ers kit that Conn., presents detailed information on the panel. Athnew o60 -watmountedamplifier Custom Stereo Cartridge . . 532.50 feedback circuit with ex- expanded line of Unimax snap- action pre- employs an unusual Stereo Tone Arm 529.95 stability ... The total time required cision switches in its new 28 -page Catalog Micrometer ceptional 21h hours." build the kit is approximately No. 359. Convenient pictorial index shows to where to find dimensional drawings, de- RADIO TV NEWS scriptions, force and movement specifica- It tion tables, and electrical ratings for each Unimax switch listed. Data on bases, ter- "The steps are few and the booklet minals, circuit arrangements, and NEMA companying pictorial and ac- are clear and easy to standard definitions of sensitive switch follow . Test results . In the last and terms are also included. Requests for most important test, the amplifier clean and sounded copies should be directed to the attention performed beautifully at all volume levels." of Mr. J. Martinez. H -3 For further details write to: POPULAR ELECTRONICS Ohmite Manufacturing Company, 8630 March 1959 Howard St., Skokie, Ill., has done the elec- tronics industry a distinct favor with the GRADO LABORATORIES, INC. publication of its new Catalog No. 30. Corn - Write today for FREE descriptive litera- plete in every respect, well planned and 4614 7th Avenue Brooklyn 20, New York printed, this catalog should be in ture on all Acrosound Amplifier Kits. clearly 25 St., N.Y.C. the hands of every person engaged in the ExportSimontrice, warren purchase of electronic gear on a profes- ACRO PRODUCTS COMPANY sional scale. Design and production engi- 369 Shurs Lane, Phila. 28, Pa. neers alike will find this comprehensive listing of Ohmite products to be of great ACRO ... THE FIRST NAME IN AUDIO value in their work. Available on written 94B Circle 94A request. 8-4 Circle

1959 94 AUDIO AUGUST, TAPE GUIDE (from page -fu) l restoration will be complete. Therefore it is all the more desirable in this situa- tion that the tape recorder be capable of being driven by a signal well below 0.5 volts. The sensitivity required for micro- phones depends a great deal on the type of microphone used. Of the two types most apt to be used by the home record- i ist- piezoelectric and magnetic micro- phones -the latter generally produce considerably less signal. At ordinary HOW speaking levels a few feet distant, the magnetic microphone may produce about 2 or 3 millivolts at average levels and DID perhaps 10 to 15 millivolts on peaks. Al- lowing for a reasonable reserve of gain, an input sensitivity of about 2 millivolts is desirable. PU Output Level If the tape machine (that is, the sig- HIGHER nal from the tape amplifier) is played back through a high -fidelity system, most often it will be fed to the control ampli- FIDELITY fier, which generally can he driven to the desired level (enough to drive the INTO power amplifier and speaker in turn) by signals of about 0.1 to 0.5 volts, depend- ing upon the particular control ampli- THE fier. Allowing for a reasonable reserve, it may be said that an output of 1 volt HARTLEY from the tape machine should be suffi- cient in virtually all situations. One volt should also be enough to drive a power CAPRI ? amplifier directly, as is sometimes done, because most power amplifiers can be driven to full or very high output by 1 volt or less. *it's polymerized. (If the playback signal is taken di- rectly from the tape head, then one must The all new Hartley Capri ... the FIRST and ONLY shelf speaker Hartley's famous POLYMERIZED system with look to cone ... combines a newly engineered Hartley - the control amplifier rather than Luth Speaker with revolutionary POLYMER to the CHEMISTRY to provide a high tape machine to assure there is fidelity "break through" that you can actually HEAR. Your music achieves sufficient gain. optimum fidelity -free of fuzziness and cone "break up" caused On signal peaks at 1000 paper cones. by conventional cps, the tape head will produce roughly The Polymerized cone makes the Capri virtually "weather- proof" the first 5 millivolts or less on a half -track shelf speaker that gives year -round quality performance ... tape; extreme humidity -even under the most and correspondingly less or temperature changes. on a quarter - Capri cabinetry matches its advanced electronic track tape. Thus for design. It is decorator styled at 1000 cycles the con- shelf or console use (24" x 131" x 12 "), and rigidly constructed of solid trol amplifier should be capable of being %" oil -finished walnut. Its exclusive all- bamboo grille with special acoustical weave liberates every note undistorted. Only the Hartley driven to about 1 volt for a acoustic Capri utilizes 85' of signal of material to permit pure response down to 30 cps. All these exclusive about 2 millivolts from a tape head.) features combine to give you truly higher fidelity response. Audition this handsome compact speaker at your franchised Hartley Dealer today. Hear Adjustment Facilities for yourself how chemists put higher fidelity into the new Hartley Capri, only 3120.00 - Every tape recorder should have Fully guaranteed for five years. means for readily adjusting the azimuth Write for complete FREE information and of the specifications on the entire House of Hartley heads, so that the gaps are per- line of stereophonic and monophonic speakers pendicular to the length of the tape. and enclosures, and the name and address of your nearest Hartley Franchised This is commonly achieved by locating a Dealer. spring under one or more of the head mounting screws, so that tightening or loosening the screws slightly will tilt the head about its vertical axis. products company Adjustments for equalization, bias artley Dept. A -8, current, and calibration of the record - 521 East 162nd St., New York 51, N. Y. level meter are seldom found in machines "Over 25 years of Electronic Development for Better Listening." of the home type, but are generally Export: Teltech in- International Corp., 431 5th Ave., New York 16, N. Y.

AUDIO AUGUST, 1959 95 corporated in the better grade machines or most playback heads used today have hack equalization is adjusted to conform associated with semi -professional and gaps sufficiently fine so that treble losses to the standard curve, then equalization professional use. If a tape recorder is at 7.5 ips and higher speeds are negligi- of the record amplifier-in particular, to be capable of consistently providing ble. On the other hand, as a playback treble boost- should be capable of ad- high -grade performance, then the fol- head wears, its gap tends to widen and justment to yield relatively fiat response lowing adjustments should he available. treble response to deteriorate. Thus an on a record- playback basis. Some ma- 1. Playback Equalization. At 15 and adjustment for frequency response at chines incorporate two adjustments; one 7.5 ips (and perhaps at 3.75 ips as well), the very high end-above 10,000 cps or determines the maximum amount of equalization of the playback amplifier so-can prove useful. However,. such treble boost, and the other the point at should conform to the standard curve, equalization has limits. For one thing, which treble boost commences. This per- which is NARTB at present. Equaliza- after the gap widens to a certain extent, mits very accurate shaping of the re- tion can be checked and adjusted on the the drop in high -frequency response be- cording characteristic. basis of a series of frequencies fed into comes too sharp to compensate satisfac- 3. Bias Current. As pointed out ear- the amplifier from an audio oscillator or torily. For another, excessive high -fre- lier, the amount of bias current fed to by playing a test tape. Some tape ma -' quency boost in playback accentuates the record head governs the amount of chines include compensation for treble noise of the playback amplifier. recorded distortion. Up to a point, an losses due to the playback head. Many 2. Record Equalization. Once play- increase in bias reduces distortion. Be- fore this point is reached, however, bias current causes severe high- frequency losses in recording. At 15 ips, one can usually adjust bias for minimum dis- A NEW STANDARD OF VALUE tortion-without seriously affecting treble response, because the high -frequency losses become very severe above the IN HIGH FIDELITY audio range. But at 7.5 ips and lower speeds, these losses are severe within the audio range. Therefore at 7.5 ips and SPEAKER SYSTEMS lower speeds, the bias setting is critical, being less than that which produces mini- mum distortion. One must make sacri- fices both in distortion and in frequency The ME -12 response, and the problem is to find the optimum amount of bias that does not Speaker System unduly sacrifice one performance charac- for Stereo or teristic for the sake of the other. There- Monophonic Use fore the ability to adjust bias to the optimum level is important for the per- son desiring the best possible results. A $99.50 previous article pointed out that tape machines which use a meter as a record - level indicator generally employ a switching arrangement so that the meter can be used to check whether bias is correct. Inasmuch as the proper amount of bias current will vary with tape speed, and even with brand or type of tape, it is desirable that the bias control be fairly accessible. Setting the Pace in Quality, Integrity, Value 4. Record -Level Indicator Calibration. A high -quality machine will permit one Out of the laboratory comes a truly remarkable new Speaker System that defies comparison in quality performance at a low price. The to adjust the amount of signal fed to the AUDIO -TECH ME -12 easily outperforms units twice its size and price. record -level indicator so that it accu- Designed by Joseph Giovanelli to meet the exacting requirements of rately indicates when the amount of reproduction, the ME-1 2 produces startling stereo and monophonic sound tape produces a given results. Just read the features below: signal fed to the amount of distortion -2% or 3% har- Entire system possesses superior transient response 40 to 20,000 cps full load input capacity -30 watts 12" extra- heavy -duty woofer with monic distortion usually being consid- 2" voice coil -permanent magnet (32 oz.), 12,500 Gauss High quality ered the maximum permissible amount. 3" cone tweeter tweeter balance control with calibrated scale for accurate resetting fused to prevent overload laboratory pre- tested Bias Frequency and inspected. to discernible heats be- CABINET: Infinite baffle sloped front hand rubbed oil finish in natural In order avoid walnut, mahogany, or fruitwood 24" h. x 12" d. x 14" w. tween the bias frequency and harmonics frequencies, the bias fre- 2 -YEAR GUARANTEE AGAINST DEFECTIVE MATERIALS AND /OR WORK- of the audio MANSHIP. quency should be about four to five times the highest audio frequency, namely be- tween 60,000 and 75,000 cps. While 75,000 cps or higher is even more de- Laboratories sirable, a limit is set by the fact that ch capacitive losses in the record and erase heads increase with frequency. Accord- Department A, 3420 Newkirk Ave., Brooklyn 3, N. Y. INgersoll 9 -7134 ingly, the bias oscillator has to work

AUDIO AUGUST, 1959 96 proportionately harder as bias frequency increases, which raises the problem of distortion in the bias waveform and at- tendant noise. Hence 75,000 cps or so is a practical. maximum for the bias fre- quency. A frequency much below 60,000 cps is open to serious question as to its compatibility with high -fidelity per- formance.

A -B Switching In a machine having separate record and playback heads, it is highly desirable that there be an A -B switching facility, as illustrated in Fig. 17, to permit com- parison between the incoming signal and the signal recorded on the tape. Specifi- cally, the output jack of the tape ma- TD -124 $99.75 net chine and the monitor jack should be switched between the incoming signal and the playback signal. Comparison be- tween the two signals can then he made WHAT MAKES by earphones connected to the monitor THE TD's jack or by means of a sound system fed from the output jack.

Record Interlock One of the catastrophes that occasion- ally befalls the tape recordist is that of STO inadvertently erasing part or all of a PS? valued tape because the machine is ac- ...finer for stereo...finer cidentally set in the record instead of for mono playback mode. To minimize this danger, If you move in circles where component most tape machines provide a safety in- after you've placed stylus, permits 2/3 terlock that prevents putting the ma- hi -fi is a by -word, you've no doubt heard rev. starts, makes cueing easy). Ex- about the Thorens TD -124 chine into record position unless one transcription tremely low rumble (mirror -finish main - simultaneously actuates a special record turntable and its fabulous performance. bearing, nylon- seated ball -thrust -bearing But for late-corners button or lever. This button or lever we'd like to point up reduce both vertical and horizontal rum - should automatically disengage when the just a few of the really big features (non- ble to a new low, so important for stereo). machine is put into any other mode of technical readers may skip remarks in 2 -way motor rumble reduction (both operation. To further minimize the dan- parentheses): Extra heavy table for con- an extra -large idler and an ultra- compli- ger of accidental erasure, some tape re- stant speed (10 lb rim -concentrated table ant belt -drive keep motor vibration and corders have a warning light that goes insures low wow and flutter; higher mo- speed variations from table). Driving on when the machine is in the record ment of inertia than any similar table). parts electronically balanced. No costly mode. Exact speed ( +3% adjustment on all base necessary (only $9.00). 50/60 cy- speeds -162/3, 331/3, 45, 78 -with built - cles, 100/250 volt operation. Automatic Equalization Change in illuminated strobe for setting after These are just a few of the TD -124's stylus is on record). Easy on records features. Ask your dealer to tell you the It is desirable that the record equali- (unique two-table design permits starts whole story zation, and if necessary the playback on the fabulous TD -124. equalization, be automatically changed Now two budget-priced when going from one tape speed to an- TD turntables other. These 4 -speed turntables have same basic Number of Motors adjustable -speed precision -drive as famous TD-134 TD -124 but you save two ways: (1) they come The transport has three basic me- $60.00 net already equipped with stereo -wired professional chanical functions so far as the record arm without overhang making them ideal and playback modes are concerned: (1) changer replacements. (2) Some TD features have been eliminated to save you money. But they still top the performance RECORD of every similar HEAD turntable and player on the market. TO-184 has semi -automatic operation. TD -134 is man. INPUT RECORD o - ually operated. Precision metal stroboscope AMPLIFIER TD-184 (50/60 cycles) furnished with each $75.00 net unit. 100/250 volt operation. Wooden base only $6.00. PLAYBACK o OUTPUT *Mks HEAD JACK Write Dept. A -8 for catalog on complete Thorens Hi -Fi line PLAYBACK AMPLIFIER SWISS MADE PRODUCTS A -B SWITCH MONITOR HI -Fl COMPONENTS LIGHTERS JACK SPRING- POWERED SHAVERS MUSIC BOXES Fig. 17. A -B switching arrangement. NEW HYDE PARK, NEW YORK

AUDIO AUGUST, 1959 97 To turn the takeup reel in a given di- Tape Handling in about 60 to 90 seconds; semi-profes- sional and professional units require as rection; (2) to cause the supply reel to The speed, ease, and smoothness of little 30 Smoothness of wind- tend to turn in the opposite direction so tape handling are among the factors to as seconds. ing is of greater importance than speed, as to provide back tension on the tape; be considered in acquiring a tape re- one should not be overly (3) to drive the capstan, which in con- corder. Starts and stops should be fast, however, so distressed about a slow- winding machine junction with the pressure roller grips but accomplished with sufficient smooth- the tape and pays it out at a prescribed provided that it winds uniformly. The ness to avoid breaking or stretching the rate of speed. As a general rule, the slower the winding speed, the less the While some professional machines best performance -most accurate speed tape. tendency to stretch the tape or generate come up to operating speed or to and least wow and flutter -is achieved can stresses that can result in distortion. by transports having a separate motor a full stop in as little as 0.1 second, as Some tape recordists, where utmost for each function. On the other hand,, much as 1 second is usually adequate for quality is sought, have been known to there are a few single -motor transports home purposes. rewind a tape at operating speed by that through excellent design and con- A transport should be able to wind a reversing the reels and putting the ma- struction achieve results about as good. 1200 -foot reel of tape in either direction chine in the playback mode. If the wind- ing speed varies according to the tape speed setting (7.5 ips, 3.75 ips, etc.), it may be advisable to rewind the tape in the slowest available speed.

Tape Lift To minimize head wear, which is due to abrasive action of the tape against the heads, it is desirable that the tape be automatically spaced away from the heads during rapid wind or rewind. In some machines, this spacing is deliber- ately kept small to permit a slight amount of signal pickup (chiefly low for the /1 man in 7 frequencies) to facilitate locating a de- sired passage on the tape. who can ` separate Loading the wheat from the chaff Loading of the tape machine should be a simple, rapid procedure, without u H E 2 u NI v E R SA the tape having to be threaded through a complex system of guides, rollers, and so on. Most transports today feature SELLS FOR "in- line" loading, where the tape is merely dropped in a straight or slightly curved slot and thereby properly en- $29995 mechanism, heads, and plus Fed. Ezc. Ta. gages the driving so on. There are times when the operator AUDIO Complete will have to reload as rapidly as possible ACTIVATED UHER UNIVERSAL -for example, when taping a program with off the air -and facile loading can then AUTOMATIC Remote Control be a most important asset of a tape Microphone. CONTINUOUS Carrying Case, machine. The purchaser will want to check that PLAYBACK Empty Reel and Dust Cover the tape path is such as not to skew the tape, but allow it to wind from one reel RECORDER onto the other without scraping the top TAPE or bottom of either reel (assuming the reels are not warped). If the path causes SLIDE PROJECTOR SYNCHRONIZED AUTOMATIC the tape to skew, not only is there a scrapes the MODULATION CONTROLS TRANSISTOR MIXER - takes 4 different signals simultaneously disturbing noise as the tape reel, but the azimuth relationship be- 7 Push Button JAM PROOF Keyboard Self- contained SPEAKER SYSTEM and TAPE DECK Operation tween the tape and heads may be af- REMOTE CONTROL DYNAMIC MICROPHONE 5 INPUTS 3 TAPE SPEEDS from 15/16" fected.

HYSTERESIS SYNCHRONOUS MOTOR SEPARATE RECORDING AND PLAYBACK VOLUME CONTROLS Tape Index UP TO 8 HOURS RECORDING TIME AUTOMATIC REWIND AUTOMATIC COUNTER - to find To facilitate location of a passage on de- your place in seconds 40.16,000 CPS, Sig. to Noise Ratio 45 dbs, Wow and Flutter + or - .3% a tape, a tape index of some sort is sirable. Most transports at least provide WORKS ON ANY POWER SUPPLY ANYWHERE CONVERTIBLE - at the flick of a button - for markings under the reel to indicate MUSIC, for DICTATION. Precision Engineered by Craftsmen of West Germany elapsed time or remaining time at a where the tape recorder originated given speed. In addition, a number in- For Your Nearest Franchised Dealer, Write corporate a mechanical counter of one type or another. Some employ a clock - WARREN WEISS, sole U. S. Agent, c/o TRANS -WORLD ELECTRONICS, Inc. type dial and revolving hand. Others Dept. A 1650 Broadway, New York 19. New York use rotating numbered discs.

98 AUDIO AUGUST, 1959 Editing Facilities The serious recordist may be con- 044,d. 4L4A cerned with editing problems, where it is S.,1:1-Pi...... ,.z r necessary to make splices at a given note _ or syllable. In this case, it is important re' to the recordist that the machine provide easy access to the tape when it is in front of the heads, so that he can mark the exact point on the tape where a splice is to be made. Controls Push -button controls- either mechani- cal or employing solenoids -are found in many tape recorders, both of the home ir!rti type and of professional grade. While they offer operating convenience com- 11 pared with transports manually actuated '[.(L.rfKKp by levers, on the other hand the more (/' complex the mechanism the greater is ism the possibility of malfunction. Moreover, Ua-a,- Otite," there is less "feel" to a machine with &la:44 z.g push- button control, and tape breakage fl

or spillage may occur if the push- button .. mechanism functions improperly. Æ ;14, Mad; .lebee"if,14! 14 drG1^-

C-/.4'F . BOOK REVIEW Q.ri . :.._ -... The Audio Cyclopedia, by Howard M. Tremaine. 1280 pages, 6" x 9 ", 354 half- a..4.4.ae tone illustrations, 1300 line drawings. e 4e,;(4!t , ty 74. mid , .. Indianapolis: Howard W. Sams & Co. $19.95. The first complete audio handbook has 4,41,-et finally made its appearance. Said to have he;ii been eight years in preparation -which we can well believe -and two years of editing, The Audio Cyclopedia brings more /t_J. C 7- than a wealth of information between JL its . covers. Its 26 sections begin with the ` basic principles of sound and continue fr ce," through acoustics, constant speed devices, 4, Ct/tte .. components used in studio -type systems, amplifiers, disc recording and reproduc- a ing, magnetic and optical recording, mo- ( f'L ... tion picture projection equipment, loud- ht/s&-1-,66 speakers, power supplies, test equipment, measurements, installation techniques, and general information. The obviously added -on last chapter, about disc w4 .,...,..«..-..'" stereo, is the only one not fully up to date. The book is presented as a series of ` questions, with the text comprising the atettr°veerkeeed, a ZAtl. answers to them. This makes for an un- usual style, but it appears to be as effec- ,t tive as the more common style, and at least more informal and therefore f / more tl.F e4,14# ofÿt readable. a' / Some 240 pages are devoted to test a'` f,./ f equipment and audio measurements - y-it teatfG'V / l!4` / y K sections which in themselves would make 1` á.oir` a valuable and much -needed book if they were available alone. About 170 pages cover optical film recording and motion (t`ì, it: '` ! picture projection equipment - rather ``1 more than seems necessary since a rela- tively small number of people actually work at it. However, much of the basic "DM audio engineering came from the motion f34.5) picture studios, and the author has been in that line of work for most of the thirty . , years that this reviewer has known him. :;frrLIG /et, Practically every subject we have looked up has been covered in this cyclopedia - which is more than can usually be said ,/^. about most cyclopedia -and on those sub- NEW 11411 AI y EC7`PO;f IC y ",. I jects with which we are familiar it ap- pears that the information is adequate, /Ued-4,44-u,z.;;Iy correct, and well presented. We know of . _¡ /l no other single source of so much audio L;12tZ9 G VGktdols! information. -CGMcP !/- f7 AUDIO AUGUST, 1959 99 HAROLD LAWRENCE Lofty Music in Paris

To the crew about to undertake a record- sor, Charles -Marie Widor, held the post for ing of the St. Sulpice crgan, the most for- no less than 64 years and, quite naturally, midable impression made by this sprawl- the little room is a tribute to his memory: ing 18th century church is that of stairs. there is an oil portrait of the late master Stairs in front of the center portals, spiral as well as other memorabilia including his stairs winding up toward the organ loft, desk, furniture, and manuscripts. In its perilously narrow wooden stairs going to simplicity and lonely setting it has a the platform above the mightly instru- strangely moving effect on the observer. ment, and more stairs to the uppermost Above the organ loft, through another ramp of the interior of the church. The longest continuous stairway is the spiral locked door, we reached as far as stairs one; taken at too fast a clip, this cork- could bring us, namely, to the upper ramp screw -like ascent can set your head spin- of the interior. After looking over the ar- ning by the time you reach the landing, ray of pewter -toned pipes from our van- and, if the steep climb does not make you tage point, we calculated what the most dizzy, the view from the balcony down the practical microphone position would be; full length of the church (some 400 feet) then we examined the walls of the church will do the job. From here, powerful Dela- to locate a good rope -tying spot. (The rail- croix frescoes look down upon noble col- ing along the ramp is precariously shaky.) umns bathed in a topaz-,colored light (the Much to our delight, the 18th- century archi- temporary yellow stained -glass windows tects had thoughtfully included a pair of are replacements for wartime casualties). built -in iron rings in the walls on both The beauty of the proportions of the in- sides of the organ. We therefore strung terior conveys a sense of repose and bal- our rope and pulleys through the rings. ance that is in marked contrast to the "ex- Now that we had decided on an over-all uberant decorative art of the lateral chap- microphone setup, the next plan of action els, with their globe "clouds," cherubs, was to locate the monitor room. This and concealed lighting. There is even a.. proved to be a more difficult undertaking. pair of gigantic Venetian shells in the In terms of access to the console, there aisles which are used as holy water vessels. was, of course, the organist's study behind All these stairs are located in the south the organ loft; but this was rejected be- tower of the church, the focal point of the cause of the size: it was large enough to preparatory work involved in the record- accommodate the three speakers, all right, ing. In the manner of an army about to but no personnel. The sacristan then sug- storm the heights of a medieval fortress, gested the ground floor chapel of the south the first order of the day was to explore tower which is in use only once a week. the tower from ground to turret in order But that would have made it necessary for to discover the most convenient and short- M. Dupré to climb the equivalent of seven est route for the audio cables. This, of stories in order to go from console to moni- course, was dictated by the placement of tor room each time he wanted to hear a the microphones and the disposition of the playback. At this point, Minard recalled playback room. Our guide for the investi- that there was a chapel (now abandoned) gation, M. Minard, the sacristan, brought not far from the organ loft, on a slightly with him a large batch of keys with which higher level. Up we went again. Opening to open the numerous doors, gates and par- a door behind the organ pipes, we ascended D41 titions as we proceeded mole -like through a narrow wooden staircase, pushed open a the dimly -lit passageways. Illumination was trap door, climbed a few stairs, and there provided by means of a series of buttons we were. Nothing remained of the chapel found at regular intervals along the way. except a statue of the Madonna. The rest By pressing one of these, electric bulbs of the long room contained chunks of light up throughout the tower. An auto- crumbling masonry, an oil canvas lying matic timing device turns off all the lights beneath a pile of broken straw chairs, every minute or so, however, and you are several empty beer bottles, and some 1937 then thrown into a dungeon -black darkness. newspapers. Apparently the chapel had A stranger in the tower, not knowing where been used as a recreation room for con- the next light button was located, would struction workers during a period of have to grope forward cautiously, and church repairs. We learned later that stu- search along the walls with his hands for dents' mass was celebrated here many the button. At moments like these, it was years ago. When we told Dupré that we reassuring to have Minard with us; he were going to utilize the old chapel as our would tell us to "freeze' while he clattered playback room, he told us that he at- on confidently to the next button. tended Sunday mass there as a boy. We Scores of steps later we found ourselves invited him to look in and see whether he in a corridor leading to the organ loft. We thought it would be suitable for him, and passed a row of bellow -pedals, a carry -over lie directed us toward another door -the organ wrong door. Re had forgotten the way from pre -automation days when the with drew its breath from foot -operated bellows. over the years. Entering the chapel in the wall us, he paused an looked at the ruined in- To the right, a legend engraved up in his eyes: listed the registration -stop pedigree of this terior with tears welling on the Con- "Tien," he said, "Just think, it's been 50 mighty instrument, the largest foot in this place!" tinent. At the end of the corridor is the years since I last set now occupied by Marcel It was decided to use one end of the organist's study, chapel as the playback area since it was Dupré who holds the coveted position of main part St. Sulpice. Dupré's predeces- more or less separated from the organist of of the room. The lack of furniture and il- '.66 W. Ninth St., New York 11, N. Y. lumination was dealt with in a crude but

AUGUST, 1959 100 AUDIO effective manner: two battered chairs placed at a wide interval supported a long wooden lank, nail -studded and bristling with splinters; this constituted the work- table for the A. & R. department. For =cü/i,iUUAIIIII1pIp,0Y- light, a dormant electrical outlet was dis- 4huN., covered and put into service by an enter- "Picture on the Wall" prising engineer. The chapel, incidentally, became the assembly point for the moni- tor, microphone and intercom cables which had been hauled up the façade of the TELEVISION church from the recording truck below. The object of all this activity was to capture on magnetic tape the sound of a YOURS renowned instrument performed by an ar- tist who is thoroughly familiar with all its resources and capabilities. Of the latter, WITH NEW the St. Sulpice organ is richly endowed. Built by Cavaillé -Col during the last cen- tury, it is a product of the golden age of French organ building. As in the churches of Sacré -Coeur and Ste. Clothilde, Ca- ,_YEefictrood vaillé -Col achieved here a remarkable de- gree of purity of timbre. While his St. Sulpice organ is admirably suited to the fullblown Romantic works of Widor, it daVinci nevertheless does justice to Bach and Couperin because the contrapuntal voices are projected without blurring or rum- bling. The first test recordings were made be- fore midnight early last June. The church was empty and the old district of St. Sulpice was as quiet as a provincial village at night except for the distant bustle of You've dreamed of "picture on the wall television ". It's yours now with nearby Boulevards Raspail and St. Ger- the new Fleetwood da Vinci ... the set designed for custom installation main. Suddenly, the sound of this glorious instrument rolled into the star -filled Paris- . designed to be framed, as a picture, in a frame just right for your ian night and echoed through the Place decor. Fleetwood's new slim design lets a bookcase give a perfect "built St. Sulpice and the streets leading into the square. Transfixed by the music, a lone in" appearance without actually building in. bicyclist stopped to listen. It seemed as if the whole qunnier joined with him. A Revolutionary new 21 -inch* Fleetwood picture tube has non -glare safety glass laminated to tube face. Picture is brighter, viewing angle is wider, reflections are virtually eliminated. Wide band pass and excellent circuitry ... with no manufacturing shortcuts ... gives picture detail COMING HI -FI SHOWS that allows you to see an individual eyelash on a pretty girl. Sept. 11- 13- Milwaukee, Pfister Hotel. The Fleetwood da Vinci is available in two models. Model 900 -a two (Rigo) chassis system that features the lazy luxury of full electronic remote, Sept. 18- 20-Chicago, 8th Annual High Control, and Model 910 -with self contained controls. Fidelity Show and Music Festival, *Diagonal measurer Palmer House, (International Sight and Sound Exposition, Inc.) Sept. 25- 27-Rochester, N. Y., Sheraton THE gPEEt 1700d ®da Vinci Hotel. (Rigo) BUILT -IN BEAUTY Oct. 5- 10-New York, High Fïdelity Music THAT BELONGS Show, New York Trade Show Building. Presented by the Institute of High Fi- See delity Manufacturers, with "Decorate it at your your home with music" as the theme. hi fi (IHFM) dealer .. . Oct. 30Nov. 1-Buffalo, N. Y., Statler you'll Hotel. (Rigo) want it in Nov. 6-8- Seattle, Wash., New Washington your home. Hotel. (Rigo)

Nov. 13- 15-Portland, Ore., New Heath - man Hotel. (Rigo) Nov. 20-22 - Philadelphia, Benjamin Franklin Hotel. (Rigo) Write for name of dealer nearest you. Jan. 27- 31-San Francisco, Brooks Hall. (IHFM) CUSTOM TELEVISION Feb. 10-14-Los Angeles, Shrine Exposi- PEEta700 tion Hall. (IHFM) Crafted by Conrac, Inc. Dept. M Glendora, California

AUDIO AUGUST, 1959 101 DUAL CONCENTRIC SPEAKERS 'TAM N OY' EXCELLENT IN MONOPHONIC ENGINEERS' ERRORS SUPERB IN STEREO (from page 56)

Advocating now, as in the past, that the enclosure is an integral part of the speaker system, Tannoy has designed two new enclosures for use by the law. In a suit against engineers in stereo reproduction. Due to the inherent quality of the Dual Con- a judgment was recovered against them centric speakers to provide fundamental response at the low end of the which they appealed. In affirming that spectrum, and an ingenious loading device in the enclosure design, it is now possible to present a system of small physical dimensions and yet judgment the South Carolina court still maintain the extended frequency response of 30 to 20,000 cycles for stated a rule of law that is fundamental which the Tannoy Dual Concentrics are famous. These systems provide in the determination of the liability of absolute minimum harmonic and intermodulation distortion, excellent engineers for mistakes of this character. transients, and in addition, an integrated sound source so necessary for good "It seems to he well settled," said that BELVEDERE stereophonic reproduction. court, "that where a person holds him- For the 12" Dual Concentric (or the 12" Direct Radiator) there self out as specially qualified to perform is the 'BELVEDERE'. Designed for vertical or horizontal posi- work of a particular character, there is tioning, its external dimensions are 26" x 18" x 12 ". an implied warranty that the work 'which The 'BELVEDERE SENIOR' houses the 15" or 12" 'MON- he undertakes shall he of proper work- ITOR' Dual Cencentric. It is a compact 31 '/," x 23%" x 16 ", manship and reasonable fitness for its and is of solid 1 %a" construction. intended use and if a party furnishes Both cabinets are acoustically corrected, and handsomely finished a in either walnut or mahogany. specifications and plans for contractor to follow, he thereby warrants their Price's: 'BELVEDERE' with 12" Deal Concentric $203.00 sufficiency for the purpose in view. " 'BELVEDERE' with 12" Direct Radiator $144.00 Recently in Virginia the defense to 'BELVEDERE' only $ 65.00 a suit for the foreclosure of a mechanic's .... $223.00 'BELVEDERE SENIOR' with 12" Dual Concentric lien for architect's services involved the 'BELVEDERE SENIOR' with 12" Direct Radiator .... $164.00 'BELVEDERE SENIOR' with 15" Dual Concentric .... $264.00 sanie principles of law applicable to the 'BELVEDERE SENIOR' only S 95.00 of engineers. By the owner BELVEDERE services it SENIOR (Slightly higher In the 11'e4 I was contended that the work had been faulty and the cause of a loss. WRITE FOR DETAILS TANNOY (CANADA) LTD., TANNOY (AMERICA) LTD., Obligations Limited 36 WELLINGTON ST. EAST, TORONTO, ONT. BOX 177, EAST NORWICH, L. I., N. T. Circle 102A There the Virginia court outlined the extent of these obligations imposed by the law on engineers, architects and other professional workers. "The owner earnestly argues," said that court, "that it has suffered great loss as the result of the defects due to the failure of the architect to execute proper and sufficient plans and specifications. "The architect in the preparation of plans and drawings owes to his employer the duty to exercise his skill and ability, his judgment and taste, reasonably and without neglect. In his contract of em- ployment he implies that he possesses the necessary competency and ability to enable him 'to furnish plans and specifi- cations with a reasonable degree of tech- nical skill. "He must possess and exercise the care of those ordinarily skilled in the business and in the absence of a special agree- ment, he is not liable for fault in con- struction resulting from defects in the plans, because he does not imply or guarantee a perfect plan or a satisfac- tory result. "' A decision frequently adopted by the courts as an authority in these contro- CONNOISSEUR MODEL B versies involving the liability arising TRANSCRIPTION TURNTABLE from the performance of services by en- MADE IN ENGLAND gineers and other professional workers Be sure and see (and hear) the new Connoisseur Stereo Arm and Pickup with was rendered by the Maine Supreme sensational features. One demonstration and Court in the last decade of the past you will be convinced. ERCONA CORPORATION o Hill v. Polar Pantries, 64 S.E.2d 885, (Electronic Division) South Carolina, April 30, 1951 16 W. 46 Street, Dept. 42 New York 36, N. Y. Surf Realty Corp. c. Standing, 78 Circle 1026 S.E. 2d 901, Virginia November 30, 1953

102 AUDIO AUGUST, 1959 century. There suit had been brought for professional services and the defense interposed was that the services were not of benefit to the owner although no im- STEREO ON DISPLAY putation was made of either negligence or bad faith in the performance of the work. Granting a new trial to this profes- sional worker who had been met with an adverse decision in the lower court, this in your city... appellate court said of the law govern- ing engineering and other professional workers, "The responsibility is essentially the same as that which rests upon the lawyer to his client, or upon a physician to his patient or which rests upon anyone to HIGH FIDELITY SHOWS another where such person pretends to possess some skill and ability in some special employment and offers his serv- ices to the public on account of his fitness to act in the line of business for which he may be employed. "The undertaking of an architect im- plies that he possesses skill and ability with the newest and latest in stereo high fidelity sufficient to enable him to perform the from high fidelity required services at least ordinarily and leading manufacturers reasonably well and that he will exercise i and apply in the given case his skill and ability, his judgment and taste, reason- ably and without neglect." To this rule however the court set out an all important exception. "But the Don't miss these public showings Amplifiers - Pre -Amplifiers - undertaking," said the court, "does not of hi -fi equipment ... from the FM-AM Tuners - Turntables imply or warrant a satisfactory result. It most economical units for the Record Changers Phono will be enough that any failure shall not - - budget - minded to spectacular Cartridges Microphones be by the fault of the architect. There is - - no implied promise that miscalculations home music theaters ... compare Music Control Centers - Speak- may not occur. and enjoy them all. ers - Speaker Enclosures - "An error of judgment is not neces- Equipment Cabinets - Finished sarily evidence of a want of skill or care, Complete Stereo and Mono- and Assembled or Do -It -Your- for miscalculations are incident to all phonic High Fidelity Systems self Kits the business of life." To this is added an outline of the duties of the professional worker and the principle of law gover- ing all professional services of this THREE FULL DAYS OF CONTINUOUS DEMONSTRATIONS character. FRIDAY, SATURDAY, AND SUNDAY "Those who employ hint have a right to his best judgment, to his skill, to his FROM 1 P.M. to 10 P.M. FOR EACH SHOW advice, to consultations with him and to his absolute fidelity and good faith and when he has contributed these things to the person who employes him, his duty RICO HIGH FIDELITY MUSIC SHOWS, Fall 1959 has been fulfilled."8 Milwaukee September 11 -12 -13 Pfister Hotel "Ordinary Care and Diligence," not a Guarantee Rochester, New York September 25- 26-27 Sheraton Hotel

In another instance involving this Buffalo, New York October 30-31 Nov. 1 Statler Hotel same feature, the obligations and liabili- Seattle November 6-7-8 New Washington Hotel ties of engineers and other professional workers, a New England court a hun- Portland November 13 -14-15 New Heathman Hotel dred years ago said of the rule of law at that time which still subsists, Philadelphia November 20 -21 -22 Benjamin Franklin Hotel "The professional man contracts that he will use reasonable and ordinary care ADMISSION 75t and diligence in the exertion of his skill and the application of his knowledge to

° Coomba v. Beede, 36 Atl. 104, Maine, May 7, 1896 RIGO ENTERPRISES, INC. 500 N. Dearborn, Chicago 10, III.

AUDIO AUGUST, 1959 103 WHERE accomplish the purpose for which he is employed. THERE'S "He does not undertake for extra- A ordinary care of extraordinary diligence FINE any more than for uncommon skill. The TAPE general rule is well settled that the con- tractor for services to be performed for RECORDER... there's another, agrees to exert such care and skill as men of common care and com- mon prudence usually exert in their own business or in a similar kind. He agrees to be responsible for the want of such care and attention and he stipulates that in no event, without an express con- tract for that purpose, for any greater liability. "9

° Leighton v. Sargent, 27 N.H. 460, De- cember, 1853

FITTITE___ JAll note to BELL owners (from page 91) To insure optimum recording quality gress and the United Nations. His first re- cording Is well executed, with an assist from with your excellent machine, the several of El-Bakkar's musicians, and should win him many friends. #211.. . recommended tape is Irish On n visit to the night clubs of Lebanon's and for uninterrupted recording, capitol city. the women take over. Of the seven vocalists heard during the evening, irish #724 with its 6 lb. tensile strength only one is a man and he has a female ac- gives you one lull hour at 71/2 i.p.s. complice. The tour, recorded on the spot, is a lively one and encompasses an engaging Send for technical bulletin. variety of style and accompaniments. Again a Western influence crops up, but is soon sub- ORR INDUSTRIES INC. dued in a welter of Oriental melodies. Opelika, Alabama Circle 104A COVER PHOTO The installation shown on the front cover JUST WHAT IT TAKES of this issue is obviously designed to be "lived with." Not garish in appearance, but TO MAKE THE SHOW... simply neat and efficient throughout, it in- corporates a Fisher 90X FM tuner with space provided for a multiplex adapter, a Fisher 400 stereo preamplifier, two Leak L50 -plue 50 -watt amplifiera, two Bozak 305 speaker systems in custom enclosures, a Garrard RC98 record changer with a Picker- ing 371D cartridge, and an Andrea TV set. There is a KLH Model Six as an auxiliary speaker on the adjacent sun porch with a volume control at the listening position.

THE EASY TO READ - EASY TO OPERATE STUDIOSOUND S -301 -R PROGRAM EQUALIZER

Assure the success of your shows or recording sessions with the always de- pendable S -301 -R ... check these top performance StudioSound specifications: LOW- FREQUENCY EQUALIZATION: 12 db in 2 db steps at 100 cps & 40 cps (shelving Characteristic). HIGH- FREQUENCY EQUALIZATION: 12 db in 2 db steps at 3, 5, 7, 10 and 15 kc. (shelving characteristic). HIGH AND LOW FREQUENCY ATTENUATION: 16 db in 2 db steps. The heat duct along the back of the as a chimney and there are has built -in flexibility, it's available complete on one panel cabinetry acts This star performer aluminum deflectors to conduct heat to back or in money saving kit form. and up. Slots are located on the toe plate fine components vital to a good show are: StudioSound Filters, below the cabinets for ventilation when the Other StudioSound below the Pads and Networks. Special components made to order. For further information doors are closed. The grill cloth contact: controls provides ventilation for the power amplifiers, and is removable for servicing. STUDIO SUPPLY CO. The room is fully carpeted and has one fully draped wall in addition to a partially 711 So. Victory Blvd. Burbank, California Box Z -8 -59 draped wall opposite the unit. One wall, adjacent to the record cabinet of the unit, Circle 104B is walnut paneled. 1959 104 AUDIO AUGUST, PRODUCT REVIEW BIG SOUND from (¡rolll pall, -

utes. Frequency response at 15 fps in within SMALL enclosure! ±2 db of the level rat 1000 cps. between 50 and 7000 ceps, and within ±:l db from 7000 to 10,01111 cps. The signal -to -noise ratio is better than 45 db unweighted at 1000 cps. Separate recording and playback heads and the NEW RAZI£R %lea a14"

TRUE BOOKCASE SIZE

PAIRED FOR STEREO AT $99.50

TWO -WAY SYSTEM (each enclosure has a separate woofer and a tweeter)

NATURAL WOOD FINISH (not printed wood graining)

HIGH EFFICIENCY (no more than 10 watts per channel required for concert hall volume) amplifiers are provided to facilitate monitor- ing and instantaneous playback. Manufac- tured by Electrical & Musical Industries. Ltd.. of Engluant. the E. M.1. portable recorder is distributed in the United States by Ercona Corporation, 10 W. 46th St., New York 36, N.Y, Yser net price. $395.00-

MAGNECORD Stereo ayne-cordellr. The Series 100 Mng- necordette is a portable professional -type tape recorder which both records and plays back in -line stereo. A two -speed machine, operating at 71.. and 3% fps, it is HMO cap- able of standard monophonic recording and playback when desired. Separate VU meters and gain controls are Incorporated for each channel, as well as n finster gain control which operates on both channels simultane- ously. Frequency response IS 40 to 15.000 cps +2.0 dl at 71_ ips: 50 to 751111 +2 db at 3% ips. Inputs are provided for hero high-impe-

The %/f.a CT/!4 is truly the best value in small loudspeakers in America today ... performance from below 70 cycles to 15,000 cycles; Power handling capacity is 12 watts continuous, impedance, 8 ohms. Small enough to dance microphones, nl SO for auxiliary devices fit in your bookcase! Only 101/2" high, i57/ß" long, i17/" deep; such as tuners. phono cartridges. etc. Two- the Monte Carlo 3/4" cabinet is hand -rubbed Walnut motor drive system hohl,. flutter and wow to finish in natural wood, and is equipped with four less than 0.3 per cent. Noise level is down concealed plastic more than 48 db. Binaural feet. Tweeters are mounted for right monitoring is and accomplished by means of a panel- mounted left placement. Only $99.50 per pair ... hear the phone Jack. Playback outputs are cathode Frazier Monte Carlo at your dealer's ... you will followers which deliver 1.0 volt from normal be amazed at the performance! output level. This is truly a tine instrument for the serious hobbyisr who demands n high Backed by the tr;tir measure of audio quality as well as dependa- Reputation for Quality hility of perro rata uve. Magnecord Incision, Midwestern Instruments, Inc., 41St St. and Sheridan Road. MISS. I MN. Yser net price, in portable carrying cane. $449.95. Send for RAZ£R Bulletin DB 69 INTERNATIONAL ELECTRONICS PT6 -6A 2sp, full /I /2tr, rec /pb, port $405.00 CORPORATION PT6 -61 rec pb ampl, port 295.00 2649 BRENNER DRIVE DALLAS 20, TEXAS

AUDIO AUGUST, 1959 105 SAVE HALF NOW ASSEMBLE -IT-YOURSELF 2 NO SPECIAL SKILLS PAY KIT -BY -KIT 9chdét ELECTRONIC ORGANS

Now you can afford an electronic organ. Whether you choose the full Concert model or the smaller Consolette, you have an organ equal to any made by the foremost manufacturers. In addition, you save

over s the cost because you assemble it yourself ...and you enjoy the thrill of achievement. Too, you purchase each kit only when you are ready for it.

2 different MODELS 2 different SIZES 2 different PRICES W-`.` , MAGNEMITE Ito ttery- Opernteft Spring -Motor Tope Re- CONCERT CONSOLETTE corder. Accuracy and simplicity of operation MODEL MODEL are stressed in the design of the VU Magne- * TWO FULL SIZE PIPEORGAN MANUALS, * OCCUPIES ONLY 2' x 3'2" FLOOR SPACE mite portable tape recorder. Professional per- 122 KEYS * TWO PIPE-ORGAN MANUALS, formance is provided by the Incorporation of * OCCUPIES 3'5" x 4'7" FLOOR SPACE 122FUKLYSIZE a VU meter to act as n recording and output - COUPLERS * 22 STOPS - ABOVE -KEYBOARD TABS level indicator and "A" and "13" battery * 32 BASSSPEDÁ S it 13 HEEL -AND -TOE BASS PEDALS voltmeter. Special ballistic characteristics * ASSEMBLED CONSOLE * 7 FULL OCTAVES OF TONE (DOWN TO 32 tt CONFORMS TO AMERICAN GUILD OF CPS) are incorporated In the meter to ensure ORGANISTS SPECIFICATIONS FOR PIPE * BUILT-IN SPEAKERS OPTIONAL avoidance of overloud of peak signals. Shunt- ORGANS * ASSEMBLED CONSOLE ing of the output signal during recording is * COMPLETE STEP-BY-STEP INSTRUCTIONS * COMPLETE STEP-BY-STEP INSTRUCTIONS avoided by employing an isolating amplifier. The VU model is similar to other 3Ingnemites in general characteristics. It is available with 10" LP RECORD DEMONSTRATING BOTH MODELS operating speeds ranging from 15/16 to 15 AVAILABLE FOR $2, REFUNDABLE UPON PURCHASE fps. Frequency ranges run from 300 -2500 cps to 50- 15,000 cps. depending on operating FREE NEW 1959 EDITION OF 16 PAGE ILLUSTRATED BOOKLET ON REQUEST speed. At 15 ips the machine meets primary NARTB standards. Because this recorder is Write Now - See What Fine Instruments You Get At Such Great Savings primarily n professional instrument, available for n wide range of specific uses calling for The SCHOBER ORGAN Corporation 2248 -K BROADWAY NEW YORK 24, N. Y. various accessories. it is suggested that in- *- Designed by Richard H. Dorf. terested readers get in touch with the manu- SCHOBER KITS ALL OVER THE WORLD facturer for exact price Information. Ampli- fier Corp. of America, 398 Broadway. New Circle 106A York 13. N.T. User net price, 7% -ips twin - track model, $365.00. NEWCOMB NOW ..enjoy your H/ -f/ OUTDOORS Stereo Tope Recorder. The Newcomb Model SM -310 is n rugged. simple. foolproof instru- PATIO, GARDEN, TERRACE, PORCH ment with the precision and dependability required by the professional. combined with the straightforward operation desired by the serious amateur. Transport control is cen- with the new WT -6 tered in a "joy stick" with completely logical positioning -fast forward 13600 feet in two minutes). right : rewind. left : record or play- ATLAS HI -FI back. down. Partial stick movement gives slower reel speed. An edit position permits COAX -PROJECTOR turning reels by hand. The SM -310 is a two- weather speed (7s and 3% ips), two -channel machine all- construction...install it, forget W... /1 for either stereophonic or half -track mono- or take it with you wherever you listen. phonic recording as well as playback. Two inputs with mixing controls are provided for each channel, also two illuminated VU meters. True HIGH FIDELITY TWO -WAY system -not Handles reels of any size up to 10s /- 1n., in- cluding NARTB hubs. Tape drive is by means just a "compromise" of two horns coupled to y "'GOP' of n single powerful fully -synchronous cool - v- t a single diaphragm. The WT-6 comprises a A running motor. Frequency response is 30 to weather -proof cone type driver (with 6 -inch 15.000 cps ± 2M db at 7% ips; less than 0.25 throat) coupled to its individual woofer horn; per cent at 3% ips. Equalization is NARTB a separate pressure -type driver loaded to its standard. Output is approximately 1.3 volts separate tweeter horn. The built -in crossover from cathode follower, each channel. The is ideal the indi- electronic filter supplements the electro- SM -310 an instrument for vidual who Is deep in the art of tape record- mechanical frequency -limiting characteristics ing. Newcomb Audio Products Co.. 6824 Lex- of the 2 individual reproducers - providing ington Ave.. Hollywood 38. Calif. User net for smooth frequency division as each price. including case, $499.50. speaker functions within its engineered N -64c Uni -dir dyn mic, w /cord. plug .. $60.00 range of frequencies. N -36c Slim omni -dir dyn mic, w /cord, plug 51.60 All. weather ... high efficiency ... compact

. . for all indoor and outdoor uses . universally adjustable "U" -type rugged steel mounting . finished in high temperature baked modern beige enamel. net POWER RATING 15 watts continuous FREQ. RESP. 140-15,000 cps $34.50 IMPEDANCE 8 ohms. DISPERSION 120° DIMENSIONS bell opening 15 ", overall depth 12" See the WT-6 at your local distributor. Send for catalog A-8 ATLAS SOUND CORP. 1449 39th St., Brooklyn 1B, N. Y.

Circle 106 B

106 AUDIO AUGUST, 1959 NORELCO NEW SOUND Stereo Tape Recorder. Engineered and man- ufactured by Philips of The Netherlands, the New new Continental "400" features halt -track stereo playback and quarter -track stereo and EXCITEMENT monophonic record and playback for tape economy, three speeds -7 %, 3% and 1% fps -for versatility, and simple piano -key con- trols for ease of operation. It is fully com- FOR THE HI-FI PROFESSIONAL 55 patible with conventional recorded tapes. The unit comprises a tape -drive mechanism, two the Ultimate preamplifiers with controls, two 4 -watt power amplifiers, and a Norelco wide -range speaker, STEREO AGE! all housed in a high -fashion portable carry- STEREO CARTRIDGE LOUDSPEAKERS

Never before so many quality features in loudspeakers -yet priced for the modest budget! Dual cones for breathtaking wide range performance! Twin voice coils in 12" loudspeakers, with flexible impedances of 4, 8, or 16 ohms, enabling you to select the impedance you require! Non -resonant cast aluminum girder constructed frames! Fully tropicalized for finest operation in any climate. For stereo or monaural -singly or in matched pairs. log case. Also furnished is a Norelco dynamic stereo (dual element) microphone. Only a HEAVY DUIY CAST ALUMINUM I. u., second speaker is needed for stereo playback. CONSTRUCTION Dubbing facilities permit recording sound on sound. The Continental 400 has inputs for recording from microphone, tuners, and COLUMBIA MAGNET ASSEMBLY, phonograph, with facilities for mixing the WEIGHT SI 5 07 microphone input with either of the other two. Professional 55 An output jack for monitoring with stereo ... headphones is also provided. Special Philips Cost $28.95 magnetic heads with a gap of only 0.00015 in. 4. 8 AND 16 OHM make possible extended high- frequency re- IMPEDANCES This new transparent cartridge is sponse even at lower recording speeds. Fre- the professional's version of the quency ranges at the various speeds are: 7% popular Columbia CD. A high -com- Ips -50 to 18,000 cps; 3ÿ¡ fps -60 to 14,000 pliance model with excellent tran- cps ; 1' ips-60 to 7000 cps. Noise level is TWIN VOICE COILS sient response, it uses a .5 -mil dia- down 55 db, and flutter and wow are less mond stylus and is designed for than 0.3 per cent. High Fidelity Products transcription turntables. Comes Division. North American Philips Company, DUAL CONES complete with 4 miniaturized plug - Inc., Hicksville, N.Y. User net price, $399.50. in equalizing networks for low- and high -level inputs. NEW! LORENZ S -1288 ROBERTS Value-packed basic 12" loudspeaker of advanced CURVES, FACTS AND FIGURES PROVE IT design, with dual cones and twin anice coils. Monophonic Tape Recorder. The new Roberta Choice of Impedances of 4, 8, or 16 ohms on Model 191 is a full -track monophonic recorder one speaker) Frequency response: 18 to of special 15,000 cps. Magnetic assembly weight 61.5 interest to radio and TV stations. oz. Power rating: 30 watts peak. $44.50 sound engineers and recording studios. A two- speed recorder, it meets professional specifica- I tions, having a frequency range of 40 to 15,000 NEW! LORENZ S -1288 IC epa ±2.0 db at 7% ips, and 40 to 9500 cps A complete system in one convenient unit! Brilliant full range diaxial for the most critical connoisseur. Consists of Lorenz S -1288 plus twin tweeters on rigid metal bracket and high pass cross- over Dual cones and twin voice coils 18.18,009 cps 35 watts peak 4, 8 or 16 ohms $67.50

NEW! LORENZ S -888 A wide range speaker wonderfully adapt- able to single or multiple use. Dual cones Ask for for thrilling broad sound response, cast Bulletin E -331. Check the aluminum girder frame 30.14,500 cps Professional 55's superiority in: 18 watts peak 8 ohms $21.50 linearity ... separation .. , needle point impedance ... low mass ... AM freedom from hum and distortion NEW! LORENZ S -388 ... output level... and ruggedness. The perfect match mate for Lorenz 12" or 8" speakers. Armored horn -type 21/2 tweeter YOUR OWN EARS PROVE IT with plastic cone for efficient 120 degree high -frequency sound dispersion. Extends Better still. Your own ears will con- the range of any system! 2,000.18,000 vince you the Professional 55 is cps 20 watts peak 5.5 ohms $8.50 your best investment. Ask to see and hear it at your distributor's HP -1 HIGH PASS CROSSOVER today! Crosses over at 2,000 cps. at rate of 3 db +3.0 db at 3% ips. Flutter and wow content per octave -feeds highs to tweeters, lows to CBS ELECTRONICS is less than 0.2 per cent rms. Noise is 55 db woofer. Extends speaker system range to limit of A Division below recorded zero level. The hysteresis - audibility. For use with 2 or 3 way of synchronous drive motor systems. $4.95 Columbia Broadcasting System, is belt- coupled to a Inc. speed -stabilized flywheel NO Danvers, /capstan assembly. Massachusetts The amplifier features professional-type ter- At High Fidelity Dealers Everywhere. Distributed in Canada by minal board wiring and has (I watts output FREE Cetalea -Write Dept. A-8, CANADIAN GENERAL ELECTRIC CO., LTD., TORONTO for feeding the built -in playback speaker. High - , PRODUCTS. impedance Ltd. prealnp output is also supplied for 314 'roadway, Now Te,Y I2. N. T. WOnh 4.0,00 feeding external equipment. Equalization is GWYN. O. S. 0161IbaI,. Io, LONIS HIRN rld,I.I Load.p,L,r Circle 107A based on EARTH standards. VU meter is Circle 1078 AUDIO AUGUST, 1959 107 IMPORTANT Volume of AUDIO Magazine ANNOUNCEMENT January- December 1957 A full year of AUDIO durably preserved in a handsome binding for quick, easy reference at all times. Only a limited number available -so, be sure to order your copy now! No. 122 1957 Bound Volume of AUDIO $10 Postpaid. SHIPPED SAME DAY WE RECEIVE ORDER! (U. S. DELIVERY ONLY)

ND9ooK Of SO enient service to AUDIO 'NA 40 HANDBOOK OF SOUND REPRODUCTION your books renders. Order by Edgar M. Villchur T rely by mail -save time and Right up to date, a complete course on sound reproduction. Covers everything from the basic elements to individual travel, we pay the postage. chapters of each of the important components of a high fidelity Q system. $6.50 Postpaid.

NEIV! Jo. 120 THE 4th AUDIO ANTHOLOGY $2.95 Postpaid This is the biggest Audio Anthology ever! No. 112 2.ontains a wealth of essential high fidelity TAPE RECORDERS AND TAPE RECORDING :now -how in 144 pages of complete arti- by Harold D. Weiler :les by world-famous authors. A complete book on home recording by the author of Nigh Fidelity Simplified. Easy to read and learn the techniques required for professional results with home recorders. Covers room acoustics, microphone tech- niques, sound effects, editing and splicing, etc. Invalu- able to recording enthusiasts. No. 115 Paper Cover $2.95 Postpaid. McPROUD HIGH FIDELITY OMNIBOOK Prepared and edited by C. G. McProud, publisher of Audio and noted authority and pioneer in the field of high fidelity. Contains a wealth of ideas, how to's, what to's and when to's, written so plainly that both engineer and layman NEID! can appreciate its valuable context. Covers planning, problems with decora- No. 119 tion, cabinets and building hi -fi furni- HIGH FIDELITY AND THE MUSIC LOVER ture. A perfect guide. $2.50 Postpaid. by Edward Tatnall Canby An up -to -the- minute guide that shows you how to get the best out of your hi -fi records and tape recorder. Mr. Canby discusses in detail the speaker, the amplifier, the radio tuner, the record player and the tape recorder. He shows you how to save time and money, and get the hi -fi equipment that suits your particular, needs. Illustrated with line drawings. $4.95

'are an rr;,air ol HI-Fl

No. 118 NEW! How -to Book on Hi -Fi Repair CARE AND REPAIR OF HI -FI- Volume I by Leonard Feldman Latest information on hi -fi components for efficient repair and main- AUDIO Bookshelf tenance. Complete, down -to -earth information that is not punc- mathematics. Helpful to the hi -fi enthusiast, RADIO MAGAZINES, INC., Dept. A tuated with complicated technician or engineer, this first volume includes many important P.O. Box 629, Mineola, New York features: Example schematics with tube layouts, descriptive illustra- 156 pages profusely Please send me the books I have circled below. I am enclosing the tions and hook up diagrams, buyers' guide. illustrated. $2.50 Postpaid. full remittance of $ (No. C.O.D.) All U.S.A. and CANADIAN orders shipped postpaid. Add 50e for Foreign orders (sent at buyer's risk). BOOKS: 110, 112, 115, 118, 119, 120, 122 NAME ADDRESS

CITY ZONE_$TATE_ calibrated from -10 to +3 db. Interlocking ization) is 30 to 20,000 cps at 7% ips ; 30 controls prevent accidental erasure of recorded to 16,000 at 3% ips, and 30 to 8000 cps at tapes. Notwithstanding the fact that it is a 1% fps. Flutter and wow are 0.1, 0.2, and complete record /playback system, the 191 0.25 per cent at the three respective speeds. measures only 15%"h x 141 "w x 91/4"d, and A powerful motor of the capacitor -starting weighs but 28 lbs. Roberts Electronics, Inc., type assures uniform speed over a range of 1041 N. Sycamore St.. Los Angeles 38, Calif. line voltages from 90 to 135 volts. The erase User net price, $325.00. head is selective and may be used to erase any one of the four tracks individually. An automatic tape -stop switch stops tape with SUPERSCOPE metallized leader at end of reel. Tandberg of America, Inc., S Third Ave., Pelham, New Stereo Recorder -Playback System. Every- York. User net price, as shown but with thing required for stereo recording and play- second -channel recording amplifier mounted back. including two VU meters and two power In an auxiliary matching mini -case, $489.50. amplifiers, is incorporated in the Sony "Stere- corder." A precision -built instrument in all respects, it incorporates a hysteresis- synchro- TELECTRO nous drive motor and affords instant selection of 71- and 3% -ips drive speeds. Frequency re- Series 900 Tape Decks and TRY -Il Record/ spouse is 50 to 15.000 cps + 2.0 db at 7% Play Amplifier. The Series 900 offers a variety ips; 30 to 12.000 cps at 3%, ips. Flutter and of facilities in a simple tape -transport me- wow components are less than 0.2 per cent chanism without electronic equipment. For those who wish a complete recording system, including record and play amplifiers and the necessary bias oscillators. the Telectro line includes the Model TRY -11 record /play pre - amplifier, which provides for recording from low -level microphone input or from a high - level source such as a tuner, and in the play mode has an output of approximately 5.0 volts. Controls on the TRP-11 include n re- cord /play selector, equalization switch, noise balance, and gain control. Recording level is shown by n VU meter. The tape transport itself is available in five forms, depending on the head complement. Model 900 -1 is equipped for monophonic recording and playback and for 2- or 4 -track stereo playback ; 900 -2 has three heads-monophonic erase and play /re- cord heads, and a 4 -track stereo. head which may be used as a monitor during monophonic recording, or for playing back both 2- and

and 0.3 per cent at the higher and lower speeds. respectively. Stacked high- frequency erase head erases both channels when record- ing stereo, or one channel (half track) when optimist? recording monophonically. Individual level control is afforded for each channel, plus master gain control for simultaneous adjust- ment. Automatic head -demagnetizing circuit prevents residual magnetism, with resultant minimum tape hiss. Automatic tape lifters protect recording heads and tape during fast forward and rewind. Designed for both cus- That's putting it mildly. If you really tom installation and portable use, the Stere- corder will satisfy the most fastidious user. want to cook with gas on your next Superscope, Inc., Sun Valley, Calif. User net P.A. installation, choose from the Uni- price, $395.00. Note: A wide range of acces- sories is available for use with the Stere- versity range. Then you'll be sure of corder, and it is suggested that those interested getting the most economical speaker in purchasing one write for descriptive 4 -track stereo tapes ; 900 -3 has two heads, material. stereo erase and 4 -track record /play ; 900 -4 for the right amount of power, the is equipped only for playback, and has a single 4 -track head which will play mono and stereo right coverage, the right frequency TANDBERG tapes; 900 -5 has three stereo bends, making response. The world's most compre- it possible to monitor a tape during recording. Stereo Record -Playback System. Notwith- All models are for 3 -speed operation-7%, hensive range of P.A. speakers is standing its compactness, the Tandberg Model 3% and 1?i, ips. Flutter and wow content is in new product 5 -2 performs virtually every task which could less than 0.25 per cent. Signal -to -noise ratio described University's be expected of a modern tape recorder. A 3- is better than 50 db when used with the catalog. It's FREE. Also, invest $1 in speed machine (7., 3% and 1% ips), it has TRP -11. Speed accuracy is within NARTB facilities for 4 -track stereo and monophonic standards. The mechanism employs a single the all -new 64 -page University Tech - recording and playback, playback of 2 -track motor with belt drive to the reel hubs and nilog, the authoritative reference stereo, and playback of half -track and quarter - to the capstan. the latter having a large fly- track monophonic tape. The unique 4 -track wheel for speed stability. Transport controls book for planning public address in -line precision laminar head has double are push- button operated. They include: stop, speaker installations. See your local mu -metal shielding to give crosstalk rejection rewind. wind, play, and pause. The TRP -11 of 60 db. Frequency response (NARTB equal- incorporates n VII meter. Frequency response distributor, or write to Desk R-4, is 50 to 15,000 cps +3.0 db. Inputs are sup- University Loudspeakers, Inc., 80 So. plied for a low -level microphone and high - level tuner, with maximum recording level Kensico Ave., White Plains, N. Y. sensitivity of 0.002 volt. Telectrosonic Corpo- ration, 35-18 37th St.. Long Island City, N. Y. User net price : Model 900-1 tape transport, $89.95 ; 900-2, $104.00 ; 900 -3. $101.00 ; 900-4, $89.95 ; 900 -5. $126.25. Model TRP -11 record - play preamplifier, $65.00.

UH ER Multi -use Tape Recorder. A compact and ideal tape recorder for most tape applications excepting those where a maximum frequency range is required for high fidelity uses, the THE WORLD'S MOST COMPLETE RANGE Uher Universal offers facilities not duplicated RADIAL HIGH FIDELITY WEATHERPROOF PAGING with most other machines. With three tape WIDE -ANGLE SUPER -POWER SUBMERGENCE -PROOF

speeds -3 %, 13k, and 15/16 ips-the Uher is DIRECTIONAL EXPLOSIONPROOF . TALK -BACK

AUDIO AUGUST, 1959 109 and edit functions, while the outer ring con- trols fast- forward and rewind. Universal head - mounting bracket on all decks comprising the Series 85 permits changing or adding to head - 4iM4p '- complement at will. All models are equipped with long-wearing laminated heads, tape lift- ers, non -resonant pressure pads, and auto- 114 \> matic tape run -out switch. The transport may SAVE be operated horizontally or vertically. Fre- quency response is 30 to 14,000 cps ± 3.0 db. Signal -to -noise ratio is better than 55 db. Flutter is less than 0.2 per cent at 7% ips. Front panel speed change, 3% and 7% fps. The RP62C record /playback preamplifier is 25% engineered to match the operating characteris- tics of the Series 85 deck. Bias oscillators may he synchronized for stereo recording.

serve a This is our sufficiently flexible to as dictating machine at the lowest and as a conventional music recorder at the highest. where the fre- GROUP SUBSCRIPTION PLAN quency range is said to be 40 to 16,000 cps. Remote-control unit and Synchro -Akustomat -a device for actuating an automatic slide Now you, your friends and co- workers changer by means of a recorded tone signal - can save $1.00 on each subscription are available accessories. and the unit is to AUDIO. If you send 6 or more sub- provided in a travel -style case which accom- scriptions for the U.S., Possessions and modates microphone, cables, and tape supply. they will cost each subscriber Hysteresis synchronous motor, self- contained Canada, speaker system, separate recording and play- 1/4 less than the regular $3.00 each, back volume controls, and many other useful one year subscription price. Present and desirable features. Made in Western subscriptions may be renewed or ex- Germany, the Uher is distributed in the U.S. tended as part of a group. Remittance solely by Warren Weiss, c/o Trans -World to accompany orders. Electronics, Inc., 1650 Broadway, New York 19, N. Y. User net price, $299.95. Erase current and bias are adjustable. NARTB tape equalization is fixed in recording, vari- able in playback. Distortion is less than 1.0 AUDIO is still the only publication VIKING per cent at indicated normal recording level. devoted entirely to The W4SX enclosure, available in polished Two -Speed Stereo Recorder -Playback. The walnut or fruitwood. accommodates the 85 recorder vertically- mounted Audio illustrated comprises the Viking Series tape deck and two Series 35 tape deck. and two Model RP62C RP62C's. The bottom panel is removable for Broadcasting equipment record /playback preamplifiers. mounted in a installation of power amplifier(s) or mixer Acoustics Model W4SX enclosure. The 85 1s the finest controls. Viking of Minneapolis, Inc., 9600 Home music systems Viking deck designed for the home music Aldrich Ave., South. Minneapolis, Minn. User system. Containing two motors -one re- net prices : Model 35ES tape transport Recording for cord. the other for rewind, fast forward and equipped for monophonic and stereo record - PA systems footage counter -It uses a dual concentric playback- erase. $147.00. Model RP62C record/ Record Revues switch knob to control all mechanical opera- playback preamplifier, $77.50. Model W4SX tion. The inner knob controls forward, stop, cabinet, $39.50.

I Please print Name Tape Accessories Address

unit functions precisely as does a turntable New Renewal ERCONA strobe disc. To use the Irish stroboscope, the Tape Splicer. An indispensable accessory user holds it lightly but firmly against the Nam for any tape recordist, this new British -made surface of the moving tape. Extremely low - friction needle bearings allow the disc to Addren splicer is extremely simple to use and can he employed both for mending broken topes revolve freely in correspondence with the tape and for editing purposes. Made of nickel- New Renewal

Nam Address

New Renewal

Name Address

New Renewal Nam plated brass. the BIB splicer comes mounted on n flock -sprayed base, or can be mounted Address directly on any tape deck. The body of the splicer has two pivoted clamps which lock the motion. Accurately scaled and ruled, one of in a channel. Both vertical and these devices should he included in the gear Renewal tape sections New diagonal mitres are provided for either edit- of every serious tape recordist. ORRadio In- ing or mending. Horizontal mitres are also dustries. Inc., Shamrock Circle, Opelika, Ala. Nam provided for use in trimming off surplus User net price. $4.95. Addren mending tape. Distributed in the United States by Ercona Corporation. 16 W. 46th St., New York 36, N. Y. User net price. $3.95. ROBINS New Renewal Bulk Tape Eraser. This device is for the IRISH serious recordist who wishes to lower the U. S., Possessions, and Canada only noise level on tape to degree greater than Tape Stroboscope. Shown checking the is possible with the average home tape re- speed of an Ampex 601 is the Irish tape corder, also for those persons who wish to RADIO MAGAZINES, INC. stroboscope. a device consisting of a handle save the time normally consumed by running an erase head. The P. O. Box 629, Mineola, N. Y. and n Bakelite disc marked off to three con- tape from reel to reel over centric rings of radiating lines, with each Robins Model 99 will erase a full reel of tape ring representing n nominal tape speed. The in a matter of moments. By simply placing a

110 AUDIO AUGUST, 1959 Out-Performs any STEREO TAPE RECORDER

..r.to 44 t `P e!r

reel on the spindle and rotating it. the re- cordist immediately erases the signal, lowering the background noise level by 3 to 6 db below Tandberg average erase head levels. It can handle reels MODEL 5 -2 up to 10 ins. in diameter, and erases tapes up to one -half inch wide. It operates on ordi- Exclusive Tandberg features assure TO MAKE YOUR nary 117 -volt 50/60 -cycle house current. Rob- ins Industries Corporation. 36 -27 Prince St., the finest stereo quality and per- Flushing, STEREO AND HI -FI TAPES N. Y. List price, $33.00. formance. You get more tape value, ESK series Rec care kits $2.00 -5,00 too -up to 8 hrs. and 32 min. on one LAST LONGER, "Gibson Girl" tape care kit 3.50 reel! Tandberg Stereo plays back two SOUND BETTER and four track tape. Besides incom- parable stereo performance, it is the ROBINS ME -99 MAGNETIC BULK ERASER Miscellaneous first to offer recording and playback Improve your tape recordings by removing com- on four monaural tracks. And only pletely recorded and unwanted signals. The ME- Tandberg offers superb tape motion 99 reduces background noise levels of tape from BLONDER -TONGUE at I ?a I.P.S. 3 to 6 db below normal erase head level. If your Audio "Baton." tape deck is geared to stereo and does not have This is a unique high - stereo fidelity instrument for providing complete Monaural tape recorders are avail- erase, the ME -99 does the job quickly and control of the audio spectrums. It provides a able in 2 or 3 eliminates sending tape 28 -db control range speeds, with or without through for compensating for single -track erase deficiencies in program source or in repro- foot pedal for remote control. head twice. In a matter ducing equipment. Nine compensator controle of seconds it demagnetizes are octave- spaced at 40, 80, 160, 320, 1280, Stereo Features 2560, 5120, and tapes up to %a inch wide 10,240 cps. Input is 1.5 volts 3 operating speeds 1 r/e, accepts reels up to I0 ". - 334, List $33.00 and 7''2 I.P.S. t-n nrn'n!,p mttrtrrtrrTrruiwcql 4 -track Stereo, 4 -track monaural recording and playback, plus ROBINS TAPE HEAD DEMAGNETIZER playback of 2 -track Stereo and MODEL HD -6 CC'CMINIONItt: !4 -track monaural Removes any residual permanent magnetism .>r?r s^i r-Y". 2 built -in preamplifiers and from your recording head thus eliminating high power amplifiers noise level and harmonic distortion caused by 4 -track record -playback head magnetism. Protects your tapes and your and 4 -track erase head which head rms, maximum, with Impedance and assures of 125,000 can erase 1 or 2 tracks at a time professional recordings. An extended ohms at 1000 cps. pole -piece provides Output is 1.5 volts rms, Automatic tape stop at end of easy access to the heads of maximum, with impedance of 20,000 all leading ohms at play makes 1000 cps. Hum and noise are 60 db below of tape recorders. -(, rated output. Frequency range is 20 to 20,000 One lever control for tape start - List $10.00 cps ± 2 db. Harmonic distortion is well under stop, fast forward and rewind, o 1.0 per cent. A panel- mounted switch permits record -play by-passing the Audio Baton when desired. Distinctive style, mahogany fin- This is an excellent instrument for fectionist the per- ish, leather case in reproduced sound. Blonder - ROBINS M/M MAGNETIC Tongue Laboratories Inc., 9 Ailing St., Newark RECORDING HEADS 2, N. J. User net price, $119.05. NOW Upgrade your present recorder, convert to stereo another Tandberg FIRST! with these precision magnetic recording and erase CLAROVOX heads. Consider Model SQS, a 1/4 Tandberg Model track stereo Record Handler. Especially designed to pre- 4 record /playback head, precisely engineered for vent damage to records during handling, conversion the The ONLY Four -Track of many popular tape recorders. Note Clarovox "Miragrip" enables any record to be these quality features: exclusive picked up with ease and firmly "golden gap" of held without Monaural Tape 80 microinches for performance at PA leaving visible or audible narks, and with no track danger of slipping. The -like approaching performance at 7%2 IFS., %a Pliers design is such that the Miragrip can be Recorder, PLUS track; flush shield construction for greatest conveniently hum used with one hand, as negligible effort Is rejection and less poll piece wear; crosstalk fig- needed to hold the record absolutely Stereo Playback. ure of firm. The merit: 10 lb or better; colinearity and metal handles are chrome-plated and the straightness of gaps: within 5 millionths rubber gripping sleeves are of an available in a Records on all four inch. $30.00 list. variety of colors. The Miragrip is manufac- tracks separately. tured by Clarovox Products of 4 -track erase head erases one track at Also Coventry, Eng., available: Model 9QE3 - and is distributed exclusively In the United a time without affecting other record- %4 track erase head. $14.00 list States by Ereona Corporation, 16 W. 46th St., ings on the same tape. New York Tell us what model you have, 30. N. Y. User net price, $4.95. 17 hrs. of recording on one reel of tape. and we'll let you know what Plays back all stereo or monaural tapes. head will modernize or convert See your dealer or write to: your recorder to stereo. Robins Tape and Record Care TAN DBERG Accessories are available at high fidelity dealers everywhere, or write for FREE catalog. 8 Third Avenue, Pelham, N. Y. Canadian Agents: Engineering Sound Systems LN., 167 Kipling Avenue ROBINS INDUSTRIES CORP. South, Toronto 1e, Ontario, Canada 36-27 Prince Street, Flushing 54, N. Y. Clike, 245 W. Osborne Rd., Ne. Vancouver Circle 111A I,C., Canada Circle 111B AUDIO AUGUST, 1959 111 CLASSIFIED

Rates: l0c per word per Insertion ter nonoemutrelai advertisements; 251 per word for commercial advr tlsements. Rates are net, and no discounts will be allowed. Copy meet lie ateompanled by remittance I. full, and mast math the New York Ali by the first of the month preceding the date et Issm.

ARKAT CS -28

STEREO AMP /PRE -AMP TRADE UP TO STEREO : Largest selection of new, used Hi -Fi components. Professional COMPLETE service facilities available. Write Audio Ex- CONTROL CENTER change, Dept. AE, for trading information. 153.21 Hillside Ave., Jamaica 32, N. Y. Plains, Man- full 26 watts stereo or monaural. 60 watts peak 14 watts IWO Branches in Brooklyn, White channel reverse stereo balance control two-channel gill hasset. control lull range biss and treble controls IM distortion, 4 to 1 harmonic distortion, 1% 30.20.000 coo dual preamp 2V REPAIRED output jacks speaker outputs. 4. 0. 16. 32 ohms responve, "FLEETWOODfS HIGH FIDELITY SPEAKERS 2040.000 cps puth -pull Elle Williamson circuit. e CONRAC Amprite Speaker Service 44,-r,8 7, N. Y. BA 7 -2580 Wired and tested $99.95 Easy -to-build Kit High Quality TI' Choaaia. The Fleetwood 70 Vesey St., New York da Vinci" is a wall- or bookshelf -mounting ,s ARKAY ST -11 AM -FM 21 -1n. TV receiver with remarkable audio and ENJOY PLEASANT SURPRISES? Then STEREO TUNER performance. It Is designed to permit write us before you purchase any hi -fi. You'll visual savings. Key Elec- Here. for the first time, Is an AM. picture framing. Installed in a wall the da be glad you did. Unusual FM STEREO Tuner within the tronics, 120 Liberty St., New York 6, N. Y. audiophile. Unmatched by Vinci takes on the appearance of any picture of every The EVergreen 4.6071. urn s costing twice me price, the one might choose to hang in the home. aril is two distinct receivers In Fleetwood remote- control tuning unit pro- one featuring 4 vvl for dD quieting. Variable AK. singe front neces- WRITE for confidential money -saving prices panel switch controls AM, FM or sTEaEO selection. vides, at viewing distance, every control ,t ( on Hi- Fidelity amplifiers, tuners, speak- caved and tested $74.50 Easy-to -build Kit $49.95 sary for tuning television -on /of /volume. your brightness, con- ers, tape recorders. Individual quotations channel selector /fine tuning, only; no catalogs. ,1E Ychange, and Separate cathode fol- trast, definition. AR, 2375 E. 65th StCBro1 keld34,yn lowers are provided for audio and vido cir- 40 feet of cable. the cuits. Supplied with crossover networks. 118 may be used at any practical dis- INDUCTORS for fi remote unit types in stock. Send for brochure. C & M Coils, tance from the receiver. The Fleetwood da N. W., Ala. -neck 3016 Holmes Avenue, Huntsville, ARKAY SP -6 STEREO Vinci uses a special 21-in. 110 -deg. short ARKAY SPA -55 -all set CONTROL CENTER picture tube which permits an over AMP UNUSUAL VALUES. Hi -fi components, STEREO pramap WIM only 14 ins. A high- fidelity audio Versatile stereo depth of tapes, and tape recorders. Send for package Two 27 dual inputs and outputs. RMN channel affords faithful reproduction of the M41 amplifiers fori stereos filters, reverse position, bal. quotations. Stereo Center, 18 W. 37th St., am- Two separate BSI asm55 watt monaural ance control. Less covet. TV FM -sound transmission. N. Y. C. plifier. $6495 audio outputs are provided -one for connec- E fiueruild Kit $6495 Easy- o-buiid Kit$3995 connection tion to a loudspeaker, the other for Custom and rested $79.95 Wired and tested $62.95 music system. Conran, Inc.. CROSSOVER NETWORK KITS. to a high -fidelity and contract coil winding. Write Watson In- See and hear ARKAY Kits at your deafer. Glendora, Calif. User net price, Including California. unit, dustries, 110 Mildred, Venice, FREE! Stereo booklet and catalog. Write Dept. A 21 -in. picture tube and remote control All prices 5% higher west of Mlsslsslpel $399.00 SELL : Pilot SP -125 stereo preamp, $85 ; 800 chassis and remote unit $299.50 G. E. stereo cartridge. $14 ; Altec 039A micro- 810B self -contained chassis 249.50 phone, $55. Jac Holzman, 115 W. 16th St., 88 -06 van Wyck Expressway Richmond Hill 18. N.Y. N. Y. C., AL 5-3958. Circle 112A DEXTRAFIX CONCERTONE 61K monophonic record/ less than a year, in excellent Is called the playback, used Tone -Arms Control. This device condition. With 2 101/2 -in. reels, $430. Robert "Dextrafix" and is suitable for virtually all Baum, 435 Summit St., Lemoyne, Pa. types of independent tone arms used In con- IF YOU ARE MOVING SELL : Pentrol T-90 "Pacemaker" tape Please notify our Circulation Department recorder, new condition, $65 ; Acrosound 60- weeks In advance. The Post Office watt amplifier, $55 Garrard record changer, at least 5 V. R. Hein, 418 forward magazines sent to wrens with Pickering cartridge, $25. does not Gregory. Rockford. Illinois. destinations unless you pay additional pest. age, and we can NOT duplicate copies sent to you once. To save yourself, us, and the WANTED: Altec Lansing speaker system, with William S. your old address and your new address. model 820 C. Communicate Cooke, 403 Grandview Ave., Pitman, N. J. Post Office a headache, won't you please cooperate? When notifying us, please give FOR SALE : Mixing panel, custom made, six- position, two microphone inputs, four high - Circulation Department level inputs, two of which are bridging. Cinema RADIO MAGAZINES, INC. amplifiers, separate power supply, rack- mount- x IOs steel panel. Excel- P. 0. Box 629, Mineola, N. Y. ing, 19" /s" stainless lent condition. $500. A. C. Smrhn, 12 Mona - tainview Drive, Mountainside, N. J. CASH for used 401A Ampex - also trade 400A 1/2-track for full. Peter J. Helfrich, R. D. #1, Wescoessille, Pa.

PURITY OF SOUND! WANTED: Presto 16 -ohm 1 -D disc cutters. SMOOTHER OUTPUT! State condition and best price. 612 40th St. N.E., Cedar Rapids, Iowa. Audiofelt glued inside your stereo or hi -fi speaker enclosure Standard AA -903 amplifier and resonances and standing waves FOR SALE: Pilot corrects cabinet radiation, spurious preamp and Garrard RC -80 changer with which distort sound. G. E. magnetic cartridge (diamond stylus) and Formica base, $60 plus shipping. AU- Audiofelt is Developed specifically for enclosure damping, Standard DIO, Box CH -I, P. O. Box 629, Mineola, you full, natural N. Y. easy to apply and will last the life of your set. It gives sound free from coloration. WANTED: McIntosh amplifiers, type 50W2, in good condition. Bell Sound Stu- Cal.; York Write or phone Standard Felt Co., 29 S. Palm Ave., Alhambra, dios Inc., 237 West 54th St., New 231 S. Green St., Chicago 7, III.; 19, N. Y. 114 E. 25th St., New York 10, N. Y.; 693 Mission St., San Francisco 5, Cal. POSITION OPEN for audio -oriented electronic engineer or superior technician in New York recording studio. Call JUdeon 2-8815. Circle 1126 AUDIO AUGUST, 1959 112 PROFESSIONAL DIRECTORY junction with high- fidelity turntables. It is also useful with changers where it is desired to use the tone arm manually. Dextrafix acts as a safeguard against tone arm accidents which- ordinarily result in damage to records. stylus and cartridge. It is used to lower the cartridge into the record lend -in groove gently and accurately. At the end of play, or at any desired point on the record, it may be used to lift the stylus. The stylus cannot touch the record or table until the lift bar 1a lowered for the next play. Installation can be made in minutes. The Dextraflx is a most useful device. affording music lovers the same means for preserving their records employed Stops record damage! by most broadcast stations, Dexter Chemical Corporation, 845 Edgewater Rond, New York, Do you know all your records contain dust in America's foremost N. Y. User net prier, $4.05. every inch of groove? This unretouched photo- high performance FM KINEMATIX micrograph, courtesy of Wireless World (London), Stereo Balmier .lfcfer. Designed to assure shows how much is removed by one broadband Yagi optimum sound balance of stereophonic use of the ESL Dust Bug. If not removed, these speaker systems, this instrument Is intended strictly for home use. and once installed particles cause noise (especially on stereo Get more good music stations requires no further adjustment or manual records), operation. The attractively finished natural and also inflict permanent damage with your FM tuner. Improved wood case houses a single easy -to -read meter upon valuable records and styli. sensitivity increases signal strength and minimizes fading, The only safe, effective method of cleaning distortion and background noise. records is the ESL Dust Bug, acclaimed by more than 200,000 delighted users throughout the To be fully informed, world. It's easy, too -- it cleans automatically send 25e for book while the record is being played. Only $5.75 "Theme And Varia- complete (record changer model only $4.75), tions" by L. F. B. Carini FOR LISTENING AT ITS BEST and containing FM Station Directory. Electro -Sonic which Is connected to amplifier output termi- Laboratories, Inc. nals. The user simply- adjusts his volume APPARATUS DEVELOPMENT CO. Dept A 35 -54 36th St Long Island controls until the indicator on the meter is City 6,NY Wethersfield centered, thus assuring accurate stereo 9, Connecticut bal- Circle 113A ance. On the back of the meter housing are two volume controls Circle 113C which permit the user to purposely unbalance the stereo channels to compensate Fastest, Easiest Way To Learn All About for acoustic problems or off- center Audio seating arrangements. Sinematix, NEW Rider "Picture- Book" Course Inc.. 1616 N. Damen Ave., Chicago 22, Ill. User net price, FOR INTEGRITY IN MUSIC $14.11.5. BASIC AUDIO ~.THERE IS NOTHING FINER by Norman H. Crowhurst PHONO PICKUPS AND ARMS THAN A STROMBERG-CARLSON The Rider "picture- book" approach has made many technical subjects understandable to many hundreds of thousands of people. Now, everything 9K fuie sep less,:lie4 9d ü e about sound and audio reproduction crystal- is made clear. If hi -fi is your interest -or if you work with tape recorders of -or the broad subject sound reproduction interests you, -or if you assemble your hi -fi equipment "package" or buy a complete -you must read BASIC AUDIO. 7 O., 7. Z Ea 0") Li.. If you already -this own sound reproducing equipment special "picture- book" course will give you an all- around background on all the important nIt sound details of reproduction. It will enable you to the recording tape most from your equipment. get You can learn easily, rapidly You at very low cost. build your knowledge step -by-step. There's $1.19 "STEREO 60" one idea and one specially prepared illustration 1200 ft.; 7 guaranteed splice -free DUAL - CHANNEL AMPLIFIER per page. More than 400 illustrations "- mum understanding. for maxi- 1800 ft.; 7" . . $1.89. Enclose 10t for each reel to cover postage and handling. Beyond knowledge electricity vl,no previous lct on c experen a is needed Here are performance to get the maximum from this course. Whatever and control features electronics circuit theory entire is required to make the found ogly in amplifiers much higher in panorama of sound reproduction and re- cording visible to you is provided. price. Some of these are: each amplifier This Rider "picture- book" audio course is com- on a single chassis provides 30 Stromberg- pletely different from anything that has ever been presented. We guarantee your satisfaction. SOUND CORPORATION Carlson watts* of clean balanced power; #201. 3 vola., soft 820 W. OLYMPIC BLVD., LOS ANGELES 15, CALIF. covers . . . 88.70 per set exclusive Stereo Tone Balance Signal; chan- At your jobber or book store, or order direct A8 Circle 113F nel reverse John F. Rider Publisher, switch; separate volume, bass Inc., 116 W. 14th St., N. Y. 11 In Canada; Charles W. Pointon, b Aiuna Ave. Toronto and treble controls on each channel; master Circle 113D CANADA gain control. Price $169.95 (Audiophile High Fidelity Equipment Net, Zone 1). Your dealer is listed in the Complete Lines Complete Service yellow pages or write for specifications. HI -FI Records - Components deliberately LOOK and Accessories 'Our conservative ratings exceed published no further . If you're specifications, bused on ASRE measurement procedures. searching for hl -fl savings. Writs n your movies- moms now.. &LECTROTO10E STROMBERG -CARLSON Key Electronics Comma, GENERAL DYNAMICS 128-8 Lanny It, N.Y. L, .Y. SOUND SYSTEMS 1418 N. Goodman Street Rochester 3, N.Y. ev 4-on 126 DUNDAS ST. WEST, TORONTO, CANADA Circle 113E Circle 1130 Circle 113B

AUDIO AUGUST, 1959 113 ADVERTISING INDEX

Acoustic Research, Inc. 14 ... more cabinet Acro Products Company 94 Allied Radio Corp. 114 OUT Ampex Corporation 33, 34, 65 for your money CHECK Apparatus Development Co. 113 RECORDER Arkay 112 YOUR TAPE Atlas Sound Corp. 106 Audio Bookshelf 108 ON THE SPOT: Audio Fidelity Inc. 87 Audiogersh Corp. 6 Audio Tech Laboratory 96 Soundcraft's MAGNA -SEE Kit lets you Belden 7 Bell Telephone Laboratories 20 see the sound on your tape Best of Audio 4, 5 Bogen -Presto Company 49 MIDLAND high fidelity enclosures are Head Bozak 55 designed by acoustical experts. Chocks for: Head Alignment 90 Care- Bradford Audio Corp. fully controlled mass production Track placement and balance British Industries Corporation facing p 1, 3 wear techniques and over 25 years of ex- Contains: % pint CBS Electronics, A Division of Columbia perience as manufacturers of fine Magna -See Solution Broadcasting System, Inc. 107 furniture keep prices Classified 112 low without Plastic bath Connoisseur 102 sacrificing quality. Interior designs Eye -piece magnifier Concrac, Inc. 101 for any hi -fi problem, monophonic Pressure -sensitive Continental Felt Co. 27 or stereo. See them at your local Cosmos Industries, Inc. 43 tape 5 glass slides high fidelity showroom.

for permanent copies Dexter Chemical Corp. - 89 of your developed Dynaco, Inc. 66 track, and complete EICO 13 MIDLAND instructions. Electronic Organ Arts, Inc. 114 Makes editing easier Electro-Sonic Laboratories, Inc. 113 Electro- Voice, Inc. Cov. IV MIDLAND FURNITURE CORP. . -.more exact. 113 For free MAGNA-SEE Electro -Voice Sound Systems Ercona 102 8A, Lisbon, N. H. brochure, write Corporation Oep't Fairchild Recording Equipment Please send FREE illustrated catalogue of Corporation 16 enclosures. Fisher Radio Corporation 59 MIDLAND high fidelity Frazier International Electronics ,sounocaaFr.. Name Corporation 105 PASTURE ROAD. DANBURY, CONNECTICUT GREAT Fukuin Electric (Pioneer) 31 Address West Coast: 342 N. La Brea., Los Angeles 96, Calif. Electric 29, 53 Road, Toronto 9, Ont. Canada General City Zone State Canada: 700 Weston Gotham Audio Sales Co., Inc. 60, 61 Circle 114A Grado Laboratories 94 Gray High Fidelity Division .... Coy. III, 91 Circle 114C Hartley Products Company 95 Heath Company 8 -11 JansZen Loudspeakers 99 Jensen Manufacturing Company 39 Key Electronics 113 ELECTRONIC Kierulff Sound Corporation 113 Kingdom Products Ltd. 107 ORGAN KLH Research & Development Corporation 100 for your ALLIED'S SEND FOR Lansing, James B., Sound, Inc. 51 HOME! Lesa, Electrophono Cr Parts Corp. 15 tEW- a" ALLIED'S Marantz Company 92 BUILD -IT- Midland Furniture Corporation 114 BARGAIN Neshaminy Electronics Corp. 99 ,1 0110011 r YOURSELF Newcomb Audio Products Co. 17 _ SUPPLEMENT North American Philips Co., Inc. 62 ORRadio Industries, Inc. 104 SAVE! Paco Electronics Co., Inc. 63 Now you can own a professional electronic Pickering Cr Company 19 Pilot Radio Corporation 45 organ and save up to 50% on an easy Precise Development Corp. 57 you -build plan The world famous EVER! Save most pay -as- ... BIGGEST VALUES Professional Directory 113 14 models from the on Stereo hi -fi. See top buys in Allied - ARTISAN ORGAN-in recommended complete systems, Radio Corp. of America Coy. II popular 2- manual Home entertainment style compo- Radio Shack Corporation 93 to the majestic 4-manual Theatre and Church KNIGHT quality Stereo Reeves 114 Soundcraft Corp. style is now available in kit form. Simple step - nents, and KNIGHT -KIT build - 113 Rider, John F., Publisher, Inc. and your -own Stereo. Hundreds of values Rigo Enterprises, Inc. 35, 103 by -step instructions, pictorial diagrams in famous name amplifiers, tuners, Roberts Electronics, Inc. 2 schematics make this an ideal sparetime changers, speakers, accessories -as Robins Industries Corp. 11 1 project for anyone. well as recorders, P.A. systems, test Rockbar Corporation 25 FREE LITERATURE on REQUEST instruments and electronic supplies. 84, 85 Sargent Rayment Co. you purchase Send for your FREE Allied Supple- Schober Organ Corporation 106 Get the Artisan Story before ment packed with bargains and new Scott, H. H., Inc. 83 any Organ. Kit or commercial model. products. Save as never before! Sherwood Electronics Laboratories 1 47 Shure Brothers, Inc. ARTISAN ,.a New Home of Standard Felt Co. 112 ALLIED RADIO Stromberg-Carlson, A Division of General MUSIC HALL ARTISAN ORGANS Dynamics Corporation 113 SUPPLEME Studio Supply Co. 104 ORGAN ALLIED RADIO, Dept. 146 -He KITS 100 N. Western Ave., Chicago SO, 111. Tandberg 111 and Tannoy 102 185 COMPONENTS Send FREE Allied Supplement No. Thorens 97 Trans -World Electronics 98 Name Tung -Sol 4 ELECTRONIC 88, 109 Address University Loudspeakers, Inc. ORGAN ARTS, INC. Viking of Minneapolis 41 4949 YORK BLVD., Dept. A -8 zone State LCity LOS ANGELES 42, CALIF. Weather Industries 64 J Circle 114D Circle 1148 AUDIO AUGUST, 1959 114 START YOUR HIGH FIDELITY SYSTEM

WITH A GRAY COMPONENT wsamaZEo

...GRAY COMPONENTS for expert workmanship at low cost to you

GRAY Hysteresis - GRAY Custom DeLuxe turntable, arm and base Synchronous Turntable Kit Factory assembled components Precision engineered parts. that give you all the extras you Balanced for both stereo need for the most complex sys- and monophonic use. 331/2 tem. RPM belt drive. 33 H (Hysteresis- Synchronous) HSK -33 turntable .. $49.50 Turntable $79.95 SAK-12 tone arm.. 23.95 212 SX 12" arm 34.00 TBA base 17.95 33 C Wood Base 23.95 GRAY Tone Arm Kit GRAY Micro - Outstanding features such Balanced Pressure Gauge as linear fluid damping, Indicates pressure on record quick- change cartridge surface so that adjustments slide, adjustable static can be made for proper track- ' balance, and versatile wir- ing. A true balance without ing for all cartridges makes SAK -12 tone arm your best buy. springs. SAK -12 12" arm kit $23.95 PG 200 gauge $2.50

Visit your friendly quality Gray dealer for a full demonstration. Write to us for complete literature.

our 67th year in communications .. . High Fidelity Division GR YDEPT. 6 16 ARBOR STREET, HARTFORD 1, CONN Ooûooiti»tfie 1//1 ...WITH 2 -WAY WIDE -RANGE

MUSICASTER - - all- weather high -fidelity speaker system

Now you can very easily set up a permanent or portable outdoor extension of your high -fidelity music system ... for relaxed enjoyment. Take the MUSICASTER to the patio, or pool ... and treat yourself, your family, your guests to the pleasure of a full concert or background music ... or even the ball game.

% Unique design of this compact, integrated loud- speaker system assures superb musical balance and clarity. Exceptional bass response is achieved through the back- loaded folded horn. High frequencies are smoothly and efficiently radiated from the exclusive E -V Radax dual - r"' cone speaker. Wide projection angle simplifies placement of the MUSICASTER for complete listening coverage.

All -weather performance is guaranteed by special silicon - treatment of the cone assembly. The speaker is fully protected by the rugged diecast aluminum housing ... handsomely fin- ished in Mesa Tan baked enamel. You can set the MUSICASTER anywhere on its built -in rubber feet. Use the mounting bracket as a convenient carrying handle.

DOUBLE YOUR FUN WITH STEREO. You can add the ex- citement of stereo sound outdoors with a second MUSICASTER. Ideal combination of wide -range response and wide -angle dispersion gives you the startling realism of 3- dimensional reproduction.

E -V MUSICASTER High -Fidelity Speaker System. Response: 60- 13,000 cps. Dispersion: 120 °. Impedance: 8 ohms. Power handling capacity: 30 watts. Size: 21'/," h. x 21%" w. x 8'/," d. Net wt. 23 lbs. List Price, $80. Net Price, $48.

Accessory Model MB -1 Surface Mounting Bracket. For neat, unob- trusive installation on flat wall. List Price, $4.50. Net Price, $2.70

See it ... Hear i t ... En j o y it ... on Money -Back Guarantee

At Your E-V Franchised High -Fidelity Dealer -or write for Free Bulletin No. 258A to Dept. 89 -A ELECTRO -VOICE, INC. BUCHANAN, MICHIGAN

Research- Engineered High-Fidelity Speaker Systems, Phono -Cartridges, Microphones, Sound Projectors, Communications Equipment, Marine Instruments, and other Electro- Acoustic Products.