MARCH, 1960 50¢
", I • "Balanced for versatility" best describes RCA's hi-fi tube line: Balanced for power. .. gain ... sensitivity BALANCED versatile enough for every hi-fi application from preamplifier to power amplifier-in mono and stereo-and in any power range! • Never have so many features been incorporated in only four tube types: RCA-7025- LINE FOR high-mu twin triode . .. a "must" for extremely low-noise, low-hum preamplifiers; RCA-7199-sharp cutoff BALANCED pentode and medium-mu triode in one envelope. Here's versatility for those low level stages; RCA-6973-a miniature beam power tube that makes amplifiers compact and powerful. A pair in class AB!> delivers up to DESIGN .. ! 20 watts! And RCA-7027-A-glass-octal beam power tube offers power deluxe-up to 76 watts from a pair in class AB] with only 2 % distortion! • Specify RCA's balanced hi-fi line for your new designs, and use the proven performance of RCA tubes to insure the success of your product. Ask your RCA Field Representative for details. For technical data, write RCA Com mercial Engineering, Section C-91 -DE, Harrison, N. J.
field offices EAS T: 744 Broad Street Newark 2, N. J. D HUmboldt 5·3900 MIDWEST: Suite 1154, Merchandise Mart Plaza Chicago 54, III. D WHitehall 4·2900 WEST: 6355 E. Washington Blvd. los Angeles 22, Calif. D RAymond 3·8361 MARCH, 1960 VOL. 44, No. 3
Successor to RADIO, Est. 1917.
INCINEERINC HUSIC SOUND REPIIODUCTION c. .G. McProud, Editor and Publisher Henry A. Schober, Business Manager Harrie K. Richardson, Associate Editor Linda Sueskind, Assistant Editor Janet M. Durgin, Production Manager Edgar E. Newman, Circulation Director
Sanford L. Call1l, Advertising Director Midwest Representative- W. A. Cook and Associate$ 161 East Grand Ave., Chicago 11, ill. Well Coast Representative- lame. C. Galloway 65~5 Wilshire Boulevard, Los Arigele$ 48, Calif.
CONTENTS
Audioclinic-Jo se ph Giovanelli 2 Letters ...... 6 Light Listening- Chestm' Santon 10 Audioman No. 6- RobM·t F. McDonald 12 Audio ETC- Edwa1'd l 'atnall Canby 14 Editor's Review 16 An Adjustable Power Supply-John P. W entworth 19 The Wood Panel That Talks- A b1'aham B. Cohen 20 Audio Engineering Society Convention 24 Hi-Fi Speaker System with a Roof- Cove1' St01'y 26 Tape Guide-Maintaining Frequency Response in Recorders- H M'man BUI'stein-In Two Pa1·ts, Pa1·t I ...... 28 Output Transformers-Jan~e s Moi1'-In Two Pa1·ts, Pa1·t II 34 Equipment Profile-Standard Measurements, Scott 299 46 Record Revue- Edwa1'd Tatnall Canby ...... 48 Jazz and All That-Cha1'les A. Robe1·tson 54 About Music- H a1'old LatV1'ence 60 New Products 62 New Literature 64 Advertising Index 76
COVER PHOTO - Stereo loudspeaker system in the home of Dr. John K. Hilliard, Vice President and Director of Advanced Engineering, Altec Lansing Corporation. For a full descr iption of this installation, tUl'l1 to page 26.
AUDIO (title registered U. S. Pat. Olr. ) Is published monthly by Radio Magazines, Inc., HenrY A. Schober, President; C. O. McProud, Secretary. Executive and Editorial Omce., 204 Front St., Mineola, N. Y. Subscrlptl.on rates---U. S. POIIBOSSlon., Canada and Mexico, $4.00 Cor one year, $1.00 Cor two years, all other countries, $5.00 per year. Single copies 500. Printed In U.S.A. at Lanca.ter, Pa. All rights reserved. Entire contents copyrighted 1960 by Radio Magazines. Inc. Entered as Second Clas. Matter February 9, 1950 at the· Po,t' Omee, Lancaster, Po: under tbe act oC March 3, 1879. RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y. P08bnaster: Send Form 3579 to AUDIO, P. O. Box 629, Mineola, N. Y. '. FOR COMPLETE SPECIFICATIONS WRITE DEPT,
AUD'IO • . MARCH, 1960 1 AUDIOclinic -
JOSEPH GIOVANELLI*
Trouble with a Stereo Amplifier strength that it can modulate the B supply common to both amplifier units. It SOlinds Q. A friend recently purchased a dual very much as though the resistively loaded 20-watt stereo amplifier-preamplifier ~tnit, channel becomes unstable with a purely re stereo cartridge, turntab'le and stereo arm, sistive load. Apparently a slight amount and an AR-2 speaker. H e plans to buy the of inductance is needed. You could try to second speaker when he is again in the load the amplifier channel with this same money. resistor with a 2.5 mh choke in series or 1. In the absence of a second speaker, perhaps in parallel with it. This is not AeRO'S STEREO PRE·AMPLIfIER how should the second amplifier be loaded? guaranteed, but it does sound reasonable. INPUTS each channel I added an 8-ohm, 20-watt resistor but de Of course, there is one obvious thing to do, • Mlgnetic (Turntlble & Chlneer) Equllized 78, LP, tected an irregularity in operation which and that is simply to pull out the driver RIM "CZisappeared as soon as I connected a bor • Crystll/ceramic (switched in mae. Inpull Sensitiv· tube for the unused stage. This 'should not ity for 1.5V out low level 2 MV. Hieh level 20 MV. "owed second speaker. With the Tesistor be done unless you are sure that the suc • Tape Head Equalized NARTB Sensitivity 2 MV load the pilot light indicated a slow, pulsed ceeding stages are not direct-coupled to the • FM • AM • 'FM Multiplex • Tlpe Head dimming, and the driver tube in that chan • Microphone (switched into one channel for announc· one which has been disabled. The reason nel gave fOTth with a momentary burs~ of ine, faded in or out with bilance control) " 4 that I did not say that you should take all OUTPUTS 2 Ampl., 2 Tape, 3rd Chlnnel light , accompanie by a loud, trans tent of your tubes in the unused stage out of INPUT SELECTOR ' (8 positip~) 78, LP, RIMl, RIAA2 Tape Head, FM-AM, FM Multiplex & Aux. sound in the speaker. the circuit is that the power supply load OUTPUT SElECTOR 7 MODES (Check-A, Check-B, 2. Would it be feasible to connect a will change, and it is possible that the B Stereo, Stereo Reverse, Monaural A·B, Mon.ural A, small, inexpensive speaker to the second Monaural B) 6 panel lieht Matrix provides selection plus voltage will become excessive under Mode at a glance_ cliannel, with the balance turned way over this operating condition. If the balance CONTROLS Volume/loudness, Balance, Individual Bass to the AR-2? control is one which can vary the output & Treble for each channel 3. My friend wishes to use the dual 20 of either channel from full output straight SWITCHED EXTRAS effective each channel. Filters, watts to give 40 ~vatts playing 7nonophonic scratch and rumble • loudness • phasine • tape through to zero output, all you need do is input/monitor • mike dub records thTo~Lgh his single speake?". How to turn the balance control to the zero AC OUnETS 2 switched 2 direct can a stereo amplifier be strapped to a output position for the unused channel. ,TUBES 2 Type 7199 low noise pentode/triode. 2 Type single speaker? 2. Your second alternative is a good one. 7247 dual triode 4_ The a?nplifier oveTloads at low fre DIMENSIONS 4%H x 13% :'x~%..!> So long as you have the inexpensive speaker q~wncies ~vhen the gain control is in the connected to the second channel anyhow, loudness posilion and the bass is. turned why balance the system in favor of the f~Llly on, with the 10~Ldness control about AR-2t Suggest to your friend that he use a quarter on. Is this a normal result of the second speaker for monophonic listen such bass emphasis, and are not these two ing, even though it may not be a pe;fect controls (lo~Ldness, bass) normally so de match for the AR-2. Even a really mex s'igned that the amplifier is stable even dur pensive speaker can probably handle suffi ing ext?-eme opemUng conditions? D. R. H., cient wattage to permit an acceptable lis Rochester, N. Y. tening level. A. 1. Had you not beat me to it by 3. If your friend wishes to use his stereo running into trouble with the 8-ohm resis amplifier as a 40-watt monophonic· unit, AeRO'S STEREO 20·20 AMPLIfiER tor, I would have told you to load the un all he needs to do is to feed the signal into used channel resistively. Apparently that one channel, set the selector switch to the The ACROSOUND STEREO 20-20 completely meets the needs of the most exacting stereophile_ The STEREO channel does not like a resistive load. Since position which will feed that channel into 20-20 is a two-channel basic amplifier with common I do not have the circuit for your friend's both power amplifiers, and then strap the power supply, Rated output is 18 walts per channel at 1.5% 1M, 16 walts per chlnnel 0_5% 1M. For mono amplifier, I cannot be sure of some of the outputs of the two amplifier sections to aural use the channels can be paralleled to provide 36 points you have raised. You mentioned a gether. If the speaker to be used is an watts of clean power (72 watts on peaks) . The , ACROSOUND STEREO 20-20 Amplifier uses. new, self· pilot light, which I assume is in the chan 8-ohm unit, strap the two 8-ohm taps to balancing. Direct-coupled Circuit' combined with nel which you resistively loaded. It would gether and connect the speaker between Ultra-Linear connected output tubes for unparalleled stability and transient response. Each amplifier oper· be important to know in which section of these joined taps and common_ For safetY'1> ates under constant current conditions (pure class A), the circuit the light is located, and from sake, it might be a good idea to join the resulting in no cross talk between channels. Each channel lIlay be controlled with its individual level whence the source of the lighting voltage two commons together. This system, how control. Outputs of 4, 8, 16, 32 ohms (2, 4, 8, 16 comes_ You mentioned that, as the light ever, mayor may not prove satisfactory. ohms with channels in parallel) for maximum flexi brightens and dims, the speaker gives out bility with speaker combinations. Size: 7" x 10" X Your friend may again run into the same 5'1." high. Weight: 18 Ibs. with a transient sound. Are you saying that old instability problem which plagued him For 60 watt power In ,ach chann,1 amplifiers use 2 the speaker connected to the normally in section 1. This time, however, the in famous Aero Ultra Linear II Amplifiers. loaded "channel makes this sound' It ap stability may be noticed in both channels. Aero, eM first name in audio 1 pears that whatever is happening in this If each channel contained variable damp Hear it at your dealer now 1 resistively-loaded channel is of such ing, this can cause trouble. It is more than "ACRO PRODUCTS CO. Dept. AUD-3 likely that the instruction manual provided 369 Sburs une,- Pbiladelpbia 28. Pat * 3420 Newkirk Ave., Brooklyn 3, N. Y. with the unit will show the best manner
2 AUDIO • MARCH , 1960 ~irst Repeat of our Announcement (in December 1958 ) of the
MODEL 4HF This precision single play unit was acclaimed instantly, and it has been in such demand during these 16 months that we have deliberately withheld any further advertisements. We are now repeating our original announcement for the benefit of those who have entered the market ' during this period. Model 4HF is a four-speed deluxe transcription turntable and transcription tone arm, combining in one unit the distinguishing qualities of both. Already mounted on a single unit plate for simplest installation, the 4HF forms a superb instrument. complete at only
Push-button system for auto-trip mechanism. A touch of the finger disen gages the tone arm comoletely from the player mechanism, and arm becomes _~~~ ______independent as if mounted separately. I~,,-~~ ______Auxiliary stop mechanism built into tone arm rest. Unit shuts off when the arm is placed on rest • ...... -.:, <::l""""'------Professional transcription tone arm newly designed with plug-in universal shell to take all stereo and monaural cartridges. Simple, accurate, weight adjustment. ______Four speed unit with variable + or _ speed adjustment on all four speeds. Heavy duty turntable, 12 inch diameter; heavy weight steel with rubber • ~~:::::::::::~2::::======: tractionNew center mat. spindle housing with pressure lubricating system, for long life and dead quiet operation.
There's a Garrard for every high fidelity system. Fully wired for Monaural and Stereo records. New Comparator Guide - FREE Garrard Sales Corporation, Dept. GD.IO Port Washington, New yorlt. " . • . ' . """;; ~'. I /.~ e~.' • Please send your new comparator pfde ~. ~~ ~ -' , . '~~'" . , which compares all Garrard plqers and their lUlvanced features. ~ Namae ______· 1IC121/D TPA/12 301 ModolT/D 011 ... Intennlx st,," TranscrIption MlnUlI ~ Chanpr Chanpr Tont Ann Tumtable PlQ" AdmwL· ______~ ____ - - $4Z.IO $11.10 ".110 ".110 ".00 City.:..-.______
GARRARD SALES CORPORATION, PORT WASHINGTON, N. Y. - Zm&e ____~Sma~~ ______Conadlcm InquirIes to Chas. W. PaInton, ltd• • 6 Alcina Ave., Toronto T,rrllorles other than U.s.A. ond Canodo to Garrard Engln ••rlng & Mfg. Co., ltd., Swlndon, Wilts., England for connecting the pOwer amplifiers for monophonic use. 4. The main consideration with any am Whats the pliiier designed for high fidelity listening is that it sound good. Very few people will use their equipment with the bass turned to maximum boost. The loudness control shoud not be considered as a tone control, but as a compensation for cJlanges in frequency response of the human ear with corresponding changes in volume. As the latest score loudness control is put further and further into the circuit, the over-all vOlume of sound is decreased. Therefore, even if a listener does wish to use his equipment with maximum bass boost, the lOudness control should not cause distortion. The problem begins to appear when the volume and loudness can be operated separately. Under these circumstances it is possible for the on cartridges? operator to turn the volume up as he turns the loudness into the circuit, which will maintain the signal level at the same point and will cause a boomy kind of reproduc tion not intended by the designer of the equipment. With the bass fully boosted and ceramic cartridge the loudness and volume controls operated ST was invented as just described, the middle and high fre quencies will be sharply attenuated, and 1 by Sonotone ... the ampliiier will appear to be playing quite sOftly. Bass never Sounds very loud to most of us. The middle and higher fre quencies are the ones wh ich tell us how loud a sound is. All of this has been said to point out that you may, under the condi years ago. tions, be driving your amplifier to the 20- Today, over ... watt limit and beyond, and not even know 13 it because the sound is not loud. The am plifier does not know that the listener hears a fairly soft sound. All it knows is that the output tubes are being driven beyond their ratings, and that the output transformer is being saturated. This contributes to dis different manufacturers tortion. I think this is the more likely situ- ation, rather than there ~eing a design 65 have specified Sonotone for ... flaw in the amplifier. Preamplifier COupling Circuits Q. As a dedicated circuit butcher, I am familiar with the Pl'oblems entailed in models of high-quality selecting values Of coupling capacitors for phonographs. the power output stage. Howevel', l'egard_ ing the preamplifier stages, I am at a loss. 662 Altogether over ... Could you suggest a practical appl'oach to this problem? What trM£bles Would I run into by using a O.l-ILf COupling capacitor in place Of a O.Ol-ILI capacitor in a pre Sonotone Ceramic amplifier stage? I know that time constants are involved. In gOing through standard Cartridges have been used circuits, I notice that COupling capacitors in lOW-level stages are small but increase for original and as the circuit progresses toward the output 9,000.000 replacement purposes. stage. Allan M. Palmer, Brooklyn, N. Y. ('Nuff said!) A. The reason for small values of cou pling capacitors in lOW-level stages, as you have guessed, is a matter of their time con stants. We are not as concerned with this problem in succeeding stages because of the lower gain of the tube being by the 'c Sonotone o capacitor. As a general rule, the lower the ®R gain of the tube, the more its control grid El ectronic Applications DivIsIo n; Dept. C26.30 p. can be Swung without cutting the tube off. High-mutubes have a relatively small grid ELMSFORD,NEWYORK voltage swing. Let us aSSUllle that we have In Canada, contact Atlas Radio Corp., Ltd., Toronto a large coupling capacitor and a large grid Leading makers of fine ceramic cartridges, speakers, tt1 phones, electrOnic tu~• . resistor. connected to just such a high-mu icro tube. AssUllle also that a suddeu, low-fre- (Contim£ed on page 71)
AUDIO • MARCH, 1960 /' Unequalled Performance in a wide variety of units --ALTEC STEREOPHONIC - MONOPHONIC AMPLIFIERS -PREAMPLIFIERS
0) ~ 0)!:\ STEREO , cQ) Q})cQ)W AMPLIFIER-PREAMPLIFIER • Advanced engineering features make the 353A today's outstanding single stereo unit. • 100 watts peak stereo; 50 watts rms continuous • Two or three channel stereo • Dual mic inputs for stereo recording • 14 stereo or mono outputs, 6 stereo or mono inputs • Flexible controls for 13 separate stereo or mono conditions
Specifications: Power output: 100 watts stereo program peak power; 50 watts rms continuous stereo or mono • Rumble filter: 12 db per octave below 30 cps • Distortion: Less than 1% THD at 25 watts 1000 cps each channel; Less than 1% THD at 20 watts 30-15,000 cps each channel • Response: 20-20,000 cps at 25 watts, ± 1.0 db; 10-30,000 cps at 1 watt, ± 0.5 db • Noise level: Radio, tape, multiplex (250 mv signal): 82 db below 20 w output; Magnetic phono (5 mv signal) 60 db below 20 w output; Tape head (2_5 mv) 58 db below 20 w output • Dimensions: . 5'l's" H xiS" W x 111,4" D • Weight: 35 Ibs. approxima~ly • Price: $199.50
®~®£ MONO AMPLIFIER ®6J~£ STEREO Unexcelled purity and perfection POWER AMPLIFIER in performance. Distortion-free over entire audio range. Power This rugged power am tubes have 100 watt capacity. plifier packs two 100 watt (peak) channels in 70 v output for multiple speaker one package. 60 watts rms continuous, stereo or mono. installations. Ideal for public address systems or addi Independent level control for each channel. Five tion for full stereo. control switching 'permits use in nine different combi Specifications: Power output: 40 watts at less than 0.5% nations for stereo or mono. Speaker impedance is set THD • Response: ± 1 db 5-100,000 cps· Load impedance: 8, automatically for each channel. Unity damping factor. 16 ohms and 70 v • Output impedance: continuously adjustable Specifications: 200 watts stereo program peak power; 100 watts .14 to 7.5 times nominal load impedance on 8 to 16 ohm taps. each channel; 60 watts rms continuous stereo or mono· Response: Less than 10% of nominal load impedance on 70 v line tap· Noise ±1.0 db 10-100,000 cps· Gain: 66 db • Noise level: -40dbm, level: 40 dbm; 86 db below full output· Controls: gain control 85 db below full output· Distortion: Less than Vz% THD 40-15,000 RljRG control, power switch • Dimensions: 7" H x 9%" W x cps at 40 watts· Dimensions: 6Vz" H x 16ljz" W x 12Vz" D • 131,4" D • Weight: 27 Ibs. Price: $171.00 Weight: 38 Ibs .• Price: $270.00
6J6J~£ STEREO 6J6J®© MONO PREAMPLIFIER PREAMPLIFIER The ultimate in music This advanced stereo reproduction equipment. control system delivers Unique tape monitor func the high degree of per tion; separate controls to formance and flexibility vital to true stereo reproduc tion. Lighted, error-free push buttons control all input adjust high and low fre selection and on-off switching. Transistorized preamp quency recording. 25 input stages reduce hum and noise level. Ganged level crossovers; inputs for phono pickups, cartridges, tape, control maintains perfect stereo balance even during tuners, TV sound, mike. DC heater supply for tubes. volume changes. Specifications: Inputs: 3 high level; 2 low level • Outputs: Specifications: Channels: Two· Input: Total of 12-3 high level 2 - one main amp, one recorder· Gain: 60 db at 1 kc • Response: pair, 3 low level pair equalized for single or stereo reluctance pick 20-22,000 cps· Noise level: 95 db below 1.5 v output· Controls: ups, tape heads, or flat for microphones • Outputs: Total of 4- 7: switches for choice of inputs; separate volume, power, tape, 1 main output each channel, 1 recorder output each channel, inde bass and treble controls; 5 level controls • Power supply: self pendent of volume setting • Range: 20-22,000 cps • Dimensions: contained -117 V, 60 cycles· Dimensions : 4%" H x 13%" 4%" H x J21h" W x 6%" D· Weight: 6% Ibs •• Price: $189.00 W x 5%" D • Weight: 11 Ibs. Price: $147.00
~"'IIIPI!. ALlEC LANSING CORP., Dept. AD-3D Write for your free COpy of Altec's new product 1515 S. Manchester Ave., Anaheim, Calif. catalog for complete descriptions and specifications on all 161 Sixth Ave., New York 13, New York AZtec quality engineered Bound co'mponents. A Division of Ling-Altec Electronics, Inc.
AUDIO • MARCH, 1960 5 LETTERS Corrections Mrs. Hall's and Mr. Briggs' anaiyses, SIR: from simple computation show that the Regrettably, I made some errors in the average velocities of present day cone l!l0- manuscript and drawings for my article tions are so low that distortion due to the "Universal Feedback Amplifier Circuit," altcration in sound velocity appears to be which appeared in the January issue, and insignificant. , would appreciate your advising the readers First, I should like to point out that in of the following: the race for high-compliance suspensions In F.ig. 1, a 15-""""f capacitor should be and long cone excursions, we may soon >t see cone, motions of several inches. This G) .connected across the 240-k plate resistor, ... and the two 220-k grid resistors for the will . mean significant velocities relative to '"G) ... 5881's should be connected between the the velocity of sound in air. Also, what ~ coupling capacitors and the 10-k grid happens under certain transients or wave G) stopper resistors . forms with a steep rise where the velocity .:z over a portioJi: of the cycle may be 100 Q The word "reviewed," in the twelfth line of the second column on page 19 should times the integrated velocity of a full cycle. - be "renewed," and the "+" sign before The alteration in pitch is not deduced 5.28 """"f in the last formula in the second by the change of sound velocity relative to column of page 20 should be an "=" sign. a stationary cone, but the alteration is a Please advise those who have been so compound 'of the lower velocity wheu the kind as to write for reprints of this article cone is moving away from the listener, re that I have none, and suggest that they lated to the higher velocity when the cone order copies of the magazine from you. is moving toward the listener during the ARNOLD J. KAUDER, following half cycle. 448 N. LaJolla Ave., Doppler distortion is akin to turn table Los Angeles 48, California wow which the industiy attempts to hold (Mr. Dalzell also writes us again to say below 0.2 per cent. I grant that strict that he should have listed the P.I.V. for standards are necessary here because of the selenium rectifiers listed under Mis the rhythmic nature of turntable wow and cellaneous Data in the table at the top of its independence of signal frequencies. But page 21 of the December issue should be if we assume a cone having a peak-to-peak 600 volts instead of the 400' volts indi sinusoidal displacement of one inch at 40 c.ated. ED.) cps, then the cone will move axially 80 in. per second.. The variation of minimum to Loudspeaker Li nearity maximum sound velocity relative to a SIR: fixed listener is 0.6 per cent. For a sine Mr. Villchur, in an attempt to clarify wave of this frequency the maximum in some apparent misunderstandings about stantaneous velocity will be theoretically the functioning of acoustic suspensions (in 122 in. per second for some finite time' over the January issue) has unfortunately the center of the swing. With larger dis created additional misunderstanding about placements around the corner, or with the linearity differences between the iso high instantaneous velocities as in percus thermal and adiabatic process. sive sounds, square waves, and transients, . Mr. Villchur states that the non-linearity this variation can be much higher. III the pressure changes is characteristic It is the writer's belief, supported ,vith of the adiabatic process. The implication some experimental evidence, that Doppler is t~at th~ non-linearity is caused by the effects lasting only a few illilliseconds, due exponent III the gas equation PV1.4 =K. to the shifting and rapid interplay of fre He concludes that the gas equation be quencies and amplitudes, destroy the "re comes lineal' when the exponent becomes solving power" of the loudspeaker. It ex equal to 1.0, as in the constant-tempera plains in part why a bank of speakers ture (isothermal) process. possesses finer definition of the instru "Thus, even the tiny amount of distor ments in orchestral passages than a single tion associated :with air non-linearity is spea,ker delivering the same total acoustic not present ..." power. Or channelizing the frequency spec The gas equation is not a linear function trum into 2-way or 3-way speaker systems for a~y value of exponent. It is a power will likewise sound cleaner. Horn-type functIOn of the form, y = axn. When n is woofers are noted for minimum distortion negative, as it is in. the gas equation, the partly because they require minimum cone curves are hyperbolIc curves and there displacement for a given acoustic output fore, non-linear for all values of' n. The relative to a cone working directly on the point is that if one concedes the existence atmosphere. of non-linearities in the adiabatic process, The "resolving power" of a speaker, one must also concede non-linearities in when properly understood, could become a the .isothermal process. Distortionless op new measurable characteristic and I feel eratIOn cannot be claimed because of iso will be closely related to Doppler distortion. thermal compression inside of the box. Under complex frequencies at high levels JAlIfES F. NOVAK, Sr. Design Engineer we can expect an aggravation of short Jensen Manufacturing Co., ' period intermodulation distortion because 6601 S. Laramie Ave., of the varying cone velocity, some of this Chicago 38, Ill. generated acoustically in the atmosphere c--. and some in our hearing mechanism, all Doppler Effect contributing to acoustic debris. CD SIR: In our rapidly expanding art, speaker Your October, 1959, issue contained a diaphragm displacements of several inches c: letter by G. A. Briggs in which he at are a coming possibility. As a matter of tempts to lay to rest the Doppler super fact, the writer has designed and demon -- stition, particularly in view of the tech strated a speaker with a peak-to-peak dis OJ) nical articles by Mrs. Jane Hall and placement of three inches, with built-in Virginia Rettinger. restoring force, for the purposes of study c: =C) ~ Mr. Briggs is quite graceful in tipping ing Doppler distortion. his hat to the ladies and he writes with SAUL J . WHITE, Chief Engineer, ~ ~ considerable charm. But he fails to see Audax, Inc., E ahead or to carry his analysis to any 38-19 108th St., u -- depth. Corona 68, New York 6 AUDIO • MARCH , 1960 New Amplifiers
MORE OF THE BEST FROM tHE LEADER Heathkit, first in performance, quality and dependability, proudly - presents a host of new, outstanding do-it-yourself projects de signed, as always, to bring ·you the finest.in kit-form electronics.
FOR THE FINEST IN STEREO, , , 14/14 WATT STEREO AMPLIFIER KIT (SA-2) A complete dual channei amplifier/preamplifier combination, the new Heathkit SA-2, in one compact, . handsomely styled unit provides every modern feature required for superb stereo reproduction ... yet is priced well within your budget. ... Delivers 14 watts per channel stereo, or 28 watts total monophonic. Maximum flexibility is 'provided by the 6-position function switch which gives you instant selection of "Amp. A" or "Amp. B" for single channel monophonic; "Mono. A" or "Mono. B" for dual channel monophonic using both amplifiers and either preamp; and "Stereo" or "Stereo reverse". A four-position input selector switch provides choice of mag netic phono, crystal phono, tuner, and high level auxiliary input for tape recorder, TV, etc. The magnetic phono input is .RIAA equalized and features 3 mv sensitivity-adequate for the lowest output cartridges available today. Other features include a speaker phasing switch, two AC outlets for accessory equipment and hum 'balance controls in each channel. As beautiful as it is functional, the SA-2 will be a proud addition to your stereo sound system. Shpg. Wt. 23 lbs. SPECIFICATIONS-Power output: 14waUs per channel, "hi·fi"; 12 watts per channel, "professional"; 16 watts per channel, "utility". Power response: ± 1 db from 20 cps to 20 kc at 14 watts output. Total harmonic distortion: less than 2%. 30 cps to 15 kc at 14 watts output. 'ntermodulation distortion: less than 1% at 16 watts output using 60 cps and 6 kc signal mixed 4:1. Hum and noise: mag. phono input, 47 db below 14 watts; tuner and crystal' phono, 63 db below 14 watts. Controls: dual clutched vo lume; ganged bass, ganged treb le; 4-position selector; speaker phasing switch. Inputs: 4 stereo or 6 mono phonic ~ Outputs: 4, 6 and 16 ohms. Dimensions: 4,X" H. x 15" W. x 6" D.
GO STEREO FOR JUST $29,95 ECONOMY STEREO AMPLIFIER (SA·3) This amazing performer delivers more than enough power for pure, undistorted room-filling stereophonic sound at the lowest possible cost. Featuring 3 watts per stereo channel and 6 watts as a monophonic ampli fier, the SA-3 has been proven by exhaustive tests to be more than ade quate in volume for every listening taste. A tremendous buy at this low Heathkit price. Shpg. Wt. 13 lbs. SPECIFICATIONS-Power output: 3 watts per channel. Power response: ± 1 db from 50 cps, 20 kc at 3 watts out. Total harmonic distortion: less than 3%: 60 cps, 20 kc. Intermodulation distortion: less than 2% @ 3 watts output using 60 cycle & 6 kc signal mixed 4:1. Hum and noise: 65 db below fuO output. Controls: dual clutched vo lume; ganged treble, ganged bass; 7-position se lector; speaker phas ing switch; on-off switch. Inputs (each channel): tuner, crystal or ceramic phono. Outputs (each channel): 4, 8,16 ohms. Finish: black with gold trim. Dimensions: 12X" W. x 6Y.'" D. x 3)1.4''' H.
MORE STATIONS AND TRUE FM QUALITY ARE YOURS WITH THIS FINE TUNER KIT HIGH FIDELITY FM TUNER KIT (FM-4) This handsomely styled FM tuner features better than 2.5 microvolt sensitivity, automatic frequency control (AFC) with on-off switch, and prewired, pre aligned and pretested tuning unit. Clean chassis layout, pre aligned intermediate stage transformers and assembled tuning unit makes construction simple-guarantees top performance. Flywheel tuning and new soft, evenly-lighted dial scale provide smooth, effortless operation. Vinyl-clad case has black, simulated-leather texture with gold design and trim. Multiplex adapter output also provided. Shpg. Wt. 8 lbs. SPECIFICATIONS-Tuning range: 88 to 108 mc. Quieting sensitivity: 2.5 uv for 20 db of Qui eting. IF frequency: 10.7 mc. 'mage ratio: 45 db. AFC correction factor: 75 kc per volt. AM suppression: 25 db . Frequency response: ±2 db 20 to 20,000 cps. Harmonic distortion: less th an 1. 5%, 1100 uv, 400 cycles 100% modulation. Intermodulation distortion: less than 1%. 60 cycles and 6 kc mixed 4:1 1100 uv, 30% modulation. Antenna: 300 ohms. Output impedance: fiooohms (cathode fo llower). Output voltage: nomi nal .5 vo lt (with 30% modulation, 20 uv signal). Overall dimensions: 4X" H, x 13X" W. x 5)1" D.
AUDIO • MARCH, 1960 7 /
NOW-FOR THE FIRST TiME-EXCLUSIVELY FROM HEATH ACOUSTIC SUSPENSION New HI-FI SPEAKER SYSTEM KIT (AS-2) A revolutionary p.inciple in speaker design, the Acoustic Research speaker has been universally accepted as one of the most praiseworthy speaKer systems in the world of high fidelity sound reproduction. Heathkit is proud to be the sole kit licensee of this Acoustic Suspension principle from AR, Inc., and no:-" offers for the first time this remarkable speaker system in money-saving, easy-to-build kit form. The 10' Acoustic Suspension woofer delivers clean, clear extended range bass response and outstanding high frequency d!stribution is pro vided by the specially designed "cross-fired" two-speaker tweeter assembly. Another first in the Heathkit line is the availability of preassembled' . .and prefinished cabinets. Cabinets are available in prefinished birch (blond) or mahogany, or in unfinished birch suitable f()r the finish of your choic~. Kit assembly consists merely of mouD"ling the speakers, wiring the simple crossover network and filling toe cabinet with the fiberglass in clucled. Recommended amplifier W-7A. Shpg. Wt. 32 Ibs . 96 SPECIFICAnON5-Freguency response (at 10 watts Input)·: ±5 db, 42. 10 14,000 cps; 10 db down . $79 each • at 30 and 16,Q(X) cps; Harmonie distortion: below 2"/0 down to,50 cps\ below 3%. down to 40 cps at 10 watts • i" puUn corner room location. Impedance: 8 ohms. SUGgested damping factor: high (5:1 or greater). HEATHKIT AS-2U $69.95 •: Efficiency: about 2%. Distribution angI8: 9001" horizontal plane. Dimenslons:24"'W. x, '13Y," H. x 11%" D. (unfinished) • ·Power Input required for average listening level will not exceed 10 watts. • • THE WORLD 'S BIGGEST BARGAIN (N A HI-FI .AMPLIFIER • • 55 WATT HI-FI AMPLiFIER KIT (W-7A) • Utilizing advanced design in components and tubes to achieve unprece New • dented performance with fewer parts, H eathkit has produced the world's • first and only " dollar-a-watt" genuine high fidelity amplifier. Meeting • full 55 watt hi-fi rating and 55 watt professional standards, the new im • proved W -7 A provides a comfortable margin of distortion-free power for • any high fidelity application. • The sleek, modern styling of this unit allows unobtrusive installation • anywhere in the home. The clean, open layout of chassis and precut, • cabled wiring harness makes the W-7 A extremely easy to assemble. • Shpg. Wt. 28 lbs. • SPECIFICATIONS-Power output: Hi·fi rating, 55 watts; Professional rating, 55 watts. Power re. • sponse: ± 1 db from 20 cps to 20 kc at 55 watts output. Total harmonic distortion: less than 2% from 30 • cps to 15 kc at 55 watts output. Intermodulation distortion: less than 1% at 62 watts output using 60 cps • and 6 kc signal mixed 4:1. Hum and noise: 80 db below 55 watts, unweighted. Damping factor: Switch • on front panel for se lecting either maximum (20:1) or unity (1:1) . Output impedances: 4, 8 and 16 ohms • and 70 volt line. Power requirements: 117 volts, 50/50 cycles, 90·160 watts. Dimensions: 8X - D. x • 6y.- H. x 15' W, • • A NEW AMPLIFIER AND PREAMP UNIT PRICED WELL WITHIN • ANY BUDGET 14 WATT HI-FI AMPLIFIER KIT (EA-3) Delivers a full 14 watts of hi-fi rated power and easily meets professional standards as a 12-watt amplifier. Rich, full range sound reproduction and low noise and distortion are achieved through careful design using the latest audio developments. Miniature tubes are used throughout, including EL-84 output tubes in a push-pull output circuit with a special-design output transformer. The built-in preamplifier has three separate switch-selected inputs for mag netic phono, crystal phono or tape, and AM-FM tuner. RIAA equaliza tion is featured on the magnetic phono input. Shpg. Wt. 15 lbs, • NOTE THESE OUTSTANDING SPECIFICATIONS-Power output: 14 watts, Hi·!i; 12 watts. • Professional; 16 watts, Utility. Power response: ± 1 db from 20 cps to 20 kc at 14 watts output. Total • harmonic distortion: less than 2% , 30 cps to 15 kc at 14 watts output. Intermodulatlon distortion: less • than 1% at 16 watts output using 60 cps and 6 kc signal mixed 4:1. Hum and noise: mag phono input, • . 47 db bel ow 14 watts: tuner and crystal phono, 63db below 14 watts. Output impedances: 4, 8and t6ohms. r"..,..------.,""""""-----.-..,.,.--~-_,,=--...... "UNIVERSAL" 14 WATT HI-FI AMPLIFIER KIT (UA-2> M eeting 14-watt " hi-fi" and 12-watt " professional" standards, the UA-2 . HEA TH1
8 AUDIO • MARCH, 1960 New Tape Recorders
PROFESSIONAL QUALITY TAPE RECORDER KITS STEREO-MONO TAPE RECORDER KIT (TR-1A series) (TR-1 series) Our most versatile tape recorder kit, you can buy the new two These outstanding tape recorder kits offer a combination of track (TR-IAH) or fou~-track (TR-IAQ) versions which record features found only in higher priced professional equipment and playback both Stereo and Monophonic programming or selling for $350 to $400. The precision tape m echanism is sup the two-track Monophonic record-playback version (TR-1 A). plied completely assembled and tested, you build only the t.ape Precision bearings and close machining tolerances hold flutter ampli fiers. Two circuit boards are used for easy assembly and and wow to less than 0.35%. NARTB equalization, separate high stability. Separate record and playback heads and"ampli record and playback gain controls and a safety interlock. Pro fiers allow monitoring while recording. Features inClude pro vision for mike or line inputs with 6E5 " magic eye" tube as fessional-type db sound level meter, counter, pause control, sound level indicator. Two circuit boards for easy assembly. record interlock, 2 (switch-selected) speeds 3% and 7J1z IPS. Frequency response: ±2.5 db 30 to 12,000 cps at 7J1z IPS. MODEL TR-1A: Monophonic two-track record/ playback with fast NARTB equalization. Provision for mike or line inputs. Shpg. forward and rewind functions. Includes one TE-4 Tape Electronics kit. Shpg. Wt. 24 lbs. $9995 Wt. 30 lbs. $10.00 ON. , $9.00 MO. TR.1A Specifications-Frequency response: 7.SIPS ±3 db so to 12,000 cps; 3, 75 IPS ±3 db 50 to 7,000 cps. Signal-ta-noise ratio: better than 45 db below full output of 1.25 vo lts ! MODEL, TR-1E: 4-track stereo playback, mono channel. Harmoni c distortion: less than 2% at full output. Bias erase frequency: 60 kc phonic record & play. $17.00 ON ., $14.00 MO. (push-pull oscillator}. MODEL TR-1AH: Two-track monophonic and stereo record/playback with fast forward a nd rewind functions. Two TE-4 Tape Electronics MODEL TR-1D: 2-track stereo playback, mono phonic record & play. $17 .00 ON ., $14.00 MO. kits. Shpg. Wt. 36 lbs. $14995 $15.00 ON ., $13.00 MO. TR.1AH Specifications-Frequency response: 7.51PS ± 3 db 40 to 15.000 cps; 3.75 IPS ±3 db 40 to 10,000 cps . Signal-ta-nolse ratio: 45 db below full output of 1 volt /channel. MODEL TR-1C: monophonic record & playback. Harmonic distortion: less than 2% at full output. Bias erase frequency: 60 kc )push·pull $16.00 ON ., $14.00 MO. oscillator. MODEL TR-1AQ: Four-track monophonic a nd stereo record/playback MODEL C-TR-1D : Converts TR-ID to TR-IE. 2lbs. $14.95 with fast forward and rewind functions. Two TE-4 Tape Electronics MODEL C-TR-1C : Converts TR-IC to TR-ID. 2lbs. $19.95 kits. Shpg. Wt. 36 lbs. $14995 $15.00 ON ., $13.00 MO. MODEL C-TR-1CQ: Converts TR-IC to TR-IE. 2 lbs. $19.95 TR-1AO Specifications-Frequency response: 7.5 IPS ± 3 db 40 to 15,000 cps; 3.75 IPS ±3 db 40to 10,000 cps. Signal-to-noise ratio: 40 db be low full output of .75 volts /channel. Harmonic distortion: less than 2% at full output. Bias erase: 60 kc (pu sh·pull oscillator).
HEATH COMPANY/BENTON HARBOR 25, MICH. []~)Subsidiary of Daystrom, Inc.
o Plea se sen d the latest Free Heathkit catalog. Enclosed lind $ Please enclose postage for name parcel post-express orders are shipped delivery charges col l ect. A ll pri ces F.O.B. address Benton Harbor, Mich. A 20% deposit is required on all C.O.D. orders. Prices subject city & state to change without notice . . . Write today for, free catalog describ Ing over 100 easy-to-bulld kits In,hl.fi test-marine and amateuF radio fields, ,
______....'-- _____------.------.-L-
AUDIO • MARCH, 1960 9 soloist are cellos miked for optimum grutr ness and a percussion section comprising tam· tam, xylophone, vibrnhnrp, nnd the small hand cymbals of India. Lena Horne: Songs By Burke and Van ' Heusen 'RCA Victor LSP 1895 Lena Horne is still the queen of the care fully chiseJed casual phrase anel this collec tion of Johnny Burke-Jimmy Van Heusen tunes tnilors easily to her style. As a matter of COUl'sa, Lennie Hayton's ' orchestra tnkes cnre of instrumentnl duties in Victor's Studio 1\. Stereo placement Is straightforward-the now almost standard center location for the yocnlist. There is a mature disinclination to toss the accompaniment from one part of the orchestra to the other. A trace of sibilance sometimes encountere,d with condenser mikes accompan ies some of the lyrics. Pickup of voice is clean enough to accommodate mild CHESTER SANTON ';' rollo1l' of highs. This disc Is sure to receive repeated plays wherever top styling Is ad mired. Some may miss the rapport with an a udience that was an important part of the batch of "saltshaker" Western E lectric Lena Horne's Waldorf-Astoria session but the mikes we had. essen tial magic Is still here. The symbol • indicates the United Although the Air Force Band recreated on Stereo Tapes 4-track 7 Vz ips tape this record emphasized strings in its ballads, Sammy Davis: Porgy and Bess number. When Mr. Santon has lis the reeds and brasses are still in the style Decca .ST 7-8854 Dec. 78854 tened to - the tape only, the tape that had its origin in the late thirties. Johnny number is listed first. Otherwise, the Desmond, obviously moved by the reunion, One of the first Decca recordings released sings with great warmth in Night and Da'/I, by United Stereo Tapes cnrries a few sur corresponding tape number is fur Where or When, An the Things Yo" Are, prises for Davis funs as Sammy swaggers nished by United Stereo Tapes. Amor, and Symphony. The voice is centered through lead tunes from Gershwin'S Porgy in stereo that's spacious enough to recall the and Bess. The feminine songs a re handled lJand's t hentre appearances. with smooth authority by Carmen McRae. The advantages of tape show up best in the OP RECORDI NGS had a· relatively easy Japan: Its Sounds and People recording of the solo voices. In this respect, Capitol ST 10230 realism exceeds thn t of the disc previously is time during stereo's formative years. sued. A partial explanation lies in a reaSon PCompare the earliest pop and classical This is a very useful item to have on hand ably smooth frequency response that doesn't releases from RCA Victor, to take one when comparing stereo pickups, especially the imitate some of t he peaks found on other label almost at random. Issued at the same newer jobs that can do justice to some of the four-track tapes. Although three dlll'erent material on this record. There are plenty of conductors take turns on the podium, Sammy time, the Abbe Lane (LSP-1554) and Hi early stereo discs arqund thnt do not soun'] Da vis ties together one of the more likeable Fi Fiedler (LSC-2100) stereo discs pro significantly better with an up-to-date cart and believable Porgy and Bess albums, vide quite a contrast. P lay them with to ridge but this on-the-spot recording by Japa nese engineers should arouse interest among day's pickups and you'll find less distortion audio fnns. Some of the sounds associated George Wright: Have Organ Will Tra ve l ill the pop release. The wider dynamic with everyday l ife in Japan have been proc Hi Fi .R 721 range of classical music created another essed by Capitol with wnve-fronts steep The four identical woofers in my reviewing problem for the first stereo cutting heads. enough to present a cruel facade to most rig jumped forward to the end of their excur stereo pickups available today. In one of the sion when I fed them the pedal notes in this If you recall, it was a long time before episodes, n night watchman on the lookou t the level on the classical disc came up to recording of the Wurlitzer orgnn at the Fox for fires strolls past the microphones clap Theatre in San Frnncisco. George Wright Is the pr.esent-day figme. Even the succeeding ping together polished blocks of very hard, nn old hand at this sort of foot work. His models of stereo cutters wel'e not immedi seasoned wood. My next-to-last cartridge, val mono discs contained more than an inkling ued for its pleasing musical quality in earlier of extreme lows but it takes a tape to really ately used at full level because some of the stereo days, simply does not make the grade pickups, in the monitoring of test press let them loose. The travel theme gives Wright on these transients. Similarly, the tug boats a good excuse to indulge his sense of humor ings, gave a false picture of permissible and temple drums <10 not rench full definition in non·<1omestic settings of a.,.anacla, Jstan in the bottom lows until I switch to my latest recording level. At the present time, classi ~1I1, ApI'i! in Pari8, an<1 Sabre Dance. stereo pickup. cal and pop recor dings are pretty evenly Other insights into Japanese life include matched but, w hile this col umn is in wrestling matches, a tuna fish auction, gongs Sabicas: Furioso progress, I shall be listening to the former and fireworks. The songs of geisha girls anil Decca .ST 7-8900 Dec. 78900 for relaxation. the music of native string instruments rounil out the local color, The record, quite inci Cuadro Flamenco dentally, also reveals how much Western in Elektra • ETC-1504 Elek 259X STEREO PHON Ie fl uence is to be found in Japan by now. The traffic, fi re engines, and trains sound very like Flamenco recordings show every sign of our own. Perhaps the oddest touch in the carving their best niche in the tape catalogs. Johnny Desmond: Once Upon A Time Castanets, gui tars, gypsy Singers, and danc Columbia CS 8194 album is a brief portion of a serYice held in Tokyo's Greek Orthodox Cathedral. ers manage very well wi thin the presen t fre This release strikes me as the most suc quency range of four-track open-reel tape. cessful recreation to date of an outfit that Clebanofl': Songs From Great Shows I like the way a good stereo disc handles has become a legend-the Glenn Miller Air orchestrnl overtones above 10,000 cps but it Force Band. Johnny Desmond first hit the Mercury SR 60065 must be admitted that tape alone can now limelight as vocalist with MiJler's military Ench new Clebanoll' stereo release crum take the full wallop when the performer's nggregatlon. Now, fifteen years later, more bles away some of my former objection to n heels strike the floor iu Flamenco dancing. than half of the original members of thc stUdio full of mikes. Mercury's Chicago crew Dolores Vargas, known in her world as the orchestra assembled for this recording session has worked out a system of multiple-channel "Gypsy Enrthquake," scorches the boards of to accompany Desmond in the original ball nd recording that can lull the ear into the belief the floor in this performance. The tenm of arrangements he had used with the band in that it's getting normal stereo. The fi rst clue guitarists accompanying Sabicas, Los Com personal appearances and on V-Discs. I to the arbitrary nature of the proceedings is paneros del Flamenco, helps to fill out t he found It impossible to listen to this recorll the absence of room noise that usually woulrl stereo area. A solo guitarist. no matter how with any semblance of detachment. D uring surround a group of this size. Closer listening tnlented, still sounds rather lonely in stereo. my early days in broadcasting, I hnd an reveals that the playback area has a lateral The sound is the most vibrant I've heard so nounced, for nn en ti re summer, the first series series of dovetailing tonal images that reach fnr on four-track. of network remotes by the Miller band when from speaker to speaker. Each Image repre E lektra's F lnmenco team, two dancers, a Mutual carried them from Atlnntic City. The sents the signal of a separate group of instru singer nnd n guitarist, doesn't have the flu ir bnnd was so new at the time (I t had been ments. Clebanoll"s solo violin shares little of nnd virtuosity of the Sabicas group. On the organized in Boston on ly a few months be the acoustical environment belonging to the other hand,. several Spanish ensembles now fore) thnt Its theme song didn't have a title violas and cellos. Accustomed to stereo's direc before the public would sound tame under and Glenn spent every spare moment before tionality, the ear accepts most of this concept. similar comparison. If you're not too familiar broadcasts trying to get the best sound with H it songs from Broadway shows of the past with most of the F lamenco recordings on the two decades are grist for the Clebanoll' ap market, the Elektra entry will fill the bill. * 12 Forest Ave., Hastings-On-Hud,on, proach. His mikeslde manner is still the most The aficionado will prefer Sabicas. New York. soothing in the business. Neatly balancing the (Oontinu.cd on page 13)
10 AUDIO • MARCH , 1960 A TRUE STEREOPHONIC AMPLIFIER Equipped ~ith Independent AM·AM/FM Tuners SM-QI40 I The SM -Q140 is a stereophonic amplifier equipped with two SPECIFICATIONS OF THE SM.Q140 independent tuners, one an AM -Short wave tuner and the other I _ an AM-FM tuner. It provides not only stereophonic playback Tubes Used: 14 tub:es plus 4 germanium diodes of disc recordings but also reception of AM-AM stereophonic Tuners: Channell: AM medium wave and AM shortwave Channel 2; AM medium wave and FM broadcasts, AM -FM stere.ophonic broadcasts, or simulta"tieous Maximum Outputs: Monophonic Operation-I5 watts reception of two different broadcasts. In addition, it is Stereophonic Operation-6 watts per channel capable of simultaneous playback of two different disc re - ·· Rated Outputs: Monophonic Operation-I2 watts cordings using two separate record players, simultaneous Stereophonic Operation-5 watts per channel playback of disc recordings and reception of radio broadcasts, Channel Separation: -52 db or even simultaneous recording of these various program Dimensions: Width 19" x Depth 11 " x Height 6' sources in conjunction with a tape recorder. Weight: 27 Ibs.
TRANSISTOR HEAD-AMPLIFIER (Preamplifier) For Use With High Quality Low Output Magnetic Cartridges The STP-l is 4-transistor stereophonic head-amplifier (preamplifier) designed to enable the use of high quality low output magnetic type . pickup cartridges in conjunction with amplifiers designed mainly for use high output with crystal or ceramic type pickup .cartridges. When using variable reluctance moving-magnet, or moving coil type low output pickup cartridges, all you do is connect the STp·l between the pickup and the amplifier, using the shielded coaxial cable provided. AM-FM TUNER Through the use of transistors, the signal-to'noise ratio is ex SIP - I tremely high and there is AFT-II absolutely no hum or noise. The AFT-ll is a highly versatile tuner unit incorporating Using high quality cartridges in two indepentJent AM and FM tuners. It may be usep conjunction with the STP-l and fOf reception of stereophonic broadcasts in conjunction a PIONEER SM-Q140 will pro- vide the ultimate in high quality .- .with all types of amplifiers. playback of stereophonic disc : recordings. FUKUIN ELE ' IC,"TOKYO, JAPAN Bunkyo.ku, Tokyo
AUDIO • MARCH, 1960 11 CONFIDENTIAL AUDIOMAN NO.6 INFORMATION Robert F. McDonald, lithogra'pher, long-time hobbyist, organ builder, kit constructor, Siamese cat breeder, rifleman, sports car Not so long ago the mahatmas ot hi fI were solemnly preaching anent loud enthusiast, ·and occasional tennis player, joins list of Audiomen. speaker enclosures that " t he bigger the box, the bet ter the sound." Since the ANUAL DEXTERITY appears to be the adven t of stereo, this catch-phrase Is no main element in common among the longer heard. The reason, obviously, Is M various hobbies of this mont h's purely commercial. The monaural market was able to swallow one big box, but the Audiomau- with t he possible exception of stereo ma rket couldn't swallow two. Siamese cat breeding, which he does only in a small way anyhow. But it is inter est Since necessity Is the mother of In vention, this situation created a galaxy ing t o note that those who have made a ot new geninses. Though they had never hobby of audio seem also to share t heir thonght of It before stereo, or even said time with other hobbies that involve work It conldn't be done, there suddenly ap ing with their hands- we rarely encounter peared a rash ot small boxes, even "shelf-size," all with the most astonish an audiofan who is an avid student of Ing attributes. They were "even better" history, for example. than their big brothers. Actually, they Mr. McDonald, who lives in Oakland, were nothing more than smaller versions ot the same old bass-reflexes and folded Ca lif01'llia, fi rst became interested around horns with their Inevitable boom and 1921, when his late father was building distortion. radio receivers, using them for a while, and Some time before this stereo-forced t hen selling them to f riends or neighbors miniaturization. an entirely new, defini (sounds familiar, doesn't iti). He r e tive and compact loudspeaker enclosure members loose couplers, variometers, fila was Invented . .. an Invention of such ment-current volume controls, storage· outstanding 'novelty and merit that fifteen claims . .. all that were asked battery power supplies (with occasional ... were allowed by the P a tent Office. holes in the carpet f rom spilled sulphuric Equally .-a luable foreign patents were acid), and even the olel Kellogg set which also granted. The principle was In used tubes with heater connections on a genious, logical and scientific, and should appeal at once to anyone who has per nnique dual t op cap- and the Kellogg set ception enough to g rasp the Idea. they had has been reconverted into a bar. The best loudspeaker enclosure Is. His first P .A. "system" was put together B ut since then he has moved upward con obviously, the totally enclosed cabinet in school to simulate .a broadcast-station t inually and his equipment r oster is now as because It Is entirely neutral and neither studio so the kids could put on their own fon ows: Heathkit SP-2 stereo preamp and adds to. nor takes from. speaker perform programs-a telephone transmitter, a bat ance. Unfortunately, It must be large X O-l electronic cr ossover, National Cri (20 cubic feet) or the enclosed air act. te1'Y-operated Westinghouse amplifier using terion tuner and Horizon 20 amplifier, as a cushion upon cone movement. WD-U's, and a mOl'lling-glory horn. Bogen DB-20, two Pilot AA410's, a Rek-O thereby Impairing reproduction. The H is first entry into the business pro K ut turntable, two Pickering arms and Bradford Baffie, by Its paten ted pressure fessionally was as a P .A. rental operat or relief valve, ellmlna tes this air pre. three picknps, a F airchild 225 pickup, and lure, and can, therefore. be made com· with a high·school friend, and he remem a speaker array consisting of an E lectro pact . .. only a few Inches larger than bers as a big event the acquisit ion of a Voice 15WK, Wharfedale 12CS/ AL and a the speaker Itself . . . without sacrific Brnsh Sound-Cell microphone, for which 3-in. tweeter, a 12-in. T annoy, and a J BL Ing any of the performance values In they had to build a preamp. When they herent In the large Infinite baffie. Fur D-130 in a Harkness enclosure. H is tape thermore, there is no cabinet resonance, went out on a job, it looked as though recorder is a Magnecord M-30, and he is boom or distortion. For these reasons. t hey had half of NBC with t hem, consider one of the first builders of a Schober organ the Bradford Baffie was and Is the ing the amplifiers, preamps, preamp power kit. only compact cabinet fully equal to, or supplies, speakers and field exciters, and better than, the large enclosures, either The illnstration at the lower left shows before or after stereo. remote boxes. After gettin g married, Mr. the monnting of preamp, t urnta ble, tuner McDonald either found no time or no Totally enclosed "acoustic suspension" and tape recorder in a River-Edge chair .ystems have become popular. The Brad mouey for andio eqnipment, so his own rig side cabinet , and one of his current proj tord Baffie was the original "acoustic had t o wait until he had some spare time ects is converting t he Magnecol'd to stereo. suspension," only better, for the degree in J apan while he was in the service. of " suspension" is automa tically self The E-V speaker is ill a home-built Georg adjusting. ian enclosure, which is topped with another enclosure that houses t he two 12·in. cones The Bradford Baffie is made In two sizes ... one for 89, lOs, and one for 12s and the 3-in. tweeter. For test equipment, and 15s, in all popular hardwoods, Mr. McDonald relies on Heathkits again priced from $34.50 to $69.50. Made and f or t nbe checker and V TVM. IInlshed better than most expensive, custom furniture. . Like most avid auc1iofans, Mr. McDonald has some ideas about equipment he would Sold separa tely, for only $85.00, Is the Bakers Ultra 12" speaker. For those like to see on the market. One unit in par who appreciate natural facsimile Instead tie-ular would combine t he f unctions of the of calculal!ed artificiality, this is the usnal preamplifier-control unit with its finest speaker ever made. Its superiority normal complement of inputs but would is accomplished by ingenious cone de sign, plastic foam surround, 18,000 gauss include, in addition, a recording amplifier magnet, and other exclusive features, with bias and erase provisions for each without which ultimate reproduction Is channel as well as t ape-head amplifier with impossible. proper equalization t o permit monitoring If you love music, unalloyed; if boom off the tape. In brief, what he wants, he and distortion shock your nervous sys says, is "complete electronics for every tern; and if you ha v.e ever stopped to wonder how the "bigger the box, the need, leaving the tape deck to mechanical better the sound" advocates can now considerations only as is t he case with disc promote "shelf-size," basN-reflexes and tnrntables." folded-horns that are "even better than A highly commendable suggestion, we ever," write for literature. Bradford Audio Corporation, 27 Ea st 38th St., say, and one which would be simple enough New York 16, N. Y. if all t ape decks had t he same require Advertisement ments. JE l2 AUDIO • MARCH, 1960 Verdict: Colla stereo record. players are Innocent of rumble, wow, flutter
or any nOIses that interfere with enjoyment of music
The Constellation, Model TC·99-$59.50 The Continental II, Model TSC·S40-$49.50 The Coronation II, Model TSC·740-$42.50 "The Conquest II, Model TSC·640-$38.50
Transcription Turntable, ModeI4TR·200-$49.50 Manual Player, Model TP·59-$29.95
Every Collaro stereo record player is built with typical British attention to every detail. They are precision engineered and rigidly tested to give truly profes sional performance and the ultimate in operating convenience. Here are some of the more important features that make Collaro the logical choice for stereo or monophonic records. • Performance specifications exceed NARTB standards for wow, flutter and rumble - with actual performance test reports accom· panying each model .TC-99 . • Extra-heavy, die-cast, non-magnetic turntables (we ighing up to 81f2 Ibs.l. Extra-heavy weight is carefully distributed for flywtl.eel effect and smooth , con stant rotation .• Shielded four-pole motors are preci sion balanced, screened with triple interleaved shields to provide extra 25 db reduction in magnetic hum pick-up .• Detachable five-term inal plug-in head shells (on TC-99, TSC-840, TSC -740, TP-591 provide two completely independent circuits, guaran teeing ultimate in no is e reduction circuitry . • Tran scription-type stereo tonearms are spring-damped and dynamically counterbalanced to permit the last record on a stack to be p.1a yed with virtually the same low stylus pressure as the first. • All units are handsomely styled, available with optional walnut, blond and • mahogany finished ba ses or unfinished utility base. There 's a 4-speed Collaro stereo record player for every need and budget! Prices slightly higher ill the u West. For free catalog on the Collaro line, write to : Rockbar Corporation, Dept. A-3, Mamaroneck, N. Y. (·Not shown. Similar in appearance to The Coronation.) c cost, counting labor, would have been arQund $12 to $14. Ray threw in a few odds and ends of improvement while we were at it, and polished up the wood work, cleaned and lubricated the changer-which still works like a charm. (I think it was a special V-M model, the type that doesn't shut off after the last record.) And, by golly, I now have what amounts to a brand new Columbia 360 table phono graph. It sounds terrific, much better than I would have imagined it could. My. point has been well proved, as far as this par ere. ticular six·year-old is concerned. Its in sides are in general perfectly good; there is no audible deterioration. The trouble Edward latnall.Canby was specific, in one particular part; it Then one boy took it to college with was not general debilitation, as most peo Don't Throw it Out him for the winter-by this time it was ple expect and as dealers so often imply. 1. Columbia 360 thought of as mainly a piece of junk, and Not out-of-date sound, either. Six years of to be sure, it looked it. Sounded it, too. ads have blown home hi-fi claims sky-high, I have a persistent way of keeping track He needed something-anything-and this but when you come down to earth, this of certain of my more elderly pieces of would do. I guess, come to think of it, hc Columbia 360 sounds just about as good as equipment, long after they are written up had the all·groove cartridge put in, for any comparable machine today and a lot in AUDIO and written off as no longer of about $10. (Bet it cost the service man better than some. current interest. The longer they stay all of 50c.) He fussed aronnd with it a Nope, it's not stereo. And as a matter around usefully, the better I like them. bit, but the machine just sounded worse of fact I was stupidly absent-minded in Mostly, these odds and ends of past epochs and worse and he almost threw it out not installhig a turnover stereo cartridge are farmed out to friends, in part just be (hooked up mono) so that the kids could cause I am interested to find out what only it wasn't his. happens to them under such dreadful So back it came and last summer I went play any old record on it, from 78's to to a folk dance party and met up with the stereo 7-inchers. Maybe I'll do that later. duress and-when it does, how they go But for a mono machine it's a bargin, at about describing the trouble to me and/or old beast once more, for what most cer what they do themselves to get it fixed. tainly appeared to be the very last time. $121 (Do I have my finger on the public In fact, the dance had to be cut short My conclusion: Servicing of component pulse in this respect I Other day, for in halfway through. The longer the old 360 hi-fi is a problem almost anywhere and we stance, a girl who sings in my chorus la played, the more fuzzy and fainthearted could do better. But repairs on "ordinary" mented that her phonograph was on the did the sound become, until finally it was home phonographs are absolutely outrage blink; she said it sort of groaned and the so dreadfully distorted we couldn't even ous. It seems as though nine times out of music played too slow. Changer motor catch the dance rhythms from it. Old piece ten, the way I hear it, service men care gummed up, I thought, and so I asked of junk, said the kid,s. We ought to get a fully and expensively replace parts that don't need replacing and fail to fix what her-remember, she's musical~I asked her new one ... and it was at that point that did the pitch sag when the machine played I boiled over (internally). Just let me is really wrong. Often they do more harm slow, did it get lower' "Oh no," she said look at it first, I said. than good, as in the all-groove cartridge brightly. "It stays right on pitch. No I took it home and turned it over to my deal, above. I won't go very far on a limb change at all I But the trouble is, the competent assistant, Ray Prohaska, who I).ere; my experience is not all-inclusive music plays too slow. What can I do'" knows a bit about electronics and hi-fi, and I haven't the facts and figures. No She's got me stumped, there. What would which is more than some servicemen know. doubt many repair men do fix the old ma you suggest!) I was just darned well going to find out chines the way they ought to be fixed. But Anyhow, back some six years ago, I what was really wrong with that machine to date I haven't heard of any such happy think it was, I wrote at length here about before ;it was junked for good. Isn't this occurrence, and my mistrust of such opera the first of the home-type "hi-fi" phono what hallpens to virtually every old phono tions is therefore prodigeous. graphs, the Columbia 360 in its original graph, after a year, or three or five ·' Are Maybe the home machines are junky. format. The machine was then really .quite they really just "worn out'" Are the parts Probably they are far less sturdy and re enterprising and original in desigp, of its really gone, the resistors and capacitors liable than component parts. But, I hereby now-familiar sort, and was the prototype shot or changed in value beyond practical suggest, the junky innards and sleazy con of millions since, both good and terrible. repair' struction are less often the cause of final It had two small speakers, one on each side Could be. But, this time, I was going to collapse than simply a series of ever-more of the cabinet, and the top closed to make find out. futile, ever-more-expensive wrong repairs, . a resonant chamber that peaked up a So we set 'er up in Ray's basement lab culminating in the inevitable "why don't considerable blast of fairly effective bass :-and, allowing for the dismal cartridge, you get rid of that piece of junk." -for a table box. The cartridge was a It sonnded fine, at first. That is, it played, good Sonotone turnover ceramic, the single and seemed. not to have ·anything seriously 2 . . Empire 98 tone control wisely did no more than pro wrong with it but just old age. Yet Ire· vide a limited roll-off, enough to com membered that dance. I figured: it had I am quite happy with my newest dis pensate for differences in room acoustics. been at least a half hour before the thing covery in the way of phono arms, the And, finally, an optional extension speaker became really fuzzy. Would any service Audio-Empire 98- "Stereo/Balance." No for highs (with clock) provided a tricky man listen for that long! discovery for the trade, of course, since pseudo-stereo spread of sound, long before Ray already thought he knew the an the arm is well known already; but in stereo itself had made this idea attractive swer, and he turned out to be right. Sure terms of first-hand satisfaction it has been to an inquiring public. enough, after a whole LP side of a bat a good discovery for me, so far. I first saw It was a good machine and, relatively, tered "Sacre de Printemps" (Ray's only this arm in action at last year's High a well made one. After a couple of years record), the famous Russian fertility rite Fidelity Show in New York. I've been I turned it over to the kids in our summer began to go askew. The thumps and bumps using it for some time now, with a Shure community in Connecticut, for muBie, became fuzzy, the volume trailed off dis M3D cartridge in its detachable shell. dancing, and whatever else kids usually tortion rose to hundreds of per cents. 'That This is a current example of the type of do with a phonograph. was it. arm that, to many people's utter amaze They did it. The original kids have So-Ray opened the machine up, re ment, will "play uphill," and in the stereo grown up and departed but the current placed a leaky capacitor that was throwing age this is a valuable feature. The arm is crop tells me that the thing broke down a positive current at the tube grids-after so balanced with its cartridge installed and they took it to the nearest big-small warming up-also replaced a small resis that you may tip the turntable sidewise town .radio repair, $18 including a new tor and both 35L6 tubes, for safety;· 'and until loose objects slide downhill, yet the sapphire nee.dle. It broke downagain-(they put it all together again. Cost of parts music plays on, never missing a groove-in say) and went back a second time. It must $2.57. The thing worked like new. the case of the Empire 98 even at 2 or 3 have been on this trip that it acquired a Except, of course, for the cartridge. We grams stylus force. Astonishing to watch, new cartridge. I was horrified-the excel put in another Sonotone, twin of the origi but also practical in all cases where turn lent Sonotone was replaced by a cheap all nal (what'll you bet it never was bad at tables are apt to be out of level, which groove model of highly doubtful tone and all) and got us a diamond needle. But if is virtually always in most homes, unless worse effect upon our records. it hadn't been for that, the proper repair (Continued on page 44)
14 AUDIO • MARCH, 1960 3-Way Speaker System HFS3 2-Way Bookshelf Speaker Systems 100W Stereo Power Amplifier HF89 HFS5 and HFS1 70W Stereo Power Amplifier HF87 28W Stereo Power Amplifier HF86 Stereo Integrated Amplifier AF4tt
• Exclusive advanced systematized engineering FM Tuner HFT90: Prewired, prealigned, tempera HWD: 24", 12V2", 10V2". Unfinished b; ;': h $47.50. • Lastest .and finest quality parts ture·compensated "front end" is drift-free. Pre Walnut, mahogany or teak $59.50. • Exclusive "Beginner-Tested" easy step-by- wired exclusive precision eye-tronic® traveling HFSl Bookshelf Speaker System complete with step instructions tuning indicator. Sen sitivity: 1.5 uv for 20 db factory-built cabinet. Jensen 8" woofer, match • Exclusive TRIPLE quality control qUieting; 2.5 uv for 30 db qui eting, full limiting ing Jensen compression·driver exponential horn • Exclusive LIFETIME guarantee at nominal cost from 25 uv. IF bandwidth 260 kc at 6 db points. tweeter. Smooth clean bass; crisp extended IN STOCK - Compare, then take home any EICO Both cathode follower & FM -multiplex stereo highs. 70-12,000 cps range, 8 ohms. HWO: 23" equipment - right " off the shelf" - from 1500 outputs, prevent ob sol es cence. Very low distor x 11" x 9". Price $39.95. tion. "One of the best buys in high fidelity kits." neighborhood EICO dealers throughout the U. S. HFS2 Omni-Directional Speaker System (not iIIus.) and Canada . - AUDIOCRAFT. Kit $39.95 *. Wired $65.95*. 1 1 Cover $3.95. * Less cover, F.E.T. incl. HWD : 36", 15 /4", 11 12". "Fine for stereo" - HF81 Stereo Amplifier-Preamplifier selects, MODERN HI-FI. Completely factory·built. Mahog amplifies, controls any stereo source & feeds it AM Tuner HFT94: Matches HFT 90. Selects "hi-fi" any or walnut $139.95. Blond $144.95. thru self·contained dual 14W amplifiers to a pair wide (20·9000 cps @ -3 db) or weak-station New Stereo Automatic Changer/Player: The first narrow (20-5000 cps @ - 3 db) bandpass. Tuned of speakers. Provides 28W monophonically. & RF stage for high selectivity & sensitivity. Pre only LUXURY unit at a popular price! New Ganged level controls, separate balance control , unique engineering advances no other unit can independent bass and treble controls for each cision eye-tronic® tuning. "One of the best available." -H I-FI SYSTEMS. Kit $39.95. Wired after regardless of price: overall integrated channel. Identical Williamson-type, Dush-pull design, published frequency response, stylus EL84 power amplifiers. "Excellent" - SATURDAY $65.95. Incl. cover & F.E.T. pressure preCision-adjusted by factory, advanced REVIEW. "Outstanding ••• extremely versatile." New FM/AM Tuner HFT92 combines renowned design cartridge. Compact: 103/4" x 13". Model - ELECTRONICS WORLD. Kit $69.95. Wired EICO HFT90 FM Tuner with exc,ellent AM tuning 1007D: 0.7 mil diamond, 3 mil sapphire ' dual $109.95. Incl. cover. facilities. Kit $59.95. Wired $94.95. Incl. cover stylus - $59.75. Model 1007S: 0.7 mil & 3 mil HF85 Stereo Preamplifier: Complete master & F.E.T. sapphire - $49.75. Includes F.E.T. stereo preamplifier-control unit, self-powered. New AF-4 Economy Stereo Integrated Amplifier Distortion borders on unmeasurable. Level , bass, provides clean 4W per channel or 8W total out & treble controls independent for each channel put. Kit $38.95. Wired $64.95. Incl. cover & F.E.T tShown In aptional Furniture Wood Cabinet or ganged for both channels. Inputs for phono, HF12 Mono Integrated Amplifier (not iIIus.): Com WE71: Unfinished Birch, $9.95; Walnut or tape head, mike, AM, FM, & FM·multiplex. One plete "front end" facilities & true hi-fi perform Mahogany, $13.95. each auxiliary A & B input in each channel . ance. 12W continuous, 25W peak. Kit $34.95. ttShown in optional Furniture Wood Cabinet "Extreme flexibility ••• a bargain." - HI-FI Wired $57.95. Incl. cover. WE70: Unfinished Birch, $8.95; Walnut or REVIEW. Kit $39.95. Wired $64.95. Incl. cover. New HFS3 3·Way Speaker System Semi· Kit com Mahogany, $12.50_ New HF89 100-Watt Stereo Power Amplifier: plete with factory·built 3/4" veneered plywood (4 Dual 50W highest quality power amplifiers. 200W sides) cabinet. Bellows·s uspensi on , full-inch ex A·3 peak power output. Uses superlative ultra-linear cursion 12" woofer (22 cps res.) 8" mid-range EICO, 33·00 N. Blvd., L.I.C. 1, N. Y. connected output transformers for undistorted speaker with high internal damping cone for Show me how to SAVE 50% on easy-to-build response across the entire audio range at full smooth response, 3'/2" cone tweeter. 2V4 cu. ft. power, assuring utmost clarity on full orchestra top-quality HI-Fi. Send FREE catalog, Stereo Hi-FI ducted-port enclosure. System Q of '/2 for Guide plus name of neighborhood EICO dealer. & organ . 60 db channel separation. 1M distortion smoothest frequency & best transient respon se. 0.5% at lOOW; harmonic distortion less than 1 % 32-14,000 cps clean, useful response. 16 ohms Name ...... from 20·20,000 CDS within 1 db of lOOW. Kit impedance. HWD: 261f2", 137/8", 143ffl". Un $99.50. Wired ~'3 9 . 50 . finished birch $72.50. Walnut, mahogany or teak Address ...... HF87 70·Watt Stereo Power Amplifier. Dual 35W . $87.50. City ...... Zone ...... State ...... power amplifiers identical circuit-wise to the New HFS5 2 ~ Way Speaker System Semi-Kit com superb HF89, differing only in rating of the out plete with fa ctory·built 3/4 " vene ered plywood put tran sformers. 1M distortion 1 % at 70W; (4 sides) cabinet. Bellows·suspension , 5/8" excur harmonic di stortion less than 1 % from 20·20,000 sion, 8" woofer (45 cps. res. ), & 31f2" cone Li sten to th e EICO Hour, WABC-FM, N. Y. , 95.5 MC, cps within 1 db of 70W. Kit $74.95. Wired $114.95. tweeter. IV4 " cu. f t. ducted-port enclosure. Sys Mon. to Fri. 7:15·8 P. M. , Sat. 11-12 P. M. Ask HFa6 2a-Watt Stereo Power Amp. Flawless repro tem Q of V2 for smoothes t frea. & best transient dealer about EICO's Stereo Records Bonus. duction at modest price. Kit $43.95. Wired $74.95. resp. 45·14,000 cps clean , useful resp. 16 ohms. © 1960 by EICO, 33·00 N. Blvd., L. I. C. 1, N. Y_
AUDIO • MARCH, 1960 15 \ EDITOR'S REVI EW
LIGHT LISTENING of his exhibit area and for some of the other features of the San Francisco show, and although the situation OR YEARS, readers have been suggesting that we was still far from ideal as regards acoustics, it must recognize the import.ance o~ "in~between" mus~c be admitted that the Cow Palace is better suited for Fwhich does not fall rIghtly mto either M. C~nby s a hi-fi show than the Pan-Pacific Auditorium. To classical RECORD REVUE or Mr. Robertson's JAZZ AND begin with, the ceiling-typical of a factory sawtooth ALL THAT but we have never found the right man to roof-was lower and did not serve as a concentrator do the job to our satisfaction. But the resurgence of for all the sound originating under it. The exhibits the stereo tape market, particularly in the four-track were in one of the side halls, and not in the cavernous 7Y2-ips reel-to-reel field, has made this type of music main arena area of the Palace, which would undoubt more important to the listener than ever before. It is edly have been as objectionable as the Pan-Pacific. not the function of our ·· record review columns to Booths were arranged in rows, separated by wide attempt coverage of every disc issued, particularly the aisles, and each row of booths faced on its own aisle 45-rpm singles, but there are many of us who enjoy so there were no facing entrances from booths across music in the lighter vein at times when neither the aisle from each other. The exceptions were on one Frescobaldi nor Prokofiev seem to suit our mood, and end where the wall booths were facing the entrances when Brubeck and Hampton seem a bit too noisy for to the demonstrating booths, but those along the wall relaxation. At such times, we just might enjoy show were not supposed to make any sound anyhow tunes or possibly a pot pourri of listemible music for although a few did, nevertheless. Then, too, all of the incidental listening, as contrasted to "cidental" listen sound booths were roofed with fiberglass which de ing-as described in these pages many years ago by creased the high-frequency sound radiation appreci an old friend, J. N. A. Hawkins. ably. True, there was a fairly high level of muffled We feel that we were fortunate in securing the sound in the aisles, but in the booths themselves it was services of Chester Santon to cover this particular possible to obtain a fairly good demonstration without area of music, which appears under LIGHT LISTENING too much interference. It was not perfect, by far, but beginning on page 10 of this issue. Predominantly, we fail to see how any arena show can do much better. his reviews will be of four-track tapes, which are in Another innovation introduced by Mr. Logan was practically every case paralleled by LP's. the provision of a nursery area for children-this Mr. Santon is well known . to New York radio feature alone must have saved exhibitors literally tons listeners-and over the QXR network in upper New of literature-where the kiddies could be parked and York State and in Connecticut and Massachusetts entertained in a manner far more attractive to them for his Sunday evening" Adventures in Sound" pro than traipsing through the exhibits would have been. gram which was on the air for several years, only TV and radio personalities accustomed to entertaining recently having been displaced by another program children were on hand, and a registered nurse was in with considerably less interest to most of us. He has i, attendance at all times so parents could leave their a particularly large following in the Schenectady offspring without a single worry. To these large points Troy-Albany area, where he has been a guest speaker in favor of the S.F. show we must add that two large at meetings of the Tri-City Hi-Fi Association on studios were available for recording aggregations who several occasions. We feel that we are fortunate in entertained the visitors, refreshments were conven having Mr. Santon join us and trust that r eaders will iently available and parking was free with no more welcome this additional musical coverage. than about 500 feet to walk from your car to the Palace. We feel that this was an excellent show, and that SAN FRANCISCO HI-FI SHOW Mr. Logan deserves considerable credit for the way he While our comments last month on the Los Angeles carried it off. We won't say it was perfect, but we High Fidelity Show were not altogether complimen have yet to see a perfect set-up for~ a hundred exhibi tary, we were unable-because of deadlines-to get in tors to create sound levels of 90 to 100 db in their a few words about San Francisco's show. Perhaps, own booths and still have the booths close enough for however, the contrast will not be as drastic whIm people to get from one to another without a block's separated by a month as it would have been if both walle If anyone has ideas about how this can be done, had been covered on the same page. we think the industry would be glad to hear about Jim Logan deserves a lot of credit for the layout them.
16 AUDIO • MARCH, 1960 flHl~
Roy.,r System Wa ll Cabinets designed by Poul C. davlus..
Here is more for the best of everything in quality record reproduction-the more that makes the difference! more output!. .. more channel separation! ... more response ... more record life! In short-more to enjoy because there's more quality for more listening pleasure. Without question, Pickering's Collectors' Series 380 is the finest-with more features and more flexibility than any other stereo pickup in the world. For example, the 380 is fully encapsulated in radiation· proof precious mu·metal for absolutely hum·free performance in any record player regardless of type-make-model. The only true way to judge a high fidelity component is to compare it with another . .. measure its performance with the most vital instrument of all •.• the ear. For-those who can hear the difference choose PICKERING*. COLLECTORS' SERIES 380. Totally new and unique to high PRO·STANDARD SERIES 371. Now, the new and fidelity is the " Collectors' Ensemble" . .. a complete quality "pick· revolutionary PACt technique developed by ~ up· package" for reproduction of all records - stereo, micro· PICKERING has effected· economies in groove. 78·s. manufact ure which permit a reduction in the price of the Pro·Standard Series . .. an industry OUTPUT: 15 mv per channel. CHANNELSEPARATlON: 30·35 db. standard and the universal choice of professionals. FREQUENCY RESPONSE: + 2 db 20·20,000 cycles. SIGNAL TO Features four coil push.pulr hum rejection circuit. NOISE RATIO: -65 db below reference. TRACKING FORCE: "An OUTPUT: 10 mv per channel. CHANNEL SEPARATION: 20.25 db. type stylus-2·5 grams; "c" type stylus-3·7 grams. FREQUENCY RESPONSE: 20·15,000 cycles. TRACKING FORCE: Model 380E Collectors' Ensemble includes the Stanton Stereo "A" type stylus-2·5 grams; "e" type stylus-4·7 grams. FLUXVALVE with 3 "V·GUARD" styli for stereo. microgroove and 78 rpm records ...... $60.00 Model 371A Mk " Stanton Stereo FLUXVALVE Pickup now $26.40 Model 380A includes Stanton Stereo FLUXVALVE with D3807A Model.371C Mk" Stanton Stereo FLUXVALVE Pickup now $24.00 "V·GUARD" stylus for transcription arms ...... $34.50 Model 196 Mk " UNIPOISE Arm with integrated Stanto!) Stereo Model 380C includes Stanton Stereo FLUXVALVE with D3807C FLUXVALVE Pickup now ...... : • •• ••.•• •.. $49.50 " V·GUARD" stylus for auto·changer arms.• .. . .••. ••. • $29.85 Only the Stanton Stereo FLUXVALVE FOR THOSE WHO CAN HEAR THE DIFFERENCE features the safe, comfortable, easily P replaceable stylus assembly. 0PICKERING-for more than a decade-the world's most experi· enced manufacturer of high fidelity pickups ... supplier to the recording industry. . tPI CKE RING AUTOMATED CRAFTSMAN SHIP UNEWYORK FLUX VALVE. ··V.GUARD" " T.GUARD'· U NI P O I S E PAC ( T M ) PICKERI~O" J~~~!l~ AUDIO • MARCH, 1960 17 \ HE X-RAYS WOOD ·... to help make telephone poles last longer
Chemist Jack Wright developed the use of this X-ray fluorescence machine for testing the concentration of preservatives in wood. Here he bombards a boring from a test telephone pole with X-rays.
This Bell Labs chemist is using a fast, new technique for measuring the concentration of fungus-killing' preserva tive in telephone poles. A boring from a test pole is bombarded with X-rays. The preservative-pentachlorophenol-converts some of the incoming X-rays to new ones of differtnt and charac teristic wave length. These new rays are isolated and sent into a radiation counter which registers their intensity. The intensity in turn reveals the concentration of preservative. Bell Laboratories chemists must test thousands of wood specimens annually in their research to make telephone poles last longer. Seeking a faster test, they explored the possibility of X-ray fluorescence-a technique developed originally for metallurgy. For the first time, this technique was applied to wood. Result: A wood specimen check in just two minutes-at least 15 times faster than before possi ble with the conventional microchemical analysis. Bell Labs scientists must remain alert to all ways of improving telephone service. Th"ey must create radically new technology or improve what already exists. Here, they devised a way to speed research in one of telephony's oldest and most important arts-that of wood preservation.
Nature still grows the best telephone poles. There' are over 21 million wooden poles in the Bell System. They requ ire no painting, scraping or cleaning; can be nailed, drilled, cut, sawed and climbed like no other material. Scientific wood preservation cuts telephone costs, conserves valuable timber acres.
BELL TELEPHONE LABORATORIES World Center of Communications Research and Development An Adiustable Power Supply
JOHN P. WENTWORTH ';'
For the many applications requiring a readily controllable d.c. voltage, this simple power supply will provide the answer. Not automatically regulated, the unit will provide voltages adjustable within close limits.
ANY omOUITS have been proposed for a power supply with variable Moutput voltage, ranging from a simple rectifier-potentiometer combina tion to the ingenious controlled rectifier proposed by Peschel.!· 2. 3 However, t he author has not seen to date a really simple circuit that will provide con II II tinuous variation of voltag'e from maxi mum all the way to zero, except for the primitive method employing a potenti ometer in the output. The circuit shown (B) in Fig. 1 fills this gap. To understand the operation of this Fig. 2. Equivalent circuits of the power supply at (A) zero output setting, and (B) circuit, consider the simplified diagram maximum output setting. at (A) in Fig. 2. Alternating voltages tors to maintain the grid voltage below components will depend on the type of 180 deg. out of phase are applied to the cut-off during most of the cycle. The tube used for the rectifier. For the sake grid and plate of each triode, so that, small pulse of charging current is sup of simplicity, it was decided to use tri whenever the p late of one section is posi plied through a very high impedance, odes, or triode-connected tetrodes or tive, its grid is driven negative. If the and does not produce a measure able out pentodes, rather than to worry about grid drive is sufficient, the tube remains put voltage. screen and suppressor connections. Of cut off. On the other hand, when the grid Now suppose that a short circuit is the many tubes that would be suitable is allowed to swing in the positive direc connected between the two grids, as for this application, including the tion, the plate is negative, and there is shown at (B) in Fig. 2. If the resistances 6AS7G and triode-connected 6L6's and again no p late conduction. Grid con in this circuit are properly proportioned, 807's, the 6AS7G was chosen by the duction is held to an insignificant value, there will be no alternating voltage at author, in spite of its high price, for as the small pulse of grid current on the grids, and the triodes will operate the following reasons ; each cycle charges the coupling capaci- continuously at zero bias, producing a L The two triode sections required high direct voltage output. If, on the for a full-wave rectifier are included } 2531 Key Bouleva?'d, Arlington 1, Va. other hand, a finite resistance is con in a single envelope. nected between the two grids, the output 1 S. S. Peschel, "Power supply output 2. The zero-bias resistance is lower voltage control." Radio ~ TV News, Oc· voltage will be somewhere between the than that of the other tubes, leading tober, 1948. two extremes. Use of a rheostat, as in one to expect a higher maximum out 2 S. S. Peschel, "Novel controlled recti Fig. 1, permits continuous variation in fier." Radio ~ TV News, November, 1948. p ut voltage. output. 3 Frank H . Tooker, "The 'd.c. vari 3. The high cathode-heater voltage voItel"." Radio ~ TV News, April, 1958. The optimum values for the circuit l'ating (300 volts) and the 6.3-volt heater voltage permit use of the fila VIA ment transformer winding to supply external loads, as well. However, the high heater drain of the 6AS7G (2.5 amperes) reduces the current avail ;;; R5 able for other uses. Consideration might be given to the L1 use of a pair of 5AQ5's, with their heat l:1 ers supplied from the 5-volt winding usually provided in power transformers 5" for the rectifier filament. 6 1 The complete circuit, using ~ 6AS7G N rectifier tube, is shown in Fig. L If a "" different triode is chosen, R J ) R ., R s) and R4 should be selected so that the tube will be fully cut· off when the rheostat is VIB set at the zero position (maximum re sistance). In general, the portion of the plate voltage needed to be supplied to Fig. 1. Complete schematic of the variable power supply. (Continued on page 69)
AUDIO • MARCH, 1960 19 The Wood Panel That Talks
ABRAHAM B. COHEN ':'
A new loudspeaker system employs a heavy wood panel which is stiffly supported, but it reproduces low frequencies with a minimum of piston motion which results in low distortion and high electromagnetic efficiency.
N MODERN LOUDSPEAKER APPLICATIO~} the large packing crate type of en I closure has given way to the "book RADIATOR SUSPENSION DIPOLE CONTROL shelf" type of system; the "high-effi RESISTANCE ciency" driver has been superseded by the "low-efficiency" type; the complex I . ______REAR RADIATING baffle has been replaced by a simple r--- SURFACE sealed box. All these changes have I brought us to a new level of quality I otherwise, despite size reduction, these Fig. 2. Essential I small systems would not have been ac elements of the Bi I cepted. There is always room, however, Phonic Coupler. I VOICE COIL I for further progress toward higher pla I teaus of performance. The speaker system to be described in this article was designed with several SUPPORTING FRAME MAGN ETIC STRUCTURE goals in mind. F irst, of course, it was to set a new p lateau both of acoustic per formance subjectively and objectively. Second, it was to be mininaturized not only in aspect but in depth as well. Third, it was to overcome the preva ieal contoured field (for the lows) to a technical details are enlarged upon, at lently accepted philosophy that low fre beamed pattern so that low-frequency which time it will be recognized that quencies do not have stereo directivity, orientation would be as definitive as the this new dimension is literally one that and this was to be overcome by changing high-frequency field. can be measured by a physical yard the pattern of radiation from hemispher- In the consummation of these objec stick. The best way to describe the sys tives, we arrived at a final stl:ucture tem, shown in Figs. 1 and 2, is to illus which apparently flies in the face of tl'ate its differences from conventional * President, Advanced Acoustics, Inc., conventional loudspeaker design. The systems. The typical deep compounded 67 E. Centre St., Nutley 10, N. J . system is completely unbaffled, its vi pulp woofer cone has been replaced by brating element is literally as stiff as a a large 15 x 22 in. braced flat wooden board, and as flat as a pancake. This is, panel, which is the main acoustic radia of course, a real far cry from the preva tor. The "long throw"-usually about lently popular, very loose, deep conical ~" travel-excursion of the conven structure, in a tightly sealed box. In tional low-efficiency woofer has been re the early stages of the development of placed by only microscopic motion of this speaker, the question was asked, the large radiation panel. The low level "What kind of a speaker is it and in of elect1'ical damping in the low-effi what type of enclosure does it operate~" ciency systems due to the incomplete The answer was very simple: it is linkage between the voice coil current neither a speaker, nor an enclosure, and in the overhanging coil and the mag there it rested until it could be un netic gap has been replaced by the maxi wrapped. We have now unwrapped it, mum possible coil-to-magnetic-circuit and its design details are now available. coupling factor without loss of linearity since the radiating panel motion is so Low Frequencies From Stiff Boards microscopic in magnitude. The low level However, before we go into these de of acoustic radiation efficiency, typical tails, it would be worthwhile first to de of a 12-in. speaker with an effective pis scribe the system in its completed form ton area of 75 square inches, has been and to illustrate its new characteristics superseded by high acoustic radiation as an acoustic radiator, which both efficiency of the 330 square inch flat mathematically and physically add a panel radiator. The closed sealed box has new spatial dimension even to mono been replaced by a completely open channel reproduction. Now, lest this frame supporting the flat panel vibrat Fig . 1. The Bi-Phonic Coupler, measuring ' seem a "sales pitch," the author begs the ing structure, a completely unbafHed 18 by 24 by 4Vz in. over-all. reader to reserve judgment until the radiator. On this last item, we have with-
20 AUDIO • MARCH, 1960 out fail been asked at every preview how board hammer strikes a stretched string its vibrations to the back panel via the it is possible to get 30 cps response from causing it to vibrate at its fundamental sound post which rigidly and mechani- an unbaffled speaker. The answer comes frequency and its many harmonics. Now first in the listening, and then in the we know that if the string were in open ~:~I~h:o~:l~:'~u~~~;O~!l;Oo~~:oa:k;:i~~ mathematical analysis of the free radiat space it would not create much sound, holds the front and back together. This ing system. anymore than does a tuning fork unlesR results in both front and back of the brought in contact with some resonator instrument both being energized as sound device. In the instance of the piano, the low-Fre~~ ency Musical Instruments radiators with very complicated phase string that is struck is stretched tightly relationships between them. In effect, On the matter of the mathematical over two supports in direct communica then, the bass viol is essentially a double treatment of the system we will in due tion with the massive metal frame that vibrating panel structure without any time ta~e it up in detail. There are, supports the wood sounding board in acoustic baffling to prevent front-to-real' however, 'some interesting thoughts that the body of the piano. The vibrations of wave cancellation. In addition to the ab should be explored concerning the man the struck string energize the sounding sence of any baffle structure, the vibrat ner in which low frequencies are origi board putting it into vibration with the ing panel structure is itself a solid heavy nally P1'ocZuced by musical instruments string. It is this massive taut "dia rigidly secured panel compared to its themselves, and how the conventional phragm" which radiates the sound wave conventional loudspeaker counterpart. loudspeaker that is called upon to repro originated by the struck string. Now this Despite its un baffled condition, and the duce these bass notes deviate so radi radiator is not a loosely suspended light "infinitely" stiff suspension of its vibrat cally in its philosophy of design. Con diaphragm. It is practically an immo ing panels, the bass violin' is productive sideration of this problem led to the bile pinned down wooden plate. It is not of the most respected low frequency design principles behind the Bi-Phonic boxed in to prevent front to rear radia notes in the musical repertoire; yet its Coupler. tion. It is completely open to space on vibratile parts appeal' practically immo If we were to examine some of these both sides, allowing both sides to radiate bile-when at the same time to repro well recognized bass-producing musical equally. The radiated sound due to the duce these notes the conventional loud instruments we would find that instead mechanical flexing of this sounding speaker employs a boxed-up violently of producing sound by means of loosely board is not imprisoned on one side-it vibrating element. suspended piston devices, they use is not boxed in, but free to radiate from It was primarily through a feeling tighly secured wooden or metal panels, both sides. In fact, the piano lid itself that despite the profoundly exceUcnt or tightly stretched membranes. Sec in its raised position, does more than performance of some of our present ondly, rather than being "boxed in" de just reflect the sound out to the listener. loudspeaker structures, that reproduc vices with solid non-vibrating acoustic It is also sent into sympathetic vibration tion more nearly duplicate of the origi restraining walls, they are completely by the sound hitting it from the sound nal could be obtained if our reprodueers free radiators with no acoustic baffling ing board; it vibrates as an independent were themselves built more nearly hke or damping other than that provided by panel (but in synchronism with the our musical instruments, based on the the acoustic radiation upon the driving original note) completely unrestraincd above analysis. system itself. We have in reference such on either side: unbaffled, unboxed, but instruments as the piano, the string fam yet an efficient low-frequency radiator. ily, and the percussion family, from The bass viol is another instrument Stereo Advantage of low-Frequency where stem most of the orchestral bass which reaches far down into the lower Dipole Operation notes. A beautiful example of these stiff acoustic spectrum, and deviates in some From this study then, emerged ihe plate, unbaffled musical instruments is highly thought-provoking ways from basic "Bi-Phonic Coupler." As we ob the grand piano where in the bass end commonly accepted "enclosure" practice. served in detail above, the essential char of the keyboard the acoustic spectrum It may at first glance seem that the body acteristic of the low-frequency musical goes down to 27.5 cps. of the bass violin is a resonated vented instrument is the (a) heavy} (b) dgidly In this discussion we should not think box. However, mathematical analysis suspended} (c) unbafJled vibmtile panel. of the usual resonators of musical in will show that the open "f" holes in Of these three aspects of design, the un struments as baffles. In our acoustic the body of the instrument are far too baffled characteristic promised to be most terminology, baffle is specifically meant small to resonate the large physical vol intriguing on the basis that the spatial to imply an acoustic deterrent to the ume of the instrument for the lowest fre radiation pattern from an unbaffled destruction of the wavefront from one quencies it reproduces. Applying the source is not circular, but a "figure 8" side of the loudspeaker by the wavefront cosine function. As shown in F ·ig. 3, a. standard resonator formula, calculat.ions from the other side. In the case of the completely baffled radiator produces es will show that the first cavity resonance sealed box, the piston rear wave is com sentially a hemispherical radiation pat of instrument to be about an octave 01' pletely impri.soned. In the vented box, tern for low frequencies. However, when more higher than its first fundamental the pison rear wave is angularly accler unbaffied, a loudspeaker piston acts as a ba.ss note. Even were the body volume era ted in phase so that it emerges from dipole radiator with characteristically and "f" hole areas compatible to reso the vent in phase with the front wave; doubled looped, or "figure 8" pattern, front wave deterioration is thereby re nate to the low frequencies, the body even at, or shall we say especially at, duced. In the true infinite baffle, com walls of the instrument are themselves low frequencies. When this fact is as· plete front-to-back radiation separation comparatively vibratile, not at all flex similated, th'ere will come the realization is obtained by the wall holding the ure free as is required by good standard that this latter condition is one that speaker, with the piston radiating inde acoustic enclosure practice of "at least should be highly desirable to overcome pendently into the two "half space" ~ -in. plywood, rigidly braced, or 'sand the "spread eagle" effect of low-fre areas on either side of the wall. These filled' walls." In short, the body of the quency ambiguity in stereo reproduction. are baffles in the true acoustic sense, and bass violin is not primarily a resonator; This low-frequency ambiguity has, of are not primarily resonators. it is a driven (double) panel structure. course, been put to use in creating stereo With this simple statement concerning The strings impart the vibrations to the systems of the satellite or outboard acoustic baffling we may return to the bridge, which energizes the entire belly speaker type where the direction of case of the grand piano. The piano key- panel. The belly panel in turn transmi.ts origin of the middle- and high-frequency
AUDIO • MARCH, 1960 21 tional loose cones when reproducing the bass tones. . This much we did know, that no mat t ter how we redesigned the loudspeaker t we weren't going to rewrite any of Mother Nature's laws of physics, we were' only going to re-interpret them to our better advantage. Now, this simply means that if a 12-in. dfaphragm has to trans verse a given axial distance to produce a certain sound pressure at our ear drums, (A) we can't simply say to the piston, "Stop vibrating, but mind you keep developing ttJ,e same sound pressure at our ears." This would mean the rewriting of our . acoustic laws, for which we are as yet t inadequately prepared. However,. we·can (8) look at the diaphragm- with the inten-, tion of redesigning it so that even though Fig. 3. Whereas baffled pistons produce hemispherical low-frequency patterns (A), baffled dipole' systems (B) produce directional fields improving low-frequency its vibratile motion is decreased, its. orientation. . ~ound power output may still be re tained. There is a standard formula in components of the bass notes created an ture which it is given. Of course, the our art which, on the face of the p'l'ob apparent source for the basic low-fre- shape of the conventional cone is gOY lem, makes it fairly simple to maintain a quency notes themselves. This system erned by the simple fact that to give the given fixed sound pressure at a distance "works" because the low frequencies paper strength and rigidity for large as the size of the vibrating piston· from baflled speakers are so spherically woofer excursions it just had to assnme changes. After some mathematical ma diffused, that they are joined to the dis- the deep conical shape. In fact, the more nipulation, the final succinct and simple embodied middle and higher frequencies excessive the excursion of the dia formula for the soundpower output in in some other part of the room. These phragm, the deeper does the paper cone watts of a vibrating piston is given as' outboard stereo systems 'work, but there have to be to maintain its stability. As p = 'l'ma X 10-7 where X is the piston dis are profound problems of space phasing a matter of fact so prevalent is the placement and 'l'ma is the mechanical re between the diffuse woofer radiation and break-up characteristic of conventional sistance seen by the vibrating piston. the woofer harmonies originating else- pulp diaphragms that many a commer This tells the simple story that the where in the room. To overcome these cialloudspeaker design as actually predi greater the piston displacement the more problems where space permits, com- cated upon lack of piston action, through the power output; it also tells us' that pletely identical systems are used for which defection spectrum band separa the greater the resistance 'l'ma seen by both stereo channels. Though we may tion is obtained between high frequcn .. the diaphragm, the more power can be have overcome space phasing problems cies and low frequencies. This condition transferred from the diaphragm to the between component harmonics of low is usually referred to as "mechanical air load responsible for the resistance. frequency tones we have not overcome crossover." Well, for obvious musical the basic low-frequency ambiguity due reasons, whereby a paper cone does not to the hemispherical radiation and dif- find existence, and from years of field Baffle Conditions Affect Piston Radiation fusion of lows from completely baffled experience with cone break up, the first Now this radiation resistance is not a speaker systems. The unbaflled radiator, step that had to be taken to return to simply written quantity. It is a function however, with its sharpened "figure 8" basic musical acousties seemed to eall of the size of the piston, the frequency pattern for all frequencies, including the for retiring the paper cone. of operation, and the condition of very lowest, may serve to eliminate this For both decor and musical instt.'u baffling. This relationship is shown in low-frequency directional ambiguity not ment design the choice of the radiator Fig. 4 for three general conditions: (A) only for stereo reproduction but for construction was a wooden panel that where a piston is vibrating in the plane monochannel reproduction as well. would be both functional in a musieal of an infinite baffle, (B) where it is Thus, for purposes stemming both sense, and be intrinsically decorative so vibrating in an infinitely long tube with from a desire to simulate more nearly that it could take its place in the home the piston terminating one end of the the basic structural operation of bas~- without being hidden behind a grill tube, and (0) where the piston is com producing instruments, and at the same cloth. From all considerations it seemed pletely unbaffled. Curve A is frequently time to gain a stereo directional advan- that a flat wooden panel vibrator ,vas seen in the literature, and equally as !age-the unbaffled radiator approach called for since we could, through proper often applied in practice. To clarify was specified as one of the prime design bracing, (such as the bass bar beneath later discussion however, a few words parameters. We were now faced with the body of the violin) give the panel about curve (B) in this figure would the problem of choosing the diaphragm structural rigidity even though flat, and be germaine. While the values represent structure itself, and the determination at the same time give it a musical in the resistive loading upon a vibrating of its size to produce the necessary bot- strument type of finish. A step to be piston at the end of an infinitely long tom of acoustic response. taken simultaneously with putting the tube, it may be applied to any type of Radiation Panel Design paper cone out to pasture was one structure where the rear radiation of whereby the actual sound reproducing the piston is completely absorbed but . The starting point of the diaphragm . element for all practical purposes would where the front face of the piston is not design lay in doing away with the fra- stand "still" while it is radiating, like integral with any other baffling surface gile paper cone-such a device just does the sounding board of the piano or Lhe not exist in musical instruments-neither body panels of the bass violin, rather sharing the same plane. Beranekl says
in terms of the paper pulp from which than flex back and forth over compara 1 Leo L. Beranek, "Acoustics," page lOS; it is made, nor the shape of the struc- tively great distances as do the conven- McGraw Rill. . . .
22 AUDIO • MARCH. 1960 on this point: IIIn many instances sound Converting 40 cps into terms of wave This, of course, implies a completely IIno is radiated from a diaphragm whose ,length in centimeters (0 ="AI) we get throw" voice coil, in contrast to the rear is shielded from the front side by 860, and converting the ll-in. (effective) "long throw," which leads to some in a box or a tube. If the box does not ex diameter piston to circumference in teresting and important discussions con- tend appreciably. beyond the edges 9f _ centimeters we get $7.6, so that . th~ cir ~ . cerning efficiency and transient response. the diaphragm, its performance may be cumference/wavelength ratio becomes But to continue our thesis concerning estimated by comparison with that of very nearly 0.102; this, in turn, yields the unbaffled radiator, we have seen that a rigid piston placed in the end of a a radiation resistance per square centi a small sealed box is by no means an in long tube." Somewhat later in the same meter of 0.210, considerably removed finite baffle in an acoustic-radiation reference,2 liThe magnitude of the front from the 42-ohm maximum! How can we sense. The radiation from the piston radiation impedance depends on whether raise it to a more optimum value'f Sim falls back and folds around the box, the box is very large so that it ap ply ( !) by increasing the speaker size to which completely alters the character of proaches an infinite baffle, or whether let us say 15 in. (with an effective piston the load upon the diaphragm. Actually, the box has a dimension of less than 7.6 . diameter of 14 in.). Proceeding through for a given frequency below the transi cubic feet. . . in which case the radia~ the same arithmetic as before for this tion point where the piston circumfer tion impedance is approximately that new size of piston, again operating at ence to wavelength ratio is less than 2 . of Jl piston in the end of a long tube." 40 cps we arrive at a O/"A ratio of 0.13 (see Fig. 4), the radiation impedance of Similarly, Olson3 II • •• the .radiation re which yields a radiation resistance of the boxed piston is essentially half· of sistance for a vibrating piston in an ·0.378 ohms per sq. cm. as against a value that when placed in a true infinite baffie, infinite baffie is two times the radiation of 0.210 for the ll-in. piston. -Now, with essentially half of the radiated resistance of a vibrating piston located multiplying these unit values by the re power of the latter. In the case of the in the end of an infinite tube." spective total areas of their pistons we small closed box, the piston radiates Curve (C) of F i g. 4 is seldom con get 0.378 x Jt x (7 X 2.54)2 for the 15-in. into a "full spherical" space of 411: ste fronted in practice, for one hardly ever speaker and 0.210 x Jt x (5.5 x 2.54) 2 for radians3 by diffracting around the box. thinks of operating a speaker in an un the 12-in. unit, the ratio of the two being In the case of the true infinite baffle,· tIre baffied condition. But this particular 2.8. In other words, the 15-in. unit pro baffle divides space into two parts with parameter is precisely the set of con duces better lows than the 12-in. one be the piston radiating into one of these ditions with which we will be dealing in cause the total radiation resistance that "half spaces" while at the same time the the direct explanation of the system. the former sees is close to three times baffle creates an image of the sound But before we get down to consider as great as that seen by the latter. source placed within it to be re-radiated ing this new design in detaP., we must Now, lest it seem that we have dwelt along with the original sound power thus lay some groundwork by discussing too long on some of the simple facts con doubling the total sound power, as some interesting facts concerning the cerning basic loudspeaker performance, against that obtained from the small box first two conditions. Both of these situa we wish to explain that the design of type of radiator. tions are relatively common in practice. the bi-phonic coupler is specifically based Whenever a loudspeaker is mounted in on modifi(lations of the above type of Un baffled Load Upon the Piston a wall or in the face of a large cabinet analysis. Weare concerned with de In full recognition of these baffle com where there is a large flat space coupled termining the parameters of the design plications and configurations, and fur directly to the loudspeaker piston plane of an unbaffled radiating panel which thermore whetted by the desire to (and where there is no front to back will provide the desired low-frequency sharpen the low-frequency radiation di radiation) then condition (A) holds. For response. A rider to this parameter is rectivity, we determined to free our a given size of piston and for a· given that the panel be of such a size that selves of the baffle problem entirely, and frequency we may readily find the radi when reproducing the propel' frequency the only way to accomplish this was to ation resistance into which the outward at a desired sound pressurc, the motion provide a completely free-space piston face of the piston work. It will be ob of the panel be -reduced to a value that vibrating without any baffle restriction served, for instance, that when the cir the hand can feel, but the eye not see. whatever. Now off hand, there should be cumference of the piston is equal to a virile chorus of objections that such a twice the wavelength being radiated, system just cannot work, that doublet that the radiation resistance per unit radiation would immediately cancel out 4 area, curve (A), just about reaches the 1//,. all radiated power for those frequencies 2 I -- where the wavelength was large com levelling off maximum of 42 ohms per ...: [1/ pared to the piston size. Certainly, there square centimeter, above which fre ~ l, I quency the radiation resistance remains ... 4 are valid. objections, but only insofar Z 1/ I fairly constant. We are at present in ::::l 2. 1 liS they may be numerically verified. The I C terested in the condition that prevails ii! fact of the matter is that from the set w liB of curves of Fig. 4, it is possible to put below this settling down plateau, since U .4 Z a straight edge along anyone horizontal it is in this toboggan-slide area where ~ .2 1 II I ;;; I level indicating any desired unit radia '"w ,I most of our loudspeaker problems arise. Cl~___ :.2___ tion resistance value and pick off as at '"z For cxample, consider a 12-in. loud o .04 ~ ~ points (1), (2), and (3) the circum 1 ,fill••• .}. I•••• ~ II speaker. We will stretch a point and ~ .02 ll'" ference-to-wavelength ratio for a piston ;:; 1 I I credit this 12-in. speaker with a piston ..: I I :/1/. I in an infinite baffie, a second value for of ll-in. effective diameter. Now, put it '" I .004 ~I I ·t:/it I one in a small box, and a third value for into a true infinite baffle and feed it a . •01 .05 0.1 0.5 1.0 10 one. completely unbaffled. From these signal which, from today's standai'ds,we . values we could then determine, for Ii CIRCUMfERENCE should expect it to really .repro!Illce. WAVElENGTH fixed frequency, a rising progression of different piston sizes to produce a given 2 Ibid., pages 215, 216. . sound pressure for the· conditions of in 3 Harry F. Olson," AcousticaZ Engineer. Fig. 4. Radiation resistance for pistons ing," page 98. D. Van Nostrand 1957 in (Al infinite baffle, (Bl small box, and finite baffiing to no baffle at all . . edition. (el free spcice. (Oontinued on page 65)
AUDIO • MARCH, 1960 23 Audio Engineering Society
SEVENTH ANNUAL WESTERN CONVENTION AND EXHIBIT
HE 1960 VVESTERN CONVENTION of the Audio Engineering trical application and which predate vacuum tubes. Many Society will be held March 8th to llth at the Alexandria other museum pieces have been loaned for the exhibit by THotel, 210 West 5th Street, Los Angeles, California. AES members and friends throughout California. The In addition to the presentation of the technical papers entire display has been planned as a representation .of the listed below there will be the customary exhibit of profes periods and progress of the recording and reproduction of sional audio equipment, silently displayed, allowing engi SOlIDd. neers to see and evaluate new methods and devicEs under In order to defray expenses, there will be a registration suitable testing conditions. fee of $1.00 for members and $3 .00 for non-members. Upon A special attraction at the convention this year will be registration, a lapel card will be issued which will admit an exhibit of early sound and recording equipment. The holders to all exhibits and technical sessions. For non New Almaden Museum, run by Douglas Perham, has loaned members p lanning to attend the exhibits only, the admission the Society many historical pieces of equipment for display. fee will be $1.00. Among them are the first magnetic phonograph pickup; The symposium on Friday night, March llth, will be one of the first amplifier-loudspeaker combinations, made open to all previous registrants free of charge. There will by Telemegophone; an early Victor His Master's Voice disc be a $1.00 admission charge for all others. phonogra ph; and what is believed to be the first commercial Registration opens at noon on Tuesday, March 8, on the radio broadcast microphone, a carbon unit manufactured by second floor of the Alexandria Hotel in time for the first Western Electric. In addition to these, there will be on session which begins at 1 :30 p.m. Many of the forty papers display a very early Marconi loudspeaker, an Edison Gem have nevel' been presented before and covel' the most recent recorder, and two mechanical amplifiers designed for elec- developments in the audio field.
Tuesday, March 8. Performance Crite·ria. and Design Consid Modern Bec(}rding Studio Techniques. eration for Language L a boratory Sys DeWitt F. Morris, United Record ing 1 :30 p.m. MAGNETIC ItECORDING tems. Corp. E. H. T aylor, DuKane Corp. Recording Studio Control Boom Pacilities Walter T . Selsted , Ampex Corp., Chair of Advanced Design. man. Milton T. Putn am, United Record in g A Multichannel La.ngua.ge Laboratory 1 :30 p.m. AUDIO CIRCUITS. Corp. Beco·rder. I R alph H. Sogge, Magnasyn c Mfg. Co. Norman Chalfin, H u ghes Aircraft Co., Ltd. Chairman. Becent Achievements in Missile-Borne Automa.tic Phasing' of Stereophonic Sig Friday, March 11 . Magnetic Tape Recorders. nals. 9:30 a.m. ACOUSTICS, REVERBERA Mark M. Siera, L ockh eed A ircraft Corp. B. B. Bau er, A. A. Goldber g , a n d G. D. Professiona.l Becorder Design, Service, Pollack, CBS Laboratories . TIONS AND AMBIOPHONIC TECH .and Mainterul.nce. Pra ctical T ransfo·rmerless Complemen NIQUES. J ames I. Stu ltz, Ampex Corp. tary Synunetry Audio Output ampli The Multichannel Recording for Master fiers. Pell Kru ttschnitt, Capitol Records, ing' Purposes. W. F. Palmer and A. Finneault, Sylva Chairman. Mort F ujii, George Reh k la u, and J ohn. nia Electric Produ cts Co. Xndustrial Acoustics-A Survey. McKnight, Ampex Corp. A Signal-Biasing' Output T ransformerless . Dr. Vincent Salmon, Stanford Research Synchronized Se:parate Sound for the TV Transistor: Power Ampli1ler. I nstitu te. Tape Recorder. . Richard C. Heyser, California I nstitute The Unconventional Use of Conventional Ross H. Sn yder, Ampex Cor p. of Technology. M a terials to Obtam Highly Desirable A Low Distortion Volume Expander for Results in Auditorium. Acoustics. Home Use. Ludwig W . Sepmeyer, Systems Devel R. J . Matthys, Minneapolis H oneywell opment Corp. 7:30 p.m. MAGNETIC AND DISC RE Regulator Company. Practical Sound Reinforcement for CORDING. A New Bias Method for Powe·r Amplifiers. Churches. George Brettell, Ampex Corp. Lau ren Matson, A u d io Consu ltan t. Ross H. Snyder, Ampex Corp., Chair Loudspeaker Response in Rooms. man. William B. Snow, Consulting Engineer. Audio Message Synthesis. L ou is MacKen zie, MacKenzie E lectron 7:30 p.m. AWARDS BANQUET ics, I nc. New Techniques in Miniature Recorders. Thursday, March 10. · 1 :30 p.m. AUDIO MEASUREMENTS AND Walter Stancil, S t ancil Hoffman Corp. 1 :30 p.m. LOUDSPEAKERS, ENCLO ANALYSIS. Ma.x1m.um. Peak Velocity Capa bilities of the Disc Record. SURES, AND ACOUSTIC DEVICES Ward Widener, Ampex A udio, I nc., J. W . Staffor d, Westrex Corp. Dr. Vincent Sal mon, Stanford Research Chairman. The Use of 3S-nun Sprocket-Type Mag Institu te, Chairman. Some Phenom ena. of Underwater ACOUStic :'a~ter~~lm in Recording Phonograph Stereophonic Earphones. Propaga tion. B. B. Bauer, CBS Laboratories. Dr. H. G . Ferris , H u g h es A ircraft Co. John G. Frayne and J. W. Stafford, An ElectrO-Pneumatic Loudspea.ke·r. The C(}nverg ence Zone Effect in Acoustic Westr ex Corp. John K. Hilliard, Altec Lansing Corp. Transmission in Deep W a ter. 3S-nun Sprocket-Type Magnetic PUm Electrostatic Earphones. A L u bell, H u ghes Aircraft Co. Compared with One-Quarter Xnch M a g Walter T. Selsted, Ampex Corp. Use of High-Speed Digital Computers f or netic Tape. A New Extended-Ra.ng'&-8-Xnch Loud- . R a y Tracing' of Underwa ter Acoust ic Fran k G. Lennert and John G. speaker for Minimum. Volum.e Enclo Paths. McKnigh t , Ampex Corp. sures. Don A. M u rphy, H u ghes Aircraft Co. Acoustic Xnstrum.enta tion for M easure ~g:;;'~~d A. May, J ames B . L ansing ments in the Minute-Man Missile Silo. A N ow High-Pr equency Loudspeak er. D. N. Keast, Bol t Beranek & Newman, Wednesday, March 9. Earl Matsuoka, University Lou dspeak Inc. ers, Inc. Precise Mea surement of Large Dynamic 9:30 a.m. STEREO AND MONOPHONIC Response Characteristics of P a ssive and REPRODUCTION. Active Audio Networks. David S. Cochran, Hewlett-Packard Co. J ohn G. McKnigh t, Ampex Corp., Chair 7 :30 p.m. STEREO BROADCASTING The Advantages of the Pea k-l:ndica ting' man. AND STUDIO INPUT SYSTEMS. Volum.e Meter Over the Standa rd ASA Synchronous Audio-Visual Display Tech Moving'-Coil Volum.e Mete·r a.s Applied niques. Sidn ey P. Alder, Minnesota Mining & to Becording. J oh n T. Mullin, Minnesot a Mining & Mfg. Co., Chairman. Mfg. Co. Stephen F . Temmer, Gotham A u dio De A Plexible Combina.tion 3-Channel Stereo velopment Corp. Qua.l1ty Control Stereophonic Beview Mi,?rophone and Rerecording' Cons(}le. Equipme·nt. rnh~.llP C. Erhorn, Audiofax Associates, Pell K:u ttschnitt, Capitol Record s , I n c. Elimina.tin.g the Stereo Seat. L-300-D Compressor Limiter Expander. 7:30 p.m. SYMPOSIUM (See note below ) J ohn Mosely, A udio Fide lity Inc Donald F. Dimon, Halex, I nc. Auditory Transmission of Inforin.a.tlon An: Advanced Audio Console for TV Th:n:e;~~ Xndustry-xts Past, Present without Conscious Awareness. Broadcasting' • L awren ce Ze itli n, D unlap and Associ T h eodor e B. Grenier, American Broad Harry L . Bryan t, Radio Records, I nc., a t es, I nc. castin g Co. Pres., AES, c h airman. JE:
24 AUDIO • MARCH , 1.960 $12950 Slightly Higher In the West
WITH TWO REVOLUTIONARY NEW FEATURES (1) Pilot's exclusive Simpli matic Test Panel- Now you can balance your output tubes using your speaker system as an indicator . .. No need for any external meters . . . (2) Pilot's Stereo Plus THEMI1;240 provides a center channel signal-the sum of A + B-to solve the' "hole-in-the-middle" problem. Designed and engineered to professional standards, the Pilot 240 includes these addi tional features:
• 4 independent tone controls - Exclusive Pilot TroLoK mechan· • Exclusive PILOT automatic shut-off switch enables .the record ically locks the Bass controls together and the Treble controls changer, at your option, to turn off the complete system after together, at your option, to permit simultaneous (ganged) ad· the last record has played. justment of Bass and Treble for both channels . . • Provides automatic cancellation of undesired vertical response • Three pairs of high level inputs for permanent simultaneous of a stereo cartridge when playing a monophonic recording, with connection of FM·AM tuner, Multiplex Adapter and Tape Recorder. Mode switch set to Mono-and eliminates necessity for separate • Two pairs of low level inputs for permanent connection of record Stereo·Mono switch. changer and turntable. • 11 Front Panel Controls - Input Selector, Mode (including • Non-shorting inputs throughout permit recording and playback Stereo Reverse), Dual TroLoK Tone Controls (Treble Channel A. using a permanently connected tape recorder without short cir· Treble Channel B, Bass Channel A, Bass Channel B), Stereo cuiting the tape recording signal, or the necessity for changing Balance, Master Volume, Speakers: Automatic Shut·off, and of plugs. Loudness. • Direct tape playback facilities are provided by connecting the • Specifications - Power Output: 30 watts total; 15 watts per tape head to one of the phono inputs. NARTB tape equalization channel, music power (in accordance with proposed IHFM Is provided at calibrated pOSitions on the tone controls. standards). Sensitivity for full output: 3 mv for phono record • Amplifier terminals permit you to connect a set of extension changer, phono turntable; 110 mv for FM·AM, mUltiplex, tape speakers in another room. Front panel Speaker switch con· recorder. Harmonic Distortion: 1%. Hum and Noise: 80 db veniently selects either the main or extension system, or both. below full output. Frequency Response: ± 1 db 20·20.000 cycles. • Electronic Crossover feeds low frequencies to Channel A and • Dramatic design - brushed· brass escutcheon with 24K gold· high frequencies to Channel B for monophonic bi·amplifier use. plated frame and heavy duty knobs. Supplied complete with • Loudness Switch modifies the frequency response for enhanced black vinyl·clad steel enclosure. listening at low sound levels. • Price - $129.50 including enclosure. Slightly Higher In the West
WRITE TODAY FOR THE COMPLETE PILOT STEREOPHONIC COMPONENT CATALOG
PILOT RADIO CORPORATION. 37-04 36th STREET. L. I. CITY 1 , N. Y.
AUDIO • MARCH, 1960 25 Hi~Fi System with a Roof
Twenty-five ton stereo loudspeaker enclosure proves that its owner and designer prac tices what he preaches-and ends up with superb sound and a truly magnificent decor.
NE OF THE HIGH POINTS of our recent trip to the two West Coast hi-fi shows was an opportunity of seeing Oand hearing the installation pictured on the cover. Although we had already seen pictures, we are of the opinion that no sound installation can be judged solely from photographs, so we just had to see and hear it. Since we had committed ourselves to use the photo on the cover of AUDIO, it was quite simple to wangle an invitation. FAbQ.IC. COVt.I2INC. ON To begin with, the house itself is located on a hilltop in PLYWOOD FQAME Cowan Heights, a section of Santa Ana, California, with a 270-deg. view which extends, in one direction, to the islands some 25 miles offshore. The two-acre site precludes next door neighbors-always a disadvantage to dyed-in-the-wool hi-fi enthusiasts, of which group Dr. John K. Hilliard is practically a charter member. In his spare time he is Vice FI"E"""E ------President and Director of Advanced Engineering of Altec
Lansing Corporation, whose main offices and plant are HINC.e:D PlYWOOD CUT -OUT FOI2 SPo.KU~ -----III-H located in nearby Anaheim. ~D rH -muM!:! 5CJ«W~ 'MJ!N The house, designed by architects Ramberg & Lowrey, g..,j ~D f'Oo&lTION fits the location perfectly, and the living room is the center of attraction-both to the eye and to the ear. Dr. Hilliard planned the basic dimensions of the room, 30 feet across the fil"eplace wall, tapering down to 20 feet at the opposite end so as to have no parallel walls. The beam at the top of the fireplace is 20 feet high, while at the opposite end, some 40 feet back, it is only 16 feet high, thus continuing the non-parallel configuration. The fireplace-loudspeaker enclosure structure contains 25 tons of stone, with each
speaker section comprising 300 cubic feet. The "grille cloth" extends from floor to ceiling and is pale gray Belgian linen, the same as the draperies in the room. The size of the speaker grilles completely eliminates the feeling that there are two loudspeakers-one of the deterrents to good stereo listening, for if you can see two speakers, you can hear two, and they do not blend into a wall of sound as a good stereo system should. No trace of this sensation is felt when listen ing to this system. The interior of each enclosure is 4 feet square by about 18 -feet high, giving an almost true infinite baffle. The drawing above shows the internal arrangement, while the photo at the left shows the physical appearance of the speaker panel. Each channel consists of two Altec 803B . low-frequency drivers, one Altec 802D high-frequency driver on a 511B sectoral horn with a 500-cps crossover, together with an N-500D network. The electronic complement con sists of Altec 445A stereo preamp, 345A stereo power am plifier, and 306A AM-FM tuner, an Ampex 960 tape repro ducer, a Garrard 301 turntable, and a Pickering 196 Unipoise arm and Fluxvalve. All of these units are installed in a closet at the left side of the room. In addition, five Altec 408A speakers driven by a monophonic Altec 355A amplifier are located in the lanai, workshop, and bedrooms for "ordinary" listening. The superb reproduction from this "uncramped" stereo . system has been heard by a number of local and distant architects of fine homes, notable among them being Frank Lloyd Wright, Jr., who presently is designing similar sys tems in several homes for his clients. Unlike the proverbial ~obbler who has holes in his shoes, Dr. Hilliard-in the high fidelity business-has the best possible system in his own home. . .IE
26 AUDIO • MARCH, 1960 CP-2 POWER SUPPLY Custom matched to each microphone
Designed to ' meet exacting professional standards where utmost performance, dependability and fidelity is essential. The exceptionally smooth frequency response of 20-20,000 CPS * is completely free of resonant peaks and dips.
U~i-directional and omni-directional: Mcrximum front to back sensi· tivity of more than 15 db provides unequalled Cardioid pattern. Output Impedance: 200 ohms balanced Output Level: Uni directional - 50 db Omni·directional -52 db
* Actual anechoid response curve and descriptive brochure available upon request.
SO~y CR-4 RADIO Wireless MICROPHONE The Sony model CR-4 is a complete professional wireless microphone with an all-transistor ·FM transmitter, a dynamic lavalier microphone and an 8-tube FM receiver. TRANSMITIER RECEIVER • Self powered with 2 inexpensive miniature • Small size and lightweight, very attractive batteries . for desk use • Detachable small dynamic microphone • High sensitivity and low noise • Can be held, used as lavalier, or concealed • Squelch circuit for elimination of inter· • Flexible, detachable antenna ference • No FCC license is required , • Neon light for selective tuning • Built·in monitor· speaker with volume control
For free descriptive literoture ond name of nearest franchised dealer in U. S. write:
5UPERSCOPE, INC., Audio Electronics Division/Sun Volley, California. INCORPORATED
AUDIO • MARCH, 1960 27 Maintaining Frequency Response • In Recorders If you are not satisfied with the frequency response you are getting from your tape re corder, this article may tell you why and it may also tell you what you can do to correct it. HERMAN BURSTEIN ':'
IN TWO PARTS-PART I
s IS USUAL in discussions of fre TAKEUP REEL-TENDS TO ROTATE ' AS SHOWN, quen cy response, we are concerned EXERTING FORWARD TENSION ON THE TAPE A with response that is smooth, f ull at the low end, and maintained substan ACTUAL ROTATION OF tially to the upper limit of the audio SUPPLY REEL DUE TO range-at least to 12,000 cps and prefer ACTION OF CAPSTAN --L ably to 15,000. In the case of tape re cording and playback, the greatest prob lem is to preserve the high f requencies, ~~ and so it is this particular aspect of the ~V subject of frequency response that will figure largest in the f ollowing discus DIRECTION OF_J-_r sion. P reservation of the upper audio TAPE TRAV,El rangc is relatively more difficult in tape r ecorders than with other elements of an audio system. Tbis is particularly true when tape speed is 7.5 ips or less. HEADS W hile a tape machine may pcrform TAPE wcll initially, its f requency response may
* 280 ;I'win Lane E ., W an 't agh, N .Y. Fig . 2. Use of tape tension to achieve firm contact be twe en the tape and the heads.
deteriorate with age, use, or mishap . realm. When maximizing f requency re Maintaining f requency response as it sponse in the sense of extending the should and can be requires care on the range to 15,000 cps or so, sacrifices may owner's part. On the other hand, fre be required with respect to distortion, quency response of a tape machine may signal-to-noise ratio, or both. Accord not initially be all that it should be. ingly, the problem may be of finding a Alcrt to this possibility, the purchaser suitahle compromise among conflicting is in a p osition to reject a p articular considerations, namely treble response, model or a p articular unit of a given distortion, and noise. model that cannot deliver a desired standard of performance. Through com Tape Spe ed prehension of the various factors that Frequency response is closely associ enter into a tape machine's frequency ated with tape speed. In recording, cer response, the prospective purchaser or tain losses occur that increase with f re the present owner maximizes his chances quency, and the slower the tape speed of obtaining suitable frequency re the greater the loss at any given fre sponse. quency. In playback, ther e are losses as Fig. 1. Erosion of the gop of a tape head At the same time, one obtains very sociated with the playback head that due to abrasive action of the tape. little for nothing in the electronics similarly increase with frequency and
28 AUDIO • MARCH , 1960 Between this adjustable baffle and its mate below, both directing sound from matched 7" speakers, is the most unique stereo tape system on the market. It's just one single piece (only the lid comes off) that lets you enjoy all the benefits of stereo sound. Records stereo live, from records, or off -the-air; plays new 4-track and earlier tapes. This marvel is the New Ampex Monitor 970 Stereo Recorder I Player from the world leader in the field of magnetic recording. This new unit has separate record and playback pre-amps, dual-channel ampli fier; operates at two speeds, 3* and 712 ips.; can record sound on sound, monitor what you record as you're actually recording it. The price for the complete unit with its own gray luggage case is just $750, and you can buy it on convenient budget terms.
@19GO "MPEXAVOIOCOMPANY
AUDIO • MARCH, 1960 29 sufficiently narrow and linear for good treble response at the speed in use, the gap may widen due to head wear and thereby cause a noticeable fall-off in re production of high frequencies. The Fig. 3. Winding rapidity and extent of head wear depend the tape directly upon the following factors: from reel to reel 1. Head Construction. Laminated can reduce head heads generally wear better than non wear during re- laminated ones. winding. 2. Smoothness of the Tape. Depend ing upon the brand and quality of the tape and therefore upon the extent to HEAD COVER which the tape has been lubricated and polished, head wear will vary. Figure 1 suggests the nature of head wear due to become more acute as speed is reduced. inches per second, and G is the physical abrasive action of the tape; for visual For some time it has been possible at gap of the head, in inches, as specified clarity, the' effect of abrasive action bas 7.5 ips to achieve results consistent with by the manufacturer. been exaggerated in the drawing. the concept of high fidelity-namely, re To illustrate, assume that tape speed 3. Pressure of the Tape Against the sponse extending to 15,000 cps or at is' 7.5 ips and the gap of the playback Head. For good treble response it is im least to 12,000 cps. Quite recently, it has head is .00025 in. according to its manu portant that the tape and the heads appeared feasible to reach out to 12,000 facturer. Then f=7.5/(2 x .00025)=15,- maintain intimate contact. However, the cps or better at 3.75 ips as well, and 000 cps. At a tape speed of 3.75 ips, pressure required for close contact re even 1.875 speed has been gaining a however, the upper response limit for sults in friction as the tape moves past place in home use. While it may be ade tbis head would be only about 7500 cps. the heads. Thus the pressure should be quate for moderate quality reproduction It is therefore apparent why gaps con just enough to maintain good contact of the voice and some forms of back siderably narrower than .00025 in. and no more. The reels tend to pull tbe ground music, as yet this last speed is heretofore widely used in machines of tape in opposite directions, so that the incapable of high fidelity performance. tape is held more or less taut against Nevertheless, considering the constant the heads, as illustrated in F'ig. 2. Tbis progress that takes place in the tape is the scheme generally employed in 90· art, it is conceivable that not too many / semi-professional and professional tape years from now it will be possible to ~ . recorders to achieve close con tact be have high fidelity at 1.875 ips. At such ( tween the tape and the heads. Excessive a time the 15/16 ips might then play ~ pressure can result from excessive back GAP :.7 TAPE the role of a secondary speed where re "'= tension exerted on the tape by the sup sults of only moderate quality are re ply and takeup reels. There is usually quired. Returning to the present, it may provision for adjusting back tension. be said that nothing less than 3.75 ips Fig. 4. Meaning of azimuth alignment. Most home machines rely on pressure is compatible with a first-rate home pads to obtain firm contact between the music system, and that to be really sure good quality-are required if extended tape and the heads, because the path of good results it is still necessary to response is to be achieved at 3.75 ips. followed by the tape does not assure operate at 7.5 ips. The newer heads have gaps in the vicin such contact. If the pressure pad holder ity of .0001 in. Inserting this value into , Head Losses is improperly adjusted, head wear may the above formula, with speed at 3.75 take place at an excessive rate. Head losses are of two kinds: (1) ips, the upper response limit appears to On the other hand, it sometimes hap frequency-dependent and (2) speed-de be 18,750 cps. Tbis is the feasible re pens that a brand new head will offer pendent. Frequency-dependent losses sponse in playback. In recording there improved treble response after a mod have nothing to do with tape speed and are very serious losses that make it dif erate period of wear. What happens is are electrical in nature. Specifically, they ficult to maintain this kind of treble re that the head wears down to the point are eddy current and hysteresis losses, sponse at 3.75 ips. where the- gap is narrowest. But even which have to do with the construction It should be noted that the physical tually the gap will begin to widen with , and material of the head, and they in gap is not the same thing as the mag increased wear and high-frequency re crease with frequency. In modern heads, netic gap. The above formula takes into sponse will deteriorate. these losses are very small within the account that in a well-made head the audio range and may be left out of the magnetic gap tends to be about 10 per following discussion. cent wider than the physical gap. How o The principal head loss is due to gap ever, in a poorly constructed head, -t--.. r-..... width of the playback head and varies where the gap is not extremely straight 'f 5 inversely with tape speed. The narrower and sharply defined, the magnetic gap 5 10 the gap, the higher is the maximum fre may be considerably more than 10 per 5 quency that the head is capable of re cent in excess of the physical gap, so '\ ~ 15 producing. As a rough approximation, that the upper response limit is cor " 1\ one can use the following formula to respondingly lower than indicated 'by the ~2O Z estimate the upper response limit of a formula. As a result, it is quite possible ~ 25 \ playback .head : that a head with an advertised gap of o 5 10 15 20 25 30 35 ... 8 .'-~ ' .0001 in. may afford better treble re MISALIGNMENT-MINUTES OF ARC f=2G'y..'- sponse than another hea,d with an adver tised gap of .00009 in., or 90 micro Fig. 5. Effect of azimuth misalignment where f is the upper fre inches. appr~~~ie upon response at 7500 and 750 cps at quency limit in cps, S is tape speed in While a head may initially have a gap 7.5 ips.
30 AUDIO, • MARCH, 1960
cOlllparea with a two-track one-the Tape-to-Head Contact DEGREE OF MISALIGNMENT EXAGGERATED FOR VISUAL CLARITY proportionately smaller are the azimuth Intimate contact between the tape and losses. the heads is vital to preservation of The foregoing assumes that different high-frequency response. Failure of the heads are used for recording and play tape to hug the heads may be due to back. If the same head is employed for various factors; inadequate pressure both modes of operation, the azimuth when pressure pads are used; inade error cancels. However, when a mis quate tension when pads are not used; aligned record-playback head is used t'o accumulation of tape oxide on the heads. Fig. 6. Relative misalignment of the gaps play a commercial recorded tape, then Losses due to separation of the tape of a stereo head. treble response of course suffers. and the heads can occur in recording as Figure 5 shows how severe the losses well as playback, although they are 4. Manner in Which the Tape is due to azimuth misalignment can be. generally more severe in playback. Fig Wound and Rewound. When the tape is The curve shows the drop in response ure 7 shows the, losses at 7500 cps and wound rapidly in the forward or reverse at 7500 cps for various degrees of mis 750 cps for. various amounts of separa direction, some machines "lift" the tape alignment when a half-track head is em tion in recording at 7.5 ips. The curve slightly away from the heads. Many, ployed at 7.5 ips. It may be seen that for 7500 cps shows that separation of possibly most, home machines fail to misalignment of one half of 1 degree about 0.4 thousandths of an inch, which space the tape away from the lJ.eads redu~es output by more than 17 db can occur due to accumulation of tape during rapid wind and rewind, thereby oxide on the record head, will reduce the causing appreciable head wear, perhaps recorded level to about one-tenth of the more wear than occurs during normal level in the case of perfect tape-to-head record and playback. To avoid this un contact-a loss of 20 db. The curve for necessary head wear, it is generally pos 750 cps exhibits considerably smaller, sible to wind the tape directly from one but nevertheless substantial, losses. At reel to the other without going past the frequencies above 7500 cps, the losses heads, as illustrated in Fig. 3. It is would be much greater than indicated in merely necessary to lift the tape out of Fig. 7. its normal path past the heads-usually Figure 8 shows the separation losses a guide slot-and allow it to take the for a playback head. Here it may be shortest path between reels. The possible seen that at 7500 cps at a speed of 7.5 disadvantage of this procedure is that ips a separation of 0.1 thousandth of the tape may not be wound as smoothly an inch reduces the signal to about one as if it were following its normal path. 0.2 0.4 0.6 0.8 1.0 fourth of its potential level, a loss of 5. Care of the Heads. Head wear can TAPE-TO-HEAD SEPARATION-.OOI INCH 12 db, compared with -a loss of about 6 be minimized through suitable care, db in recording for the same amount of which includes regular cleaning of the (SOURCE: Mln ....ta Mining & Mfg. Ca.) separation. If the same head is used in heads to remove accumulated tape oxide, Fig. 7. Separation losses when recording recording and playback, and if separa and the. application of lubricants to frequencies of 7500 and 750 cps at tion is .0001 in. at both modes, then a minimize friction between the heads and 7.5 ips. loss of 18 db altogether can occur at the tape. Once the gap of the playback 7500 cps. head has widened appreciably, nothing under the stated conditions. If the fre The moral is clear. Heads must be can be done except to replace the head, quency were greater than 7500 cps, if regularly cleaned every few hours to re which is a good deal more costly than the tape speed were reduced, or if the move tape oxide. To be on the safe side, preventive maintenance. The gap does track width were inereased, the losses cleaning should take place before every not have to widen very much before the would be greater. recording or playback session. In addi head becomes unable to reproduce high In the case of stereo heads, it is im tion, at suitable intervals, the machine frequencies. To illustrate, a gap of portant to realize that it is possible for should be checked to ascertain that tape .0001 in. permits response to 18,750 cps the two gaps to be out of alignment tension is correct or that pressure pad at the 3.75 ips speed. If the gap widens with each other, as shown in Fig. 6. holders are properly adjusted. by just one ten-thousandth of an inch, Ideally, the two gaps should be in a per TO BE CONlINUED the upper response limit is reduced to fectly straight line. If they are not, as 9375 cps at 3.75 ips, which is too low sometimes happens, then it is not pos for high-fidelity purposes. sible to obtain correct azimuth alignment on both tracks. Aligning one gap auto Azimuth Alignment matically throws the other gap out of Improper azimuth alignment is one alignment. Else one has to find a com of the most COJIllllon reasons for inade promise position where both tracks are quate treble response. The gap of a cor equally affected. The best solution is to rectly aligned head forms an angle of replace the head, unless the degree of exactly 90 deg. with respect to the misalignment is so slight as not to cut length of the tape, as shown in Fig. 4. response more than two or three db at If the angle differs from 90 deg., how the upper end of the audio range. ever slightly, there are losses that in As stated before, the effect of azimuth O~~~~~~~--~--~ crease with frequency. For a given de misalignment decreases as track width o 0.2. 0.4 0.6 0.8 1.0 gree of misalignment, the loss at any is reduced. Hence four-track stereo TAPE-To-HEAD SEPARATION-.ool INCH given frequency goes up as tape speed heads have an advantage over two-track is reduced. On the other hand, the nar heads, because for a given degree of (SOURCE: Minnesota Mining & Mfg. Ca.) rower the track-for example a half misalignment between gaps the effect Fig. 8. Separation losses when reproduc track recording compared with a full upon treble response will be less with ing frequE!,ncies of 7500 and 750 cps at track one, or a four-track stereo tape four-track heads. 7.5 ips.
32 AUDIO • MARCH, 1960 -,
PAUSE STOP START 'Bi'l.]iW'4iJ.k1~I.'iJflAl , ~I.1
M':Qml#•• :.':Qml# •• 1i11:"'3~if iJ:(e[.]iJ.]lm.!.I".;lli.(.'~1 _1~1.'WI.IIM.QtM;Uij:WZ~l!Iu.!.I[·'~iiit.]!>. I INDIVIDUAL TONE CONTROLS I RECORDING VOLUME CONTROLS .11'!'1.Q'!\1;Uij:Wj~I.'iJ:tI[.]iJ.]I~teII~:W~.I~I·'[·M(·]it" '- 3 SPEEDS: 71f2· 3%· & 1 % IPS DIGITAL TAPE FOOTAGE COUNTER ' 7% IPS FREQ. RESP. 30-20,000 CPS WOW AND FLUTTER .1 % SIG TO NOISE R-55 DB 1·IIJ~I.!S.I~!$01.11!~I·.iJ:te[·]iJ·]I~[~~~~:t ..... MONITORING ON ALL TRACKS STEREO & MONAURAL INPUTS & OUTPUTS FOR TAPE DECK OPERATION I i)#M·) ••e[·]~iiit.].!ff:j1! ·'3Ifj(·Mt!l·N:·][I!.·]iI1~il;)i~·].SttDI I ,. AUTOMATIC TAPE STOPS, NO RUN-OFF 1:"'ji3iJ=i"1".'f4~[II:lit.]~[.1If.M·)(·]il -111111 n3 l:HllNNEL STEREO THE UHER STEREO RECORD III • (illustrated above and below) 4 TRACK • STEREO RECORD / STEREO PLAYBACK
THANK YOU! ~eo/t delj'=con£ained Extremely heavy demand by knowledgeable AMPLIFIERS AND SPEAKERS tape enthusiasts for the Uher Stereo Record III resulted in a temporary short supply. We IN ATTRACTIVE CARRYING CASE appreciate the patience you displayed and With 2 Dynamic Microphones are happy to advise that the Uher Stereo Record III may now be seen and heard at your nearest dealer.
WRITE Dept. A-3 for descriptive lite rature and name of nearest franchised dealer WARREN WEISS ASSOCIATES, Sole U. S. Agent, 1650 Broadway, New York
AUDIO • MARCH, 1960 33 Output Transformers
An easy-to-understand discussion of the factors that affect the performance of all output transformers. JAMES MOIR ':' IN TWO PARTS-PART II
Though it seems a drastic step, all the high-voltage circuitry can be removed. Indeed when the performance of the valve and transformer is being consid [JRLS ered, the whole of the valve circuit valve, bias resistor and its ShWlt ca pacitor, grid capacitor, and grid re sistor- can be removed and replaced by 0-7"---\- --- I Lp R Lp R~ = a single resistor having a value equal to --1 LS roOIlO rom n RLS the slope resistance ?'a of the valve under : GENERATOR its working condition. However, the valve is an active device in that it pro I (8) (e) duces signal power and thus we have to I I -= L ______..J add to our slope resistance ?'a a gener ator that we can assume to produce the (A) same power as the valve. When this is done the whole of the circuit inside the dotted box can be replaced by the two devices in (B) of Fig. 6, a resistor r a roD RL and a generator, the combination ap pearing as a power generator having no Vi= D~~' l'esistance in series with a resistance (D) (E) equal to the valve slope resistance. The output transformer itself is again Fig . 6. Practical single-ende d output circuit, (A), and its e quivalents; (B), simplest a little more troublesome. The practical form; (e ), at low frequencies; (D), between 150 and 4000 cps; (E), final equivale nt circuit is that of (A) in Fig. 4, two circuit a t freque ncies below 150 cps. separate windings coupled by the iron as the same resistance connected across will only be a small fraction of the total core with the second winding supplying the primary winding, at least at the low generator voltage for the reactance of power to the loudspeaker. A start can frequency end of the audio range. The Lp. (XL = 2ltfL ) will be small. be made by substituting a resistor R 1I LS practical circuit has now been reduced As the generator frequency is in for the voice coil to give (B) of Fig. 4, to the much simpler circuit ·of (C) in creased the reactance of Lp will increase but at the moment the next step will Fig. 6 the transformer and speaker (being directly proportional to fre have to be taken on trust for later veri voice coil being reduced to a resistor RL quency) until at some higher frequency fication. The transformer ratio, usually and an inductance L in parallel, the the reactance will be much higher than denoted by the symbol n, .has no effect 1I inductance being that of the transformer R . At, and above this frequency, the on the frequency response, so to avoid L primary winding measured at some low inductance L1I can be removed for it has having to multiply every impedance by audio frequency with the secondary no effect on circuit performance and the n 2 it is simpler to assume that the turns winding open circuited. circuit then consists of the generator ratio is 1 : 1, the two windings having If the generator is assumed to produce and two resistors, and R . At these fre equal numbers of turns. L constant volts at all audio frequencies, quencies the equivalent circuit ?'a will be As was seen earlier in this discussion, the variation of voltage across RL and that of (D) in Fig. 6, the output voltage a load resistor of, say, 1000 ohms con L1I will follow exactly the same law as will clearly be nected across the secondary of a 1 : 1 the variation with frequency of the volt transformer has exactly the same effect RL age across the loudspeaker voice coil in Vo= V,x--- · j'a+ R L * Technical Directm', Goodmans Indus· the practical circuit. This is the simpli tries, Ltd., Wembley, Middx., England. fication that is desired. and will be constant at this value at all Even without putting values on RL it higher frequencies (though see the later if; easy to see the sort of frequency re comment about high-frequency re sponse that will be obtained at low fre sponse) . The requirements for a flat re quencies and to get an idea of the design sponse are now fairly clear; the induc steps that are necessary to get a flat re tance of L1I should be sufficiently high (A) (8) sponse. With the generator (an a.f. oscil to ensure that it does not shunt current lator) set to a near-zero frequency, cur away from RL for when the current in Fig . 4 . When the ratio of primary to rent will flow around the circuit and the RL falls the voltage across RL falls and secondary turns equals n, the trans generator voltage will be dissipated the frequency response begins to de former and resistance of (A) can be re- across ?'a in series with RL and Lp in teriorate. placed by (B), where Rl = nZRz' parallel. The voltage across R r, and Lp The more technically minded will see
34 AUDIO • MARCH , 1960 Ie
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AUDIO • MARCH, 1960 35 than the required anode-to-anode load (8) (A) 3400 ohms. If it is decided to allow a I I loss of 3 db at 50 cps the reactance of I I the primary inductance Lv must also be 0 V I I -...." 3000 ohms at this frequency and Lv is >_1>° I V I ...... then 3000 (2Jt x 50) = lOR approxi 4 mately. If the 3-db point must be at 10 .3'" / I I 0 6 cps, then the inductance must be five N I I\. r.- XL times higher or 50 henries. 1/ ~ " J"i 3 10 0 f---l Vi R Vo I ·t 1\ ~ j Practical Design 12 I------; 0 If ':II 1\ -' 14 3 While dealing with a specific example I I it is worth calculating the number of I I turns and the size of transformer re , I quired to obtain the primary inductance I I suggested. Any required value of in 0.2 0.5 1.0 2 .25 0.5 1.0 2 ductance can be obtained in either of XL f j XL fj two ways; a small number of turns on Torf; Tor~ a large iron core, or a large number of Low-frequency lou du e to primary inductance High-frequency loss due to. leakage inductance turns on a small iron core. A large core and few turns should result in small sig Fig. 7. Basic output transformer characteristics. fo is the frequency at which the nal power losses and a high price, with reactance XL is equal to the resistance R, and fl is the frequency at which the loss the converse being true if a small core is to be determined. and a large number of turns are adopted. a flaw in this reasoning. At those low quency by increasing the value of Lp. The choice of core size is thus somewhat frequencies where the reactance of Lp For reasons that will emerge later, it arbitrary unless the permissible power is low compared to R L } the total circuit is usual to take as the cutoff frequency, loss can be specified. An examination of impedance will fall and the current that frequency at which the reactance of the lists of some of the leading manu drawn from the constant-voltage gen Lp equals the resistance RIl' this being facturers shows that their high-quality erator will rise and thus tend to main the frequency at which the output is transformers have an over-all volume of tain constant the voltage across RL and down by 3 db. This is an arithmetical about two cubic inches per watt, sug Lp. A detailed analysis shows that this simplification rather than the point in gesting that a llh-in. stack of the lami compensating effect can be exactly al the frequency range at which there is nations shown in Fig. 8 will handle 20 lowed for by assuming that the gener a significant cutoff, for the power output watts, though this is a point that will be ator resistance has a value lower than i" only falling away at the rate of 6 db checked more closely at a later stage the slope resistance r a and in fact is per octave. when the distortion products are being equal to the valve slope resistance r a The shape of the frequency response, studied. and the load resistance RL in parallel. i.e. the relation between the ratio Va/Vi The inductance of a coil wound on a The equivalent circuit then reduces to and frequency, is controlled by the ratio closed iron core such as Fig. 3 is given that of (E) in Fig. 6 and has the same Df XL to Rg and thus is unalterable. All (but only approximately) by voltage/frequency relation for Va/Vi as output transformers have the same shape L= 3.2 T~JA..A (3) the appreciably more complex circuit of frequency response but a good trans 108 x l of (A) in Fig. 6, an effective demon former is up to its level value at a very where T = nU!l1ber of turns. stration of the advantages of equivalent low frequency whereas a poor trans .A = cross sectional area of core. circuits. former does not achieve its "flat" value I' permeability of core. In a simple circuit such as that of (E) = until a much higher frequency is l = length of flux path. in Fig. 6, it is fairly easy to see that Va reached. It is convenient to display this (all dimensions in inches) will tend to approach Vi as the reactance universal response in the form of a of Lp becomes large relative to the re single curve Fig. 7, fa being the fre All the f actors that appear in this sistor R g• The reactance XL = 2rr.fLp is quency at which the reactance XL of Lv formula are unambiguous except JA., the permeability of the core material, and directly proportional to frequency and equals the resistance R g • From this it thus it is clearly gDing to be difficult to will be seen that at this cutoff frequency this is difficult to specify because the maintain XL large compared to Rg} where FJFa=l, the loss is 3 db, but at permeability of any of the usual core down to such very low frequencies as a half this frequency the loss is only 7 db. materials is a function of the core flux few cycles per second. When transform Some of the simpler relations are given ers are used there is no alternative to ac in Table I. cepting a frequency response that falls Some realism is put into the picture I away at low frequency, but the fre by taking a look at the sort of values of I quency at which the falloff commences primary inductance Lv that are required 9 x 103 can be moved down to any desired fre- in practice if a flat frequency response 8 is to be obtained. The two EL34's used "" 7 in the earlier example require an anode ~.... 6 ::; 5 V ;;; ./ to-anode load of 3400 ohms and have a <1: 4 quoted slope resistance r a of 15,000 3 ohms, though as a push-pull stage is ...~ .J' 2 V being considered the effective source re 11 ...... sistance can be taken as 30,000 ohms. 0 1000 10,000 This is some ten times the required FLUX DE NS ITY-GAUS S anode-to-anode load, a relation typical of tetrodes and pentodes and it results Fig. 9. Typical relation between core flux in the effective generator resistance Rg density and permeability for transformer Fig. 8. Typical lamination shape. being 3000 ohms, only slightly lowcr steel.
36 AUDIO • MARCH, 1960 It is an axiom ill high fidelity that no single speaker is capable of ideally reproducing the entire musical range of a symphony orchestra. At least two speakers, each specifically designed to re produce a part of the sound spectrum, are needed to do a really adequate job. ElECTRO-VOICE UlTRA-COMPACT SYSTEMS OFFE'R MORE THAN JUST BASS RESPONSE Ultra-compact systems are no exception to this rule. This is why two year's research went into the development of Electro-Voice's new ultra-compact line. In its tradition of providing the finest, Electro-Voice would not introduce a system in which only the bass speaker and enclosure had been engineered to the special requirements of the compact system. Each component within that enclosure had to be designed to make certain it was a perfect match to the other elements in the system. Laboratory measurements and exhaustive listening tests had to be coordinated and differences resolved. The result of these efforts can now be heard from the new Ley ton, Esquire 200, Regal 300, or Royal 400. These speaker systems produce bass of astounding definition and solidity, clear undistorted treble, and remarkable brilliance in their upper ranges. One of the key factors in producing this purity of sound was the judicious choice of crossover points, restricting each of the specially designed speakers to cover only the range over which its performance is most perfect. In all models, for example, the crossover from woofer to mid-range occurs at 200 cycles per second. With this degree of specialization, all forms of distortion are held to the lowest levels possible. Operating below 200 cycles, the bass speaker is not required to reproduce any of the mid-range spectrum and can act as a true piston. The specially designed mid-range speaker can then be made to provide exceptionally flat response, with its level matched perfectly to that of the woofer. The very-high-frequency com pression driver faces only the necessity of adding "sparkle", and dispersing high-frequency sound throughout the room. The result is a clarity and definition of sound that can best be described as transparent - enabling you to feel the deepest bass, marvel at the effortless clarity in the mid-range, and de light in the brilliant definition of the upper harmonics. Whether you intend to purchase a new high-fidelity speaker system now or later, Cutaway we urge you to visit your Electro-Voice dealer view of Esquire 200 for a demonstration of these remarkable instru Speaker System ments. You may also write directly to the factory for a Mahogany, Limed Oak, orWalnut..$123.oo complete description of these new units. Ask for High-Fidelity Unfinished Birch • . ••• ...••. • • •• .. $111.00 Catalog No. 137.
DEPARTMENT 3 0A, BUCHANAN, MICHIGAN
AUDIO • MARCH, 1960 37 wound on to the core as a single coil formance. A flat frequency response is having the secondary turns wound on maintained up to frequencies of a few LE AKAGE FLUX PATH top as in F 'ig. 10, though this is not the thousand cps but it then begins to fall usual practice when a transformer hav away again, an effect that is not pre
USEFUL FLUX PATH ing a high-quality performance is re dicted by the equivalent circuits as they quired. Why is this simple (and there stand in Fig. 6. The missing element is fore low priced) construction not an inductance that represents the effect adopted ~ The answer is that the relative of the magnetic flux which strays from disposition of the two windings on the the iron path and thus fails to link both Fig. 10. Secondary wound over primary. core controls the high-frequency per coils. It is omitted from Fig. 6 because Suitable only for transformers d e al ing formance, an aspect of the design prob it has no effect on tbe performance of w ith a restricted freque ncy rang e. lem that can now be considered. the transformer at low frequencies. It is best approached by returning to The clearest mental picture is obtained density. Typical variations in permea the first section of this discussion deal by assuming that the whole of the flu.\: bility with flux density taken from the ing with the choice of tmns ratio. It produced by the primary winding by data sheets in a manufacturer's lists, are was then stated that all the magnetic passes a few of the secondary tmns, illustrated by Fig. 9, but experience flux produced by the primary winding leaving these few turns as an inductance shows that these permeability values was confined to the core and thus inter outside the transformer and in series are not achieved under working condi linked both coils. When the turns ratio with the secondary load resistance R L . tions. Data for these curves are invari and number of turns are being consid It is really immaterial whether we con ably taken on ring samples without air ered, this assumption is perfectly valid sider that 99 pel' cent of the flux links gaps and after annealing. Laminations but when the high frequency perform with 100 per cent of the secondary huns punched from the same material are ance is under examination the assump 01' that 100 per cent of the primary flux rarely annealed after punching, are then tion is too sweeping. In the simple ex links with 99 per cent of the secondary assembled with air gaps that are small ample of Fig. 11 magnetic flux lines turns, for it is the product of (flux) x but lmavoidable and finally used in emerging from the top of the coil have (tmns) that is important; but a clearer transformers that carry small unbal two alternative paths that can be fol- picture of the process is given by the anced anode currents, all important fac second approach. The inductance that tors in reducing the permeability below exists as a result of the failure of the the ring-sample value. It is more real USEFUL FLUX primary flux to link all the secondary istic to use permeability values that are turns is generally known as the leakage half those read from Fig. 9 when calcu inductance and can be measured on any liLting the winding inductance from Eq. of the standard a.c. bridges by short (3) . The permeability will be seen to circuiting the secondary terminals and vary by a factor of about five times over measuring the inductance that appears a range of flux densities between 200 at the primary terminals. The same final and 5000 gauss. answer is obtained if the primary termi The inductance of the primary wind LEAKAGE FL UX nals are shorted and measurements made ing will also vary with flux density by at. the secondary terminals but the two Fig . 1 1. Paths of w orking and le a kage the same factor of five times, so that the measmements will differ in the ratio of frequency response will change with flu xes in basic transformers the (turns ratio) 2. power output unless the inductance lowed back to the bottom of the coil. The general effect of this leakage in measmed at some low flux density is The designed path is that through the ductance on the frequency response is adequate to maintain a flat response. iron core, the path that is followed by now fairly easily seen from a considera The choice of an appropriate flux den the great majority of the magnetic flux. tion of its position in the equivalent cir sity and the related value of permea However, a very small proportion of the cuit where it appears in series with the bility is somewhat arbitrary but if a total flux leaks out of the iron and fol secondary load resistance RL as in F 'ig. value for ,J.L of 1500 corresponding to a lows paths through the air as indicated, 12. As the signal frequency rises, the core density of 500 gauss is used, the with the result that all the flux from the reactance of LBO rises proportional to final performance is likely to be very primary winding does not link with all frequency, eventually becoming com acceptable. However, this problem of the turns from the secondary winding. parable in value to the secondary load core density will come up again at a In a good transformer as much as 99.9 resistor RL and with further increase in later stage when harmonic distortion is per cent of the flux from the primary frequency the reactance of LBO will ex being considered. winding links with the secondary but the ceed R . The signal voltage produced Using the two cubic inches per watt remaining 0.1 per cent is responsible for L by the genemtor is now divided between figme it might be expected that a 11/2-in. the majority of the high frequency three circuit elementS- ?'a the equivalent deep stack of the laminations shown in losses. A return to the equivalent cir resistance of the generator, LBO the leak Fig. 8 would handle 20 watts with ease. cuit of (C) in Fig. 6 will ease the ex age inductance, and RL the secondary The core area of a 11/2-in. stack is planation. load resistance- and therefore V 0 will roughly 11/2 sq. ins. and the iron path The primary inductance Lp appears fall off with increase in frequency at length 8 inches. Inserting these values in parallel with the load resistance Rr. the rate of 6 db per octave. into Eq. (3) shows that about 1100 turns but above a quite low frequency (50 to are required to give an inductance of 10 150 cps) the reactance of this inductance henries while 2400 turns are necessary becomes so high in comparison to the to obtain 50 henries. When harmonic resistance RL that the current shunted distortion is considered at a later stage, off the load resistance becomes quite it. will be shown that in general the pri negligible. Above this frequency, Lp has mary inductance required to hold har no effect on the frequency response 'monic distortion to an acceptably low which is then determined by the resist limit automatically ensmes a good fre ances ?'a and R£ and is thus independent quency response. of frequency, the conclusion arrived at Fig. 12. Equivalent circuit a t fre quencies The specified number of turns can be when discussing the low-frequency per- above 4000 cps.
38 AUDIO • MARCH , 1960 Ease of control: Bass and treble control are convenient dual General Electric 56 -watt stereo concentric type to permit adjustment of channels together or separately for matching or different speaker systems. Contour control provides automatic bass boost at low volume. Balance amplifier-Superior in the four control is continuously variable to "off" on either channel. Value: In General Electric stereo amplifiers you get all the most vital areas wanted features-without expensive extras which boost the price but add little to performance or enjoyment. The result is When you select an amplifier fo r your stereo system, you should honest-to-goodness quality at sensib le prices. pay particular attention to its power, versatility, ease of control and functional value. These are the four areas which will chiefly The G-7700 comes complete in a beige vinyl case; the G-7710 determine the pleasure and satisfaction you derive from your in a white vinyl case. The price is a modest $189.95*, including amplifier, and these are the four areas in which the General case. (The G-7600 delivers 40 watts, 20 watts per channel, Electric G-7700 is most outstanding. $139.95*.) Other General Electric stereo amplifiers at $119.95* and $169.95* including case. Power: 56 watts (28 watts per channel) music power - more than enough to drive even low-efficiency speakers . Response is FM-AM Tuner, Series FA-l0. Receives ev en weak signal s with unu sually low distortion, hum and flat (± 0.5 db) from 20 to 20,000 cycles, with less than 1% dis noi se level. Drift·free . Vi sual met er for pinpoint tortion . Channel separation 40 db for maximum stereo effect. FM ce nter chann el tuning and optimum AM signal tuning. RF amplifier sta ge in both FM and AM in cre as es sensitivity, FM multipl ex ia ck for stereo Versatility: Two simple multi-purpose controls let you select a adaptor. Built·in AM antenn a; FM dipole in cluded . variety of inputs-stereo and monophonic cartridges (both mag Cases to match all G·E amplifi ers. $129.95 *. netic and ceramic), tape heads, tape machines and tuners . The General Electric Company, operating mode control gives you flexible selection of different Audio Products Section, Auburn, N. Y. *Manufacturer's suggested resa le prices. combinations of stereo or monophonic operation. Slightly higher in the West.
GENERAL _ ELECTRIC
AUDIO • MARCH, 1960 39 problem as it may be shown that if the increased. In general any resistance in impedance of the source is very small, a the cll'cuit prevents the inductance dra,,' FLUX B+ sinusoidal voltage applied to the trans ing the harmonic currents it requll'es to DEN SIT Y former primary will result in a non maintain a sinusoidal flux waveform. If sinusoidal primary current, a sinusoidal 8, sinusoidal flux waveform is not main flux waveform, and a sinusoidal second tained then the waveform of the second ary voltag-e. The significant point is ary voltage will be non-sinusoidal. contained in the phrase "if the resistance When considering the low-frequency of the source is very small" and the response of a transformer it was sho"-11 H- H+ MAGNETIZI NG question that immediately jumps to that the resistance that controls the re FORCE mind is, how small ~ There are few sponse is the parallel combination of the abrupt discontinuities in nature and it source and load resistances. The same if; unlikely that the distortion will prove parallel combination also controls the to be zero when the source resistance is harmonic distortion that is generated. zero and yet rise sharply for very low If the transformer is a poor example values of source resistance. Common with high resistance windings these wind Fig. 16. Typical B/ H relation for iron sense is right on this point. A detailed ing resistances must be added to the load laminations. analysis shows that the percentage dis resistor before working- out the parallel tortion is related to the ratio of circuit combination. ing- coil. Neither of these requiremen ts resistance to the inductive reactance of Most of the manufacturers of trans is met in a magnetic circuit that COll the primary winding of the transformer former steels have produced CUl'ves show sists wholly of magnetic material. What and is a function of the maximum flux ing the relationship between distortion does happen is illustrated by Fig. 16, a density at which the iron is worked. and the ratio of the effective circuit re typical B/H relation for a transformer This latter result is to be expected for sistance to the reactance of the primary steel. there is a fair degree of proportionality winding. Typical CUl'ves fOl' a 4 pel' Starting from zero current in the between H and the resultant B if the cent silicon steel commonly used in high magnetizing winding, but with the iron flux density is not allowed to exceed quality transformers are shown in Fig. path magnetized by the previous cycles point a in Fig. 16. Unfortunately a low 17. The most significant information to of the supply, the flux density in the flux density means a larg-e core and an be obtained from the curves is the very iron rises roughly proportionately to the expensive transformer. high distortions that occur even at low current up to point a in Fig. 16 then The advantages of a low-resistance flux densities when the source resistance less than proportionately from a to b, source ill minimizing- harmonic distor is comparable with the reactance of the and finally saturates at c; very large tion are less obvious and need a more transformer primary winding. Earlier in increases in magnetizing- current are detailed explanation. If a generator of the contribution it was shown that a then required to produce very small zero resistance and a sinusoidal voltage transformer having a primary induct increases in fllL,\,: . If the direction of the waveform supplies current to a resistive ance of only 10 henries would have a current flow is reversed, B commences to load, both the current and voltage have frequency r esponse only 3 db down at fall, not along the path c, b, a, but along sinusoidal waveforms. When the resist 50 cps when used with two EL34 valves a new path, d, e, f) where the values of ance load is replaced by an inductance B are alway!> hig-her than were obtained working into a load of 3400 ohms, It is the voltag-e waveform remains sinusoidal interesting to calculate the harmonic dis for the same values of H when H was but the current waveform is distorted by increasing. The magnetizing current tortion that is produced if such a trallS just the rig-ht amount to produce a sinu fOl:mer is used. must be l'eve1'sed to reduce B to zero at soidal flux waveform and thus a sinu At a frequency of 50 cps an induct f, a symmetrical path g, h, i, Ie, l then soidal secondary voltage waveform. The ance of 10 henries has a reactance of being traced as H increases to a negative primary CUl'rent wave is then found to maximum, reverses, and retUl'ns to zero. contain a high percentage of third, fifth, 3140 ohms, approximately equal to the The point of importance is that the path and seventh harmonics. In an inter effective generator resistance when using followed by the value of B encloses an mediate condition when the cll.'cuit con two EL34's in push-pull. The left hand area instead of merely following a tains some resistance, the cUlTent drawn curve for roL = R is then appropriate. straight line. From the B / H relation of from the source is less distorted but the The core flux density when the power Fig. 16 it may be deduced that a sinu distortion of the voltage waveform is (Gontim£ed on page 68) soidal magnetizing current in -the pri.- - mary coil will not produce a sinusoidal flux waveform in the iron circuit. As the secondary voltage is proportional to the rate of change of flux, a sinusoidal sec 1 2 ~--4-~~----+----+---7f----r--~ ondary voltage can only be produced by a sinusoidal flux waveform and this will in turn only be produced by a non 10 ~--1f---+----+-~~----r----t sinusoidal current wave in the primary Fig . 17. Third-har ;/1. winding. monic distortion in ~8 f--I--+----Ic-;C---+----+---:;;;;o!""----+-- o At this stage it would appear that an the voltage across ;:: impasse has been reached for distortion l as a function of g6 ~1--+'1-~----::;;~::::""--+----b"""'9----I less reproduction demands that a sinu the flux density B Ci soidal voltage on the grid of the output for values of roL/ R, valve produces a sinusoidal voltage across the output transformer secondary, o though it has been shown that this result can only be achieved by supplying a non-sinusoidal current to the transformer primary. However, the impasse is only 4 6 10 the result of shallow thinking- about the FLUX DENS IT Y B- KILOGAUSS
42 AUDIO • MARCH , 1960 Ease of control: Bass and treble control are convenient dual General Electric 56 -watt stereo concentric type to permit adjustment of channels together or separately for matching or different speaker systems. Contour control provides automatic bass boost at low volume. Balance amplifier-Superior in the four control is continuously variable to "off" on either channel. Value: In General Electric stereo amplifiers you get all the most vital areas wanted features-without expensive extras which boost the price but add little to performance or enjoyment. The resu It is When you select an amplifier for your stereo system, you should honest-to-goodness quality at sensible prices. pay particular attention to its power, versatility, ease of control and functional value. These are the four areas which will chiefly The G-7700 comes complete in a beige vinyl case; the G-7710 determine the pleasure and satisfaction you derive from your in a white vinyl case. The price is a modest $189.95*, including amplifier, and these are the four areas in which the General case. (The G-7600 delivers 40 watts, 20 watts per channel, Electric G-7700 is most outstanding. $139.95*.) Other General Electric stereo amplifiers at $119.95* and $169.95* including case. Power: 56 watts (28 watts per channel) music power - more than enou gh to drive even low-efficiency speakers. Response is FM-AM Tuner, Series FA-l0. Receives even weak signals with unu sually low di stortion, hum and flat (± 0.5 db) from 20 to 20,000 cycles, with less than 1% dis noi se leve l. Drift-free . Vi sual met er for pinpo int tortion. Channel separation 40 db for maximum stereo effect. FM center channel tuning and optimum AM signal tuning. RF amplifier stage in both FM and AM in cre ases sensitivity, FM multiplex jack for st ereo Versatility: Two simple multi-purpose controls let you select a adaptor. Built-in AM antenna ; FM dipol e in clud ed. variety of inputs-stereo and monophonic cartridges (both mag Cases to match all G-E amplifiers. $129.95 *. netic and ceramic), tape heads, tape machines and tuners . The General Electric Company, operating mode control gives you fle xible selection of different Audio Products Section, Auburn, N. Y. *Manufacturer's suggested reso le pri ces. combinations of stereo or monophonic operation. Sl igh tl y higher in the West.
GEN ERAL e ELECT RIC
AUDIO • MARCH, 1960 39 ular arrangement of coils can be calcu lated with a moderate degree of accuracy and it is worthwhile examining the rela tionship for the light it throws on the factors responsible for leakage. A simple SPEAKER formula that gives good agreement with measured values is
(A) 2Jt1· Lso = 3 . 2 X T! x - l- ONE PRIMARY AND TWO Al----~ __~P~4~~ SECONDARY SECTIONS (8) THREE PRIMARY AND TWO 8 SECONDARY SECTIONS ( S + i + i ) X 10- H. Fig . 13. Further subdivision of windings to reduce leakage reactance. the symbols having the meaning shown The point in the frequency range at of sub-division may be carried still fur in Fig. 14. From this it will be seen that which the falloff begins to be significant ther, both primary and secondary wind the leakage inductance is increased by (rather arbitrarily, the frequency at ings being sub-divided into sections and an increase in the radius r of the wind which the response is 3 db down) is a interleaved. Some typical arrangements ing, by an increase in S, the spacing be function of the ratio of the reactance of are shown in Fig. 13. That of (B) has tween coils or decreased by an increase Lso to the combined total circuit resist particular advantage in push-pull cir in l, the wound length of the coil. A lamination having a long narrow window ance 1·a + R L • When Xso = 2JtfLso = 1·a + cuits in that the two half primaries can RL the loss is 3 db and increases at the be made to have the same resistance by such as that of (A) in Fig. 15 will give rate of 6 db per octave as shown at (B) using P / 4 and P / 4 in series for one a lower leakage inductance per turn in Fig. 7. The similarity between the half primary, with P / 2 for the other than one with a square window such as relations governing the high-frequency half. This also equalizes the leakage that at (B) . This is not quite the ad loss and those governing the low-fre inductance from either half primary vantage that it appears at first sight, for quency loss will be apparent on com into the secondary. laminations with long windows tend to paring (A) and (B) in Fig. 7. There are two alternative approaches have long iron p'aths and thus have a to the problem of reducing leakage in lower primary inductance Lp per turn Leakage Reactance ductance that are worthy of comment. than one with a square window. Never theless there is an advantage to be gained Clearly if the response is to be well Reduction of the spacing between the primary and secondary sections is clearly by an appropriate choice of lamination maintained up to the highest frequencies, shape. Lso must be reduced to a minimum so the factors that affect Lso will now be considered. Little thought will be re Distortion quired to decide that the leakage induct The last performance characteristic to ance will increase as the number of turns be discussed is the generation of har on the windings increase, following the monics and intermodulation distortion normal law that inductance is propor r=MEAN by an iron-core device. This is not such tional to (turns) 2. Advantage cannot be RADI US a well understood subject and in conse taken of this relation to reduce the leak quence will be covered in rather greater age inductance, for as we have seen detail than was thought necessary for earlier the total turns are fixed by the some of the earlier characteristics. response that is desired at the low-fre Fi g . 14. Dime nsi ons required for calcula- How does distortion arise in an iron quency end of the range. The alternative tion of lea kage inductance. cored device'! Fundamentally it is due course of action is to reduce the amount an advantage but a limit to this tech to the non-linear relation between the of leakage flux from the primary that nique is set by the necessity of providing magnetizing force H and the resultant fails to couple with the secondary wind interwinding insulation between the sec flux density B produced in the iron core, ing. This is a question of bringing the tions capable of withstanding the plate but it is also due to the presence of secondary winding as close to the pri supply voltage and signal voltage excur hysteresis in magnetic materials. mary winding as is physically possible. sions. It is usual to operate amplifiers In an ideal magnetic material, the Some possibilities will be considered. with the secondary winding at or very magnetizing force H would produce a The worst possible arrangement is near ground potential but with the pri magnetic flux density B proportional to that of the elementary transformer of mary winding at B + potential. The H. Thus if H were doubled (by doubling Fig. 11 where the primary winding is newer insulations with high dielectric the current or the number of turns) B arranged on one limb and the secondary strengths that are now appearing offer should double. Moreover, B should have winding on the other limb. Leakage flux considerable advantages in reducing the the same value for any particular value then follows the path shown and may thickness of the intersection insulation. of H, irrespective of the du:ection in amount to an appreciable fraction of the The leakage inductance of any partic- which the current flows in the magnetiz- total flux. It may be greatly reduced by winding the secondary on top of the primary winding as shown in Fig. 10 and abandoning the core type of lamina tion shown in Fig. 11 in favour of the shell type of Fig. 8. Magnetic leakage then follows the path shown in Fig. 10 and will obviously be a great deal less than in the simple arrangement of Fig. 11. Further reduction in leakage may bE achieved by dividing either winding (A) (8) into two halves and disposing them Fig . 15. laminations having long windows (A) have lower leakage inductance than about the other winding. This technique those having square windows a s a t (B).
40 AUDIO • MARCH , 1960 U S PATENT 2 775 309 There are hundreds of Uriited States • • "Patents on loudspeakers. Most of them relate to minor improvements; a few have changed the face of the speaker industry. AR's patent on the acoustic suspension speaker system has had far-reaching effects. A very large number of speakers has been produced under the patent by AR and its licensees, and speaker design in general has been given a new direction. In our opinion this patent has proved to be the most significant issued in the speaker field since 1932, when Thuras was awarded a patent on the bass-reflex enclosure. The basic idea of the acoustic suspension system is that the speaker works against an elastic pillow of air sealed into the cabinet instead of against mechanical springs of its own. This design makes possible vastly improved bass · reproduction (particularly from the point of view of lowered distortion), and . simultaneously dictates small cabinet size. The acoustic suspension principle is now used in four AR models-the AR-1, AR-2, AR-2a, and AR-3, priced from $89 to $225. We invite you to listen to these speakers at your dealer's, or, if you live near New York City, at the AR Music Room in Grand Central Terminal. Literature on AR speakers is available for the asking. ACOUSTIC RESEARCH, INC. 24 Thorndike Street Cambridge 41, Massachusetts problem as it may be shown that if the increased. In general any resistance in impedance of the source is very small, a the circuit prevents the inductance draw sinusoidal voltage applied to the trans ing the harmonic currents it requires .to former primary will result in a non maintain a sinusoidal flux waveform. If sinusoidal primary current, a sinusoidal a sinusoidal flux waveform is not main flux waveform, and a sinusoidal second tained then the waveform of the second ary voltage. The significant point is ary voltage will be non-sinusoidal. contained in the phrase "if the resistance When considering the low-frequency of the source is very small" and the response of a transformer it was shown H- H+ MAGNETIZING question that immediately jumps to that the resistance that controls the re FORCE mind is, how small? There are few sponse is the parallel combination of the abrupt discontinuities in nature and it source and load resistances. The same :is unlikely that the distortion will prove parallel combination also controls the
h to be zero when the source resistance is harmonic distortion that is generated. zero and yet rise sharply for very low If the transformer is a poor example values of source resistance. Common with high resistance windings these wind Fig. 16. Typical B/H relation for iron sense is right on this point. A detailed ing resistances must be added to the load laminations. analysis shows that the percentage dis resistor before working out the parallel tortion is related to the ratio of circuit combination. ing coil. Neither of these requirements resistance to the inductive reactance of Most of the manufacturers of trans is met in a magnetic circuit that COll the primary winding of the transformer former steels have produced curves show sists wholly of magnetic material. What and is a function of the maximum flux ing the relationship between distortion does happen is illustrated by Fig. 16, a density at which the iron is worked. and the ratio of the effective circuit re typical BIH relation for a transformer This latter result is to be expected fol' sistance to the reactance of the primary steel. there is a fair degree of proportionality winding. Typical curves for a 4 per Starting from zero current in the between H and the resultant B if the cent silicon steel commonly used in high magnetizing winding, but with the iron flux density is not allowed to exceed quality transformers are shown in Fig. path magnetized by the previous cycles point a in Fig. 16. Unfortunately a low 17. The most significant information to of the supply, the flux density in the flux density means a large core and an be obtained from the curves is the very iron rises roughly proportionately to the expensive transformer. high distortions that occur even at low current up to point a in Fig. 16 then The advantages of a low-resistance flUx densities when the source resistance less than proportionately from a to b, source in minimizing harmonic distor is comparable with the reactance of the and finally saturates at Cj very large tion are less obvious and need a more transformer primary winding. Earlier in increases in magnetizing current are detailed explanation. If a generator of the contribution it was shown that a then required to produce very small zero resistance and a sinusoidal voltage transformer having a primary induct increases in flux. If the direction of the waveform supplies current to a resistive ance of only 10 henries would have a current flow is reversed, B commences to load, both the current and voltage have frequency response only 3 db down at fall, not along the path c, b, a, but along sinusoidal waveforms. When the resist 50 cps when used with two EL34 valves a new path, d, e, f, where the values of ance load is replaced by an inductance working into a load of 3400 ohms. It is Bare alwaY!!i higher than were obtained the voltage waveform remains sinusoidal for the same values of H when H was interesting to calculate the harmonic dis but the current waveform is distorted by tortion that is produced if such a trans increasing. The magnetizing current just the right amount to produce a sinu must be reversed to reduce B to zero at fo-.:mer is used. soidal flux waveform and thus a sinu At a frequency of 50 cps an induct f, a symmetrical path g, h, i, lc, l then soidal secondary voltage waveform. The ance of 10 henries has a reactance of being traced as H increases to a negative primary current wave is then found to maximum, reverses, and returns to zero. contain a high percentage of third, fifth, 3140 ohms, approximately equal to the The point of importance is that the path and seventh harmonics. In an inter effective generator resistance when using followed by the value of B encloses an mediate condition when the circuit con two EL34's in push-pull. The left hand area instead of merely following a tains some resistance, the current drawn curve for ooL = R is then appropriate. straight line. From the BIH relation of from the source is less distorted but the The core flux density when the power Fig. 16 it may be deduced that a sinu distortion of the voltage waveform is (Continued on page 68) soidal magnetizing. current . in .the. pri- . mary coil will not produce a sinusoidal flux waveform in the iron circuit. As the secondary voltage is proportional to the rate of change of flux, a sinusoidal sec ondary voltage can only be produced by a sinusoidal flux waveform and this will in turn only be produced by a non 10~--~--~--~~~+----r----+ sinusoidal current wave in the primary Fig. 17. Third-har <11 winding. monic distortion in ~ 8 1---I-+----b,L..-l----+---:"""""'---l----i At this stage it would appear that an the voltage across o ~ impasse has been reached for distortion L as a function of ~ 6 ~L.J.....I~-I---~£..--+----+::..,...II!!::F----l less reproduction demands that a sinu the flux density B '"is soidal voltage on the grid of the output for values of OlL/R. [] valve produces a sinusoidal voltage across the output transformer secondary, though it has been shown that this result can only be achieved by supplying a non-sinusoidal current to the transformer primary. However, . the impasse is only 2 4 6 8 10 the result of shallow thinking about the FLUX DENSITY B-KILOGAUSS
42 AUDIO • MARCH, 1960 another P?'esto pTecision ?'ecording tool to ?nake YOUT job easieT.
The new Presto 850 is the only professional tape at sig nificantly lower operating costs. Separate recor.deL that converts in seconds from %" to switches provide correct tension even when r eel \~" tape, and vice versa-and it's from Presto, sizes a r e mixed. Pop-up playback head shield for makers of more professional so und-recording right-hand head disappears in STOP and FAST, equipment than any other manufacturer in t he completely exposing' all heads for easy sweep world. The new, flexible 850 ends the need to loading and fast, sure editing. Safe tape ha n keep expensive equipment sitting around idle. dling at top speed is assured. Interlocks prevent Conversion from lAl" to %" tape head assemblies acciden tal u se of RECORD circuit . r equires only. a screwdriver and a few seconds. r------, Based on the successful 800, the use-proved 850 T O' get cO'mp let e specifi catiO'n s O'n the new 850, provides sllch exclusive f eatures as: an edit which is available in cO' nsole, porta ble a nd rack switch for one-hand runoff during editing and mounting mO'dels, ma il this cO'upO'n to'day. a ssembly of master tapes, eliminating messy @ BOGEN -PRESTO, Dept. A-3, Paramus, N. J. tape overflow · a molded epoxy-resin drum br ake A Divi.• ion of The Siegle,' COT po ,·nti on. system with double shoes to end brake-main ~arn e ______tenance headaches • four-position plug-in head assemblies instantly interchangeable without Address______realignment • three-track st ereo master control City Zone_ State _____ (optional) for special reco rding effect s · three Presto A908 amplifiers stacked on an easy-to wO.rk-at console, in portable cases'or for rack. PR. S TO The 850 delivers a high production editing rate ~------~ ------~ AU DIO • MARC H, 1960 43 AUDIO ETC (fl·011t page 14) levels are carefully checked and the table gram. This calibrated adjustmellt--start sidewise Qn the recQrd does lIQ harm but built intQ Qne permanent SPQt, immQvably. ing with the cartridge flQating at zerQ merely generates a perfectly hideQus squawk. I will admit at Qnce that my turntables fQrce-is claimed tQ be mQre accurate than Bad fQr the nerves, anyhQw, even SQ. are Qnly SPQradically level. FQr Qne thing, any cQmmercially available gram scale; The minQr trQubles Qnce cQrrected, the they aren't built-in. They sit, in bQxes I'm nQt inclined tQ argue thQugh I dQn't arm behaved beautifully and, indeed, has placed Qn tables Qr side shelves; Qr they gQ in fQr micrQ-accurate stylus-fQrce arQused in me a desire tQ CQnvert my en stand Qn attached legs. I have yet tQ finu tests. The scale is clear, unhampered, PQsi tire semi-permanent set-up tQ the Empire a shelf Qr table that is autQmatically flat tive and very simple, and the range Qf ad 98, a prQject that is technQlQgically tQQ -Qr even flat all Qver; mQst are varyingly justment is widely spread Qut. If I am drastic at the mQment. The arm nQt Qnly rQunded Qver their minutely irregular sur right, the spring is such that the dQwn plays uphill and dQwn and at any plane Qf faces. The legs Qn my flQQr-standing tables ward fQrce is virtually linear Qver the nQr inclinatiQn that my bQX happens tQ chQQse, are adjustable, but the flQQr is tQQ tricky mal range Qf vertical arm mQvement. but it alsQ tracks like a breeze at almQst fQr me tQ keep up with. My New YQrk -:NQW this last is a vital- PQint. A: nQn nQ stylus fQrce.- which is an especial bless apartment building, fQr example, is r ela linear spring-and we have plenty Qf them ing fQr me. tively new and built Qn a steel frame, but in milliQns Qf Qlder changers, pulling the Y Qu'll r emember the Qld Canby LQQse the flQQrs rQll and heave like a stQrmy sea. arm upward against its Qwn weight-dras FIQQrbQard test. I'd almQst fQrgQtten it; BQQkcases lean Qut frQm the walls and tically increases stylus fQrce as a changer but I suddenly became aware that this arm must be prQPped, tennis balls and snch arm is lifted upward, IQwers it as the arm was tracking merrily Qnward even while tend tQ rQll dQwnhill tQ the center Qf the drQPS. In the Qld days when heavy stylus I trQd heavily Qn the same Qld springy rQQm. Each time my table gets mQved an fQrces were measured mQstly in Qunces, the bQards that in the past have SQ Qften inch Qr SQ fQr cleaning Qr the like, the legs difference was a drQP in the bucket, tQ thrQwn gQQd cartridges intQ a tizzy Qf are left with at least Qne and Qften tWQ Qf mix metaphQrs. But nQw, when stereQ pres grQQve hQPping. Y QU can't bQther this arm; them dangling in the air an eighth-inch sures are SQ slight and stereQ styli are as as I understand it, the shQcks and vibra Qr SQ. sharp as needles-real needles-the slight tiQns SQrt Qf cancel Qut-they hit bQth I'm aware that gQQd engineers always est variatiQn is seriQus. (And hQW many ends Qf the area, bQth sides Qf the pivQt, true up all turntable equipment. I dQn't dQzens Qf springs can yQU remember that and neutralize each Qther, A-A'. That is thQugh I try. Neither dQes the public, I'll gave Qne reading as yQU tightened them an inherently excellent virtue that shQuld wager. SQ: I'm all fQr any arm that will up, slipped tQ an altQgether different Qne recQmmend any arm tQ yQU which can play uphill and, mQre impQrtant, will play when the adjustment was turned the Qther bQast it. GrQQve-jumping frQm external withQut side-pull and at CQrrect pressure way') shQcks and reSQnances is still a maj Qr regardless Qf the billQwing wQQden waves Present stereQ changers have dQne in bQther in present-day hQme hi-fi Qf many in the nQrmal American flQQr! geniQUS things tQ get away frQm this, tQ sQrts, fancy and IQwbrQw alil 44 AUDIO . - MARCH , 1960 AUDAX Audax systems were planned with intE~iiigence , styled ented P araftex speaker con~ suspension permits infalli· with boldness, built with precision. They are everything ble handling of the audio l'ange. The ducted acoustic slot an outstanding speaker should be ... a welcome combi in the enclosure assures bass free of annoying boom. nation of unusual beauty and versatility. " a truly orig And, Audax is not a "power hog" ... it will operate with inal achievement in furniture design. The 3-dimensional lower powered amplifiers! ' Dynel Acoustiscreenis a distinctive new face in speaker You're secure in choosing Audax . .. secure in knowing grilles, available in vertical or horizontal patterns to that you own the ultimate in speaker sound, and styling. preserve the "honest" design. Place Auda* as you want " CA-BO - 2 full ?'ange 8" speak ers and mat ched - tw~e t e?·. $99.95 • -on shelves, tables, in cabinets,or: free-st anding. Legs ' CA-HiO, above -'- 2 ·f ull ?w;g e 1 (j" speake?'s .. ' .. ' , are available, if desired. All Audax Paraftex Speaker and 2 matched tweeters. $139.95 •... Fo?· systems are custom finished in oiled walnut. the biggest and bes t sound in the smallest package! M odel CA-60, right- 9%" x 10" 'Audax sound is "natural" and spacious (Audax is more x 18". 859.95 speaj:{er than many units three times larg,er) . The pat- Send for free colorful brochure. AUDAX, DIVISION OF REK·O·KUT CO., INC. Dept. A-3, 38-19 I08th St., Corona 68, N. Y. Name: ______AUDAX • DIVISION OF REK~ O-KUT CO., INC. ~ , IT' Address ______\!J 38-19 I08th St., Corona 68, N. Y. City Zone_state I ;------~ ------~ ------~ ---~~!~, Export: Morhan Corp., 458 Broadway, N, y, 13 • Canada : Atlas Radio Corp" 50 Wingold Ave., Toronto il,\:OPI,O' - . ' , MARCIf, ' 1900 45 varies as the square of voltage, the effec tive "power" scale is spr ead out on a volt meter scale. For greatest accuracy, a cali brated oscilloscope should be used. I HFM Standards have not yet been pro mulgated for measurements of intermodu lation, distortion, and until recently we have applied our own rating to amplifier output on t he basis of the power at which 1M elistortion was 2.0 per cent. Some engi neers believe that present 1M methods (two frequencies, 60 and 7000 cps, with the higher tone 12 elb below the lower) serve only as a measure of low-frequency dis tortion of the amplifier, while others (in cluding ourselves) believe that 1M measure ments give a closer measure of the audible distortion in an amplifier than do harmonic measurements, since music is largely har moillc in structure and harmonic distortion is not so detrimental to quality as is 1M. This argument has not yet been resolved in PR.Ofll the IHFM, although many other r eputable organizations subscribe to 1M measure H. H. SCOTT 299 is to the credit of Scott. In accordance with the Standards, there ments as being perfectly valid-notably STEREO AMPLIFIER fore, the latest measuremen t on the 299 the SMPTE, Westrex, and Altec. In any gives a figure of 18.6 watts on one channel case, we made 1M measnrements on the 299, and at 1, 5, 10, and 15 watts the In the November, 1959, issue, this section and 19.1 watts 0 11 the other at 0.8 per cent profiled a Scott 299 amplifier which was distortion. . distortions were 0.13, 0.24, 0.33, and 0.64 one of the earliest units built and which Power Bandwidth is the term which is per cent, reaching 1 per cent at 16.6 watts had been in onr hands since the previous used to specify the performance of an and 2 per cent at 18.0 watts. Thus we would April-in fact, the company had no record :1mplifier at the frequency extremes, and is normally r ate t his amplifier at 18 watts. of our having received it for test and stated as the highest and lowest frequencies One other measurement relating to power wondered how we had gotten it. Since the at which the distortiou is the rated value output is described in t he IHFM Stand measurements were not expressed in the (in this case, 0.8 per cent) at 3 diJ below ards, and this gives a higher numerical now standardized IHFM term, H. H . Scott the rated output, which is 17 watts for the value than Continuous Power Output. The IllC. forwarded us two recent muts to be 299, according to the manufacturer. On the term "Music Power Output". is given to a checkecl and rated under the IHFM Stand two channels, we measured 33 and 22 cps, measmement made with "significant supply ards. respectively, as having the 0.8 pel' cent dis voltages maintained at the same value as Measurements under these Standards be tortion at 8.5 watts (3 db below the rated they were under no-signal conditions." come r ather involved, as is apparent to 17) for the low end, and 22,000 and some Actually, this is an important figure, since anyone who has read t hem carefnlly. For value beyond the range of our distortion the ability of an amplifier to handle in the specification of outpnt, power in watts measuring equipment. Therefore, the poor stantaneous peaks of power is important is measured for a rated percentage of dis est Power Bandwidth figure wonld be 33 " 'ith music waveforms where tones such as tortion, which for the Scott amplifier is 0.8 to 22,000 cps. a piano have a high peak valne but the pel' cent, in contrast to the r ecently adopted It should be rea. onably obvious that integrated power output over any appreci standard of the Electronic Industry Asso measurement accuracy attains a rather high able amount of tiille is considerably less. ciation which calls for a distortion of 5 oI'der when variations of less than 1 db are Thus, for example, it is likely that an per cent. We still believe firmly that all encountered; in this range, for example, amplifier with an MPO rating of 20 watts high fidelity component manufacturers f rom 16 to 20 watts is only 1 db. Power and a continuous power r ating of 15 watts shonld rate their. products' outputs in "Hi outputs are usually calculated from voltage would undoubtedly sound better than a Fi Watts," which we have heretofore pro measurements made across a load resistol' 15-watt amplifier with a MPO rating of only 16 watts. The nsual (and simplest) posed as being the power output at 1 per (which in itself s hO~tlcl be a pure resistance, cent distortion, in contrast to the much which is almost impossible to obtain; a method of making this measurement is to . introduce a sh unting resistor across any higher figure us ~ d by most of the so-can ed wire-wound resistor has considerable in series resista.nce or choke in the power "pac~age" manufacturers_ However, 0.8 pel' ductance, and this can cause unusual effects supply so that under high power outputs, cent I S eve:1 better than 1 pel' cent, which in the higher frequencies) and since pawer when the output stage draws mOTe current than in the no-signal condition, the voltage applieel to the outpnt tubes is the same as in the no-signal condition without the shunting resistor. Fa.ctors tending toward a high MPO rating are a large storage capacitor (the one f rom the output-stage supply tap to ground) and a low value of series resistance between rectifier tube and the supply tap. On the 299 measured, we founel the MPO rating to be 21.2 watts on one channel and 22.0 on the other, both at 0.8 per cent distortion at 1000 cps, in accordance with the Standards. IHFM Standards specify that hUIll and noise measurements shall be made using the weighted 40-db (A) curve of ASA Standard Z24.3-1944. The 299 measured ' ...... • ... ·· M · .• showeel, under these conditions, a hum and lIoise level of - 69 db on the phono and ! .. ! ...! .. tape-head inputs and of - 86 db on the high-level inputs, both figures being sigillfi ~ cantly better than stated in the earlier ...- .~:.;. C· ·'- PROFILE. For the information of anyone ... - . .' , ~ 0 ~..••• ~' -. - who cares to dnplicate hum anel noise measurements in accordance with IHFM Standards, a circnit consisting of a .03-uf capacitor in series with 10,000 ohms cim be used ahead of the high-impedance VTVM, which is then cOllllected across the 10,000-ohm resistor. This will approximate the 40-db (A) curve of the ASA Standard. Fig . 1. H. H. Scott Mode l 299 Stere o Amplifier. 0-24 46 AUDIO • MARCH , 1960 RS·406 12" Acoustical labyrinth System When a speaker system has the unique facility of repro ducing every sound within the effective hearing range without adding or subtracting from the music-you en joy " Integrity in Music." This facility in Stromberg Carlson's Acoustical Labyrinth®-our famous quarter wave length duct enclosure-results in five systems which offer you maximum performance. Most popular of the five is model RS-406. It has a 12" soft skiver woofer, a 5/1 mid-range and an induction tweeter-all Stromberg-Carlson products. Its e£fectiye frequency range is 30 to 20,000 cps. Over the range of 48 to 18,000 cps its 1M distortion is 0.8 %. It's shelf size, too-22}f;" x 13%" face, 12%" deep. Complete with crossover network, set up ahd prewired at the fac tory for only $119.95.* Other Acoustical Labyrinth systems range from the RS-401 with 8" woofer plus cone tweeter, at $44.95,* to the RS-424, a superb system featuring a 15" woofer, for $199.95.* Decorator cabinets in contemporary, period and traditional styles and finishes are available for all Acoustical Labyrinth systems. Stromberg-Carlson now offers 16 equipment cabinets in a wide variety of styles and finishes. They are de signed to house complete Stromberg-Carlson stereo component systems and are factory assembled. They reproduce as faithfully as separately mounted compo nents because of a unique mounting method that iso lates the speaker systems from the other sensitive components. See your dealer (in Yellow Pages) or write for a complete component and cabinet catalog to: 1418-03 North Goodman St., Roch ester 3, New York. * Prices audiophile net, Zone 1, subject to change. Decorator cab· inets extra. "There is nothing finer than a Stromberg-Carlson" STROMBERG-CARLSON A DIVISION OF GENERAL DYNAMICS AUDIO : . MARCIf,' 19~ 47 . \.:~. ~.:.... EDWARD TATNAll· CANBY* Is raw and somehow collegiate in sound, mu Bach. You can tell, by the way it sounds, the FORWARD WITH THE CLASSICS sically unpolished, the ancient Concert Hall "busy" effects, the ultra-simple harmonies, British recording Is done with a tiny chorus the quick arrival at the' rudimentary "second Handel: Royal Fireworks Suite; Water in madrigal style. theme" idea .. . but, as I say. these things Music Suite. Phila. Orch. Ormandy. The complementatry drama of grand phi are heard much more easily than they are Columbia MS 6095 stereo losophising that Is Handel's most maguificent described. ' dramatic tool of all is gorgeously handled by The musicologists have laboriously dated This is unregenerate Handel for those who Mr. Boepple-those great eight-part choruses this music as "before 1781." Boosey & Hawkes go nuts over Bach-Stokowski. I suppose there of comment, glorifying the Lord and hit! publish its score as of 1767, "without," as really Is a continuing market for such stuff, works, the big, fugal climaxes recounting the notes say, "quoting evidence to support" among people who have discovered that old what has been accomplished. Good stuff here, the date. Handel isn't so bad if you make him sound even with a few amateurish yawps and shouts Well, the evidence is there all right. It's enough like Rachmaninoff. To tell the truth. from over-enthusiastic _ singers and some right In the sound of the music. Try it and I was once nuts myself (aged fifteen) over bloopers of a minor sort in the orchestra. see, In pleasing stereo, nicely recorded. the Hamilton Harty arrangements (and the The stereo is particularly good and useful Beecham ones) of the Fire and Water music. In this double-chorus music, close-up miklng But I went on to higher things and so, too, adding more Impact to the intended separa Chopin: The Fourteen Waltzes. Alfred have we all as a group. Even kids now like tion of the two choral groups. Even the or Cortot, piano. (Recorded in 1934). Handel himself, these days, minus · doctoring. chestra is nicely spread out, though close. Angel COLH 32 The Fireworks Suite is in the Harty ar Miriam Burton, Betty Allen, and Leslie What an extraoldinary experience this reo rangment, played here with the largest pos Chabay are the three competent soloists, all issue turns out to be! To hear this great sible forces and the biggest possible blur. very musical If not exactly Handel-type sing pianist of another time play these works In The Water Music Is listed as arranged by ers. There's organ and harpsichord (Prince his prime, in a manner that simply does not Ormandy; the sound Is that of the familiar Joseph, Conant) nicely balanced. One soloist exist any more, is a joy Indeed and a revela Harty arrangement, touched up and en makes a serious mistake In one aria, hut I'll tion of the true meaning of the waltz as hanced with extra ultraviolet. Dreadful-ab bet you can't find it, so deft was the recovery, Chopin composed It. solutely dreadful, Is all I can say. unless you follow w.ith a score and have razor True, Cortot played a full lnindred yea rs (P.S. If huge sales on this disc help pay sharp ears for parallel f1f~hs. after the composer himself, and we today have Columbia for the cost of some of Its more ; worthy offerings, I can't complain too hard.) added a mere quarter century to the span. Haydn: Horn Concerto in D; Trumpet Nevertheless, time's horizon's are narrow, . (P.P.S. I forgot-there's also one of those twenty-five years is just about the full span dirge-like Corelli suites that date from the Concerto in E Flat. K. Arnold, horn, W. of living memory. and in tbis last quarter times before we had discovered that Corelli Gleisle, trumpet; Pro Musica Orch. Stutt~ century the world-and music too--has was a human being.) gart, Reinhardt. changed with frightening speed. Vox STDL 500.480 stereo It's hard for me to believe that in those Handel: Israel in Egypt. Dessoff Choirs, very days, the mid-thirties, I myself bought soloists, Symphony of the Air, Boepple. This attractive and simple album is one of a companion VictOr 78-rpm album by Cortot, Vox STPL 511.642 stereo a new international-type series on Vox, the 24 Chopin Preludes, and found them very (Music of Five Centuries), manufactured for dull, in my youthful snobbishness! Chopin This is the first recording of the big Hane sale in various countries,' the notes in this himself was unbearable to me at that age; del piece (double chorus, three soloists and. albuqI printed •.in both English and :Fr~nch. _now, with tlJ.es~ many yea~s' of listenipg be orchestra) to do justice to its dramatic force . 'After so many garish COlor-covers; this one's hind me, I -marvel at the fluid, alive sound ""':the very essence of the music as first con plain light blue with a pink label stands out of these waltzes, and so will you. Live and ceived. I'm prejudiced, of course; I sang in by reason of Its very simplicity. (But the learn. this performance as a Chorus II tenor. cover tends to curl a bit.) My eye likes it. Above all, Cortot, in the manner of his The performance was recorded at a con An interesting listening-point comes up in time (which was the early part of the cen cert, necessarily (with some re-recording respect to these two works. The musicological tury, beginning even before 1900), was a afterwards), and suffers in some respects, In scholarship quoted in the notes tries hard to master ~f what we call rubato, !l most In evitably-though not from coughs and noise; pin down the born work as to its problemati adequate word used to describe the subtle an attentive audience and good tape editing cal date, but isn't very convincing; the fa art of Irregularity ' in the time values of per have virutally removed all sense of audience miliar Trumpet concerto is well known as a formed music. R1tbato is taboo nowadays in interference. The sound, picked up 'from fairly late-Haydn piece, from 1796, the time ,of the most playing; when it does appear, it is no c10secup mikes on' the stage, Is spatially not big oratorios ("The Creation" and "The Sea longer the old sort, or seems stlfl', false, ex as ample as it might be and some sections of sons"), written after the last of tbe sym aggerated and uneasy-the art of It is largely the large singing chorus are a bit too close phonies. lost. Waltz time Is waltz time, and that Is for a good- blend, notably the tenors of Cho.rus Now I malntallLthat any good listener who that. But Cortot's waltzes are incredible. You I. But the dramatic' impact of an exciting, lIas heard a lot of Haydn, Mozart, Bach, and can't possibly "beat time" to tllem; no two arresting performance Is captured beautifully. tbe like can spot the approximate dates of beats are alike; many are virtually: non-exist Even the sUght raggedness here and there of tbese two works without any help at all from ent, deftly shortened or even omitted where a stage performance not subject to leisurely scholarship, just by their sheer sound. If they have no expressive function, others are re-takes will please any Informed listener who you've listened. to the period, you'll recognize subtly lengthened, for the most poignantly Is after the meat of the music, merely by its tbe styles as you ' can spot, say, a family pho lingering accents on those big moments of genuineness and sincerity. tograph, of the 1920'~ by tne clothes the rela supreme poetry that make the waltzes live. And it is the m.eat that we hear, no two tives wear as well as by their familiar faces. The music under Cortot's hands seems to fiy. ways about it. This predominantly choral No trouble with the Trumpet Concerto, as light as air, passionate, musing, poetl(', piece (only a few scattered solo arias) paints which is here played admirably and without ultra-intense but gentle and winsome too. Ex the great events in Egypt-the plagues, the those once-usual modernizing alterations. This traordinary ! crossing of the )led Sea _On dry land, the over is obviously, In the listening, of the, shall 1 No, I don't suppose we can prove that whelming of Pharaoh's soldiers in the 1I00d say, almost-Beethoven period. Being Haydn, Chopin himself played like this. The printed with almost violently dramatic force, cumula it is not as emotional, as Romantic, as much music doesn't Ind;cate it; and wouldn't In tively, one thing hard upon another, building late Mozart. But many a passage is already any case. But Cortot surely persuades us that excitement. Boepple, this conductor, piles up technically beyond Mozart, sounding like early this must be the -grand tradition, the true the tension and draws out the pictorial magic Beethoven. And all the way through, you'll Intent of the music--it couldn't be otherwise! straight through-where so many perform hear tunes right out of the "Creation"-if It is a way of playing that Is now beyond ances treat each piece as a static, separate you know that work. Haydn, all right, even if recapture, except through such living record "oratorio" number, minus a thought of drama. you didn't get told of it officially. Ings as thls one. (See the Incredible Huddersfield recording, on The Horn concerto is much earlier-clearly, Technically, the piano sound Is excellent, Angel.) Other recordings have aimed In this to any listening ear. It belongs in tbat inter scarcely ever distorted even in the loudest direction-but the Westminster Utah version esting In-between period, before Mozart (or parts. Surface noise has been almost elimi In his childhood), dominated by the Stamitzes nated in the LP processing, no doubt from * 780 GTeenwiqh St., New Yor7c 14, N. Y. and then the Bach ROns, notably K. P. E. tlie original masters. 48 AUDIO • MARCH, 1960 •••••••••••••• • from t::::ii'FJ : AUDIO crill .. • FIDELIT~ . RECORDS KING • NEW RELEASES. •• music for everyone's taste on AUDIO FIDELITY ... custom recording techniques. • outstanding performers ... matchless purity in sound. • the ultimate in high fidelity listening pleasure from ..• LOUIS ARMSTRONG plays jazz favorites born in the early .1900's . . . immortal clas· the highest standard in high fidelity! sics that have withstood the test of time .. . music that is as vibrantly alive today as the day it was written. Satchmo played all the • AFSD INDICATES RECORDS AVAILABLE IN STEREO ••• $6.95 selections in this album with King Oliver, and, many of the selections were written by • EACH 12 INCH LONG PLAY ••• $5.95 • King Oliver himself. Listen now to Louis Armstrong play such classics as: "Saint • James Infirmary," "Frankie & Johnny," " Jelly Roll Blues," "Big Butter & Egg Man," " Hot Time in the Old Town Tonight," "Panama," • ••••••• " I Ain't Got · Nobody," " Dr. Jazz," " Drop POIANO RAGTIME with That Sack" and others. ••••••••the Phenomenal •• ' . AFLP 1930/IiFSD 5930 YOLo II • DUBBS OP DIlIIBLUD' . ~ • < • • PIANO RAGTIME .. . DUKES OF DIXIE THE HAPPY SOUND OF RAGTIME . .. LAND. New Orleans ... storyville •. . HARRY BREUER. The startling and ex high steppin' music with the plunking citing sounds of g enuine Ragtime in • piano, whompin' tuba and sliding trom effervescent rhythm played in the au· bones. Selections include: " Tiger Rag," thentic happy manner of mallet virtuoso "Original Dixieland One Step," and Harry Breuer. Se lections inclu de: • Kansas Cit y Stomp." "Temptation Rag," "Bugle Call Rag," AFLP 1928/AFSD 5928 12th Street Rag" and "Dill Pickles." AFLP 1912/AFSD 5912 Hear the rich, resonant voice of ARTHUR • • TRACY ••• THE STREET SINGER singing • Marta, the song h e made so famous. Hear also in brilliant high fidelity, renditions of • • " September Song" , "Because", "You Are My • Heart's Delight" , "You'll Never Walk Alone", and "Beautiful Love" . • • AFLP 1929/AFSD 5929 • • • •••••••OTHER NEW RELEASES III • • ITALIAN STREET SINGER .. . Val • Valenti . . . a vibrant soari'lg voice singing such favorites as "Core 'ngrato", HMattinata" and "Tiri Tomba". • • AFLP 1902/AFSD 5902 • • JO BASILE his Accordion and Or With his big band ... LIONEL HAMP- Go west with JOHNNY PULEO and his chestra in Accordion d' Espana playing • TON at the vibes ... playing "Hamp's Harmonica Gang while they play "Red • " Lady of Spain" , "Doce Cascabeles" , and "Pamplonica". • Mambo", '''Air Mail Special", and "Hey River Valley" , " Yellow Rose of Texas" , Ba Ba Re Bop". and "On Top of Old Smokey", etc. AFLP 1870/AFSD 5870 • AFLP 1913/AFSD 5913 AFLP 1919/AFSD 5919 • • Carnegie Hall concert of the phe· • nomenal DUKES OF DIXIELAND!!! Selections include " Muskrat Ramble", " Royal Garden Blues" and "Moritat". • • AFLP 1918/AFSD 5918 • a complete catalog Is available from: • EDDIE JACKSON .. . the struttin' EPARTMENT vaudevillian singing "Waitin' for the .• •••••••••A-3 • Robert E. Lee" , "Bill Bailey", and • 7 ,70 ELEVENTH AVE., N. Y.19, N. Y. "Sweet Geor:gia Brown". AFLP 1909/AFSD 5909 • arne ...... • Outstanding artistry ... unequalled virtuosity ..• LARRY ADLER . . . play· ...... •... .• ...... • ...... •...... • ~i:v~:~h~~~S"su;':T~r ~~~~:;~~' ::n1: .• ·· ··iiii·· ·iiif··iiii···.···.···.··.··••••••••• AUDIO • . MARCH; 1960 49 Brahms and Strauss Lieder. Irmgard Seefried; Erik Werba, pf. Deutsche Grammophon DGS 712018 stereo This is just one mo re in the long series of records by t his extraordina ry singer, bu t it is as uniquely exciting as a ny in t he past. ' ¥ bat Duikes a great Singer ? F irst of all, a keen lllu sical ear-even before a great voice; but along wit h the ear, in lockstep with it, there must be persona li ty, emotional intens i ty, paSSionate devotion. Seefried has a strange, alm ost unearthly ins trument not like any I've ever heard before; I keep thi nking that in some way, it is a t omboy voice, a wild, passionate, lusty, peasant-like, li ttle boy voice t hat quite often squeaks and yawps in strangely homely t ones, yet somehow pro jects a musical sincerity and passion that also-reminds me of, a peasant, J oan of Arc, Berna rd Shaw's J oan, full of fire. She makes a new t hing of every song she sings, personalizing the mu sic, bending t he line and shape (wi thin acceptable bou nds ) to fit her peasant·pure delivery, the fl at, wobble free low t ones, the almost shrieking high tones, utterly t rue in pitch and emotional projection. This lit tle gal will never bore you with her singing ! E rik Werba is her ever-exclleent accompan ist. The st ereo sound is so-so, the piano rather distant and lacking in bass, t he voice rather too noticeably off t o one s ide fo r natural real Best ism. In two minutes yO U'll forget a ll (lQ Ollt such minor consjderatiollg, for Strauss: Don Quixote; Till Eulenspieg el. Be rlin Philharmonic, Ke mpe. Capitol SG 7190 stereo T his is a limpid a nd lovely reco rding of built-in the well known tone poems, leisurely, relaxed, low-voltage yet never dul l. Those who have been nurtured on the high-tension Strauss of Fritz Reiner (on RCA Victor) may find t his systems kind of Strauss hard to accept for awh ile-it is very differen t. Bu t, length aside, it is well wor thwhile, Reiner notWithstanding (and I think Reiner is t he g reatest Strauss man alive) . When planning a built-in high fidelity system, Length is the main difficulty in "Don it is wise to specify speakers that work best in Quixot e." It never fails to fascinate me at the simple, easily-constructed enclosures. beginning, this work-a nd I am always driven t o saturation long before it ends. SlI ch end This not only saves time and money in less spinning-ou t of a good idea! Fortunately, carpentry but avoids the possibility of disappointing a recording may be played in bits a nd pieces to taste ; Capitol (ElIlI) obliges here by performance caused by unavoidable alterations spli tting the big piece onto two s ides. Maybe to dimensions of labyrinths, folded horns, you'll never get t o side 2. But you should, fo r "T ill E ulenspiegel" and other tricky config urations. gets its corresponding pleasing and gentle Bozak speakers are the ideal choice - t rea tment t here, in the same manuel'. I n both works t he stereo sound is quite lovely, a gen they are designed to give optimum results tle, big, shiny sonnd but somehow very natu from the simplest enclosure - the infinite baffle. ral and modest, the many solo passages throughout the orchestra nicely located a nd You can listen to a Bozak in a showroom related in the comfortably big space. Excel and be assured of obtaining equally fine sound lent. from your built-in Bozak System. Bozak speake-rs are available as individual Gershwin: Rhapsody in Blue; American in Paris. l e onard Bernstein, Col. Sym units and in a variety of fully-wired, phony, N.Y. Philharmonic. ready to install panel systems. They are Columbia MS 6091 stereo the best you can buy, yet surprisingly reasonable Here is the familia r Gershwin pai r in new in price. Visit a Bozak Franchised Dealer soon style stereo, with Berns tein t he ' pianist in the and discuss your requirements. "Rhapsody" and the conductor of both, and never has Geshwin been given t he red carpet treatment so fully. Botb works have a huge, monumentally symphonic air to them, bathed in a vas't liveness according to currently pre vailing t astes for "symphonic" mus ic of the higher classical sor t. Both have excellent jazz style soloists- the clarinet and trumpet in the " Rhapsody" a re very much in style-but tbey a re distantly sit uated, far off in t he vast con cert-ball spaces, melting in a bu ttery sort of way into t he great, golden symphonic sound. Nope-this I don't li ke. I keep remember ing (bnt can't fi nd) the ancient Whiteman da nce band version of the "Rhap. ody''' on 78-rpm records, done up in the d ry 'T we nties styl e, snazzy, hard, close-to, without a trace of golden li veness' or romantic bigness. T his new version s.eems just r ight fo r a super colossal movie spectacul a r, which isn't my T H E V E R Y B E S T N M U S c idea of the Gershwin sound at all. '50 AUDIO • MARCH , 1960 To be sure, Bernstein has an unerring sense of t he right musical approach for the lilting, tipsy parts and he has picked soloists who play right, too, minus any symphonic snob bishness. (Yet even so, that curiously senti mental, Chopinesque streak in Bernstein shows up here in the slow piano "blues" sec tions. ) The musical sound is generally right, t herefore, if pretty thick in texture. But why, then, does Columbia have to give it the huge symphonic treatment? I suppose because this was Gershwin trying hard to go classical! That must be t he thinking, anyhow-unless it's done this way simply out of sheer habit, big Ii veness being standard for any symphony orchestra m icrophoning nowadays. Perhaps if t he disc had been done as a pops record, in another department, it m ight have had a more appropriate close-up treat ment in t he miking. But that wouldn't do not for the Philharmonic aud Bernstein. The "eal t rouble is that the Gershwin music is in itself a hybrid type, neither pops nOt· claSSical, and t herefore Simply will not fit into t he machinery of either sort in the con ventional way. Seems as though Columbia could have coped with this a bit more imagi natively-nobody wants a real pops stereo recording, with the clarinet one inch from one mike and the wah-wah trumpet a half inch f rom t he other; but something could have been done to give a better and truer pops-jazz fla\'or to these works in their re corded sound. Bartok: Piano Concerti # 2 and #3. Gyorgi Sandor; Pro Musica Orch. Vienna, Gielen. Vox STPL 511.490 stereo What wonderfully zestful music this Bar tok is-now that we have g rown to t he point where we can take it without being horrified ! The Second Concerto is the violent one, the most hi-figenic, out of the brassy, noisy 'Twenties and just before that sudden return to a softer neat'-Roma nticism that came about in the whole musical world along with the Great Depression. If you have enjoyed the whirlwind music of t he Bartok Music for Strings, Percussion and Celesta of sligh tly later (1935), you'll fi nd this piece dear to your hi-a heart. It's from 1931, and never were such marvelously furious sound gener ated in a piano and an orchestra. The open ing movement uses winds a lone, the second movement is for strings and the fin al move FIRST CHOICE ment t Ul'l1S on all the stops, with everything. The Third Concerto is of a much gentlet· natu re, from Bartok's last period, bu t this, too, has overwhelming attractions fo r those FOR LASTING ECONOMY who know the Concerto for Orchestra of a year earlier. Precision design and rugged construction to meet the· exacting, I won't qualify the above enthusiasm one professional requirements of the broadcast industry assure long, bit as far as the fi of this disc is concerned trouble-free life for true economy. it's a fine stereo, wisely and effectively mil'ed with a good Iiveness but plenty of sharp, mod ern-style edge as well, the piano situated Consistently high performance and virtually trouble-free operation oddly off to the right and in excellent balance of the Ampex 351 have established it as the first choice of not only with t he inciSive orchestra . (It was to the broadcasters, but educators, professional recording studios, research right as I played it , anyhow.) But the per formances are not up to my description, alas. laboratories, religious and business organizations_ I wish they were. The pianist, Sandor, is a Hungarian and Actual case histories document the fact that Ampex, on a cost-per sometimes I think only a Hungaria n can play. operating-hour basis, is the most economical recorder made. Write this music. Sandor produces t he requis ite f uri ously, his fingers fly like the wind. But that for new comprehensive catalog 2031. isn't enough. The peculiar thing about Bartok is the immense, profound, Beethoven-like Ampex Professional Tape Recorders have humanity in musical terms tha t lurks just behind all the sound and fury. It's enough to been selected for official use at 1960 Winter say that Sandor simply does not evoke that higher musical sense, as I hear it. His fingers Olympics, Squaw Valley, California a re fast and furious, but the sense is miSS ing. (He's better in the Third Concerto, a simpler and more easily projected work, which has been a specialty with him in the past.) As for the orchestra, it betrays what seems to me a Viennese softness-quite unlil,e San dor's hardness. The notes a re all there, but the spirit is diffident, even a bit squeamish. An American orchestra would do far better in understanding, I think. However-unless you know these works fairly intimately from other performances, don't let my hair-splitting bother you too AUDIO PRODUCTS DIVISION \ AMPEX I much. The sound on this disc is terrific in AMPEX PROFESSIONAL PRODUCTS COMPANY stereo, which is enough to get much of Bar tok's Impact over. 934 CHARTER STREET RED woo D CIT Y, CAL I FOR N I A AUDIO • MARCH , 1960 51 I can state positive things about the two BACK T HROUGH OPERA recordings, which are stril,ingly unlike in Strauss : Der Rosenkavalier. Sche ch, See technique. The stereo " Lucia" is one of those experiments in stage·distance stereo recording, fried, Streich, Fischer-Dieskau, Boehme; with the singers mostly off in a big space, Sax on State Orch., Boehm. not far In front of the big orchestra, the Deutsche G rammophon DGSR 7301 (4) whole thing immersed in the expected huge stereo liveness. Frankly, I think the technique Is unsnccessful here--even though it might be Fanciers of this famous opera have their claimed that this is nearer to the original in· own special favorites for its important roles tention. But keep in mind that stereo record --the Feldmarscllallin, Bal"On ~ebs, the young ing has its own rules and values, not all of Octavian (sung by a soprano}--and the opera them completely worked out as yet; it depends even seems to have, like "Carmen," a number as much on illusion as any JDono recording, of distinct nat'ional-myles, surprisingly differ must operate on its own, via its own advan ent in view of the now·universal world ex tages, as must mono. change of artists via air travel. These singers, even with stereo space to New Yorkers, for example, may not find help them, are "off-mike," decidedly; their this ail·German version quite what t he Met immediacy of impact snffers from far too might order; but I found it a moving and much ring and blur. (Is It my correct im very musical performance on its own merits. pression that La Callas manages to get a bit interestingly cast with important German closer to the mikes than anyone else? Maybe Here's the super-sensitive voices who know how to act via the musical just my imagination.) The chorus and or medium. In addition, It is recorded in a chestra are both good in this big space. Not Bell Carillon S tereo Tuner strikingly dramatic manner, the Singers so the solos. very close to the stereo mikes that the rapid· The "1I1anon Lescau t" from Italy Is not fire sung "conversations" of the Strauss only done in mono but is served itp in a to match your Bell idiom are startlingly personal and real, like drier, closer microphoning, for considerably dialogue in film and TV. Ililproved effect, I would say. Opera needs Carillon Stereo Amplifier The orchestm, in this set-up, is rela ti vely close·up miking. even in stereo. Of these two ·neutral in space, at some distance in tbe I would immed iately pick the mono recording background. It is active enough, decidedly, as the more effective. and its details are entirely clear and beau tifully projected in sound--bnt the violently close foreground impact of the singing voices Bizet: Carmen. Rubio, S imone au, Alarie, • sets It off a bit, somewhat as the unseen or Rehfuss; Chorus, O rch. Concerts d.e Paris, chestra plays in many a film sequence while L ~ Conte. ' Epic SC 6035 (4) spoken dialt>g goes on in the foreground. Of cours.e tbis Is wholly foreign ,to the Ol"lginal This is a rousing gbod "Carnlen," even in musical intention as of the opera house, but mono. Indeed, It is an ideal mono·style oper in terms of the new medium of bi~fi stereo atic recording, with maximum advantage sound it is bighly effec!h'e. The only detract taken of the standard operatic know·how de Ing fault I can name Is that to some extent veloped over so many years, prior to stereo. the close·up voices are mOre breath·y, more The performance is thoroughly French even stt·ident than Strauss might have envisioned, thongh, oddly, the heroine Is actually Spanish the lovely tones less lovely at such close (as is Victoria de los Angeles in the rh·al range. The extra dramatic (and musical ) im recording) and one male lead is Canadian, the CARillON Mo del 6060 2-channel Stereo Amplifier other German. The production Is, so to speal" . . . 60 watts power ... plays stereo tapes, stereo pact makes up for it, I say. The albnm is handsomely got up in an ap a stylish one a nd full of life. The Spanish records, stereo FM-AM tuner. The Carillon does Carmen herself has the rich, wobbly voice we eve,·ything you want . .. has all the features propriate orchid purple, the inner plastic rec· ord sleeves also of the same perfumed color, associate with the role and she is full of you need, including built- in pre-amplifiers .. . vigor, too, even when fate closes in; the the perfect match for the Carillon Stereo Tuner. as is the large and informative booklet. Com· plete text and translation makes it a real superb voice of Leopold Simoneau makes a pleasure to follow the opera's continuity. A paSSionate suitor for this frivolous· tragiC NOW ••. RECORD STER EO ON TAPE to soloists, all are excellent in their roles and heroine. Diction throughou t (with close·to wonderfull y dramatic, but Irmgard Seefried's microphoning) is excellent and ultra·clear; Octavian is quite extraordinary, though not those who know French will have no need of at all in the more or Jess expected style for the libretto, though it is included. the role. Her strangely boyish, flat tones may The orchestra and chorus are lively, too, bother some who know the opera well, bu t bnt not of first-rate calibre; the opera is car most of us will enjoy her sheer musicality and ried here by its enterprising soloists. The dramatic fervor. chorus isn't overly important, but it could sing with better pitch. The orchestra tends to be metronomic when it plays alone, which Donizetti: Lucia di Lammermoor. Callas, Is most likely the fault of the conductor. His Taglia vini, etc., Phil harmonia Chorus accompaniment of the singers, though, is im and Orch., Se rafin. peccable. All in all, an enjoyable "Carmen." Angel 3601 BI L (2) stereo BELL Ste reo Tape Transpo rt. Nine models ... for Puccini: Manon lescaut. Callas, di Ste Bizet: Carmen. De los Angele s, Gedda, stereo playback and recording . .. 2-track and fano, etc. La Scala company , Serafin. Blanc, M iche au, etc.; Orch. Nat. d e la 4-track stereo tapes. Only popular-priced stereo A ngel 3564 C/ l (3) mono tape transports with such professional features Rad iodiffus ion Francaise, Beecham. as 3 heavy-duty motors for positive tape con I'm not much of an Italian opera expert Ca p itol SGCR 7207 (3) stereo trol-Auto-Stop Mechanism - electro-dynamic and will not pretend to judge t hese perform· braking. Bell stereo tape transport . . . best way ances in the whole; what interests me is the I had time to play a good part of this one to complete your music system. Callas voice; she has the lead part in both before deadline closed In--after I had writ- operas and dominates both recordings, one . ten about the Epic recording preceding. This For fut! information about outstanding stereo made in England, the other in Italy. one has t he magic name of Beecham attached components by Bet!, send coupon below. I'm not a Callas fan. In fact, all I have to to it (via EMI in England) and there Is no say here is simply that for my ear she has doubt of his decisive part in its powerful Im one of t he most unmusical singing personali pact. ties I have run into for a long while. I find But in contrast to the Epic version, and in \j3~ Sound-Division her voice itself strident, uncontrolled, effec· spite of several excellent solOists, this "Car Thomson Ramo Wooldridge Inc. tive only in the low registers and at the top men" mainly featnres the glories of the Bizet little mor~ tha n a scream. Her musical in orchestra. It Is a sort of grand orchestral 555 Marion Road · Columbus 7, Ohio stincts are rudimentary and her approach nn· tone poem, with voices added. In two min subtle, if I hear right. She Sings with little utes of play you'll be aware of its potency, feeling for pu re pitch, her tones sloppily off this orchestra, even as the singers perform; Send me descriptive literature and specifications for: tune, colorless In the intonation. She appar It surrounds the singers, laps hungrily at their ently has no idea of a high note other than very feet, will not be denied--it plays up the D Carillon Stereo Tuner Model 6070 a wide·open screetch, she fumbles for notes, smallest details of scoting and phrasing for D Carillon.Stereo Amplifier Model 6060 stretches, slides . . . well, why say more. top persuasiveness--fantastic. But I can't o Bell Ster~:~ . T ape Transports Maybe I'd better go and hide, at this point. help feeling that this is, somehow, more tban All this applies in particular to t he "Lucia" the opera itself calls for. "Carmen" after all, NAME ______~~ ______recording, one of her famous roles, I gather. is not a tone poem In any sense, unless you I sampled the La Scala "Manon Lescant" prefer a voiceless version. Beecham would do ADDRESS ______briefly and got the quick impression that In tllat marvelously! this more sumptuous and elaborate music of The performance is more International in CITY ______-- --i------ZONE- ---- a later time· sbe was more at home and did style than the Epic · verSion, even though a better job. (It is early Puccini, from 1893). French musicians abound in It--soloists, or STATE ______~------Try tbat for yourself. chestra, and chorus. Bizet was accused of 52 AUDIO • MARCH, 1960 Wagnerism in this music- you can hear what was mean t in this Beecham vel'sion, so high powered is the impa ct, so vast and impnlslve you get so much more i~ the sound. Again, mighty impressive--but Is this really B izet, is it F rench ? I have some doubts. The French orchest ra itself, like most F rench ones, plays cha ra cteristically out of tune now and then and w ith the F rench-style KNIGHT® nasal t one colors, but the Beecham-inspired A PRODUCT OF ALLI ED RADIO hi-fi speakers styl e imposed upon it is not reall y French ; it is much too lush and t oo passionate, if beautifully shaped in detail. De los Angeles is an even more energetic and wobbly-voiced Carmen t han Rubio. Her d ra matic climaxes are a rresting, and Beecham's accompaniment is dazzling. T he chief tenor, Gedda, is, however, very much of an inter nationalist and not at all like the ultra French Simoneau in the EpiC version. J anine ilficheau is left to uphold the pure French way of Singing, and does it well, against pretty high odds. Net result: t hough this performance is pow erful a nd la rge-scaled, it seems to me to t a ke "Carmen" a way f rom its F rench sphere a nd blow it up to a hero ic scale that has not only too mu ch Wagner in it but also an ovel"ly big dose of latter-day Italia n opera. I can't h eJ"p feeling that t hese almost shrieking, high-ten sion climaxes, under Beecham, a re too much for t he mus ic and for t he French classic sense of propo l·tion and reserve. The performance is incomparable in the or chestral playing ; bu t as a whole, a nd in spite of its rema rkable persuaSiveness, I fi nd it not really to my taste. Even with a lack-lustre orchestra I like the Epic vers ion better. The stereo sonnd is huge fo r t he orchestra and pl aces t he s ingers mostly at a fair dis t a nce, as in t h e Angel " Lucia" l'ecording same company makes both. hig h-compliance speaker system wi,th two built-in A r t hur Janszen electrostatic tweeters Rossini: The Barber of Seville. M errill, Peters, Valle tti, Tozzi, etc., Me trop :> litan Allied's own hi·fi spea ker val ue extraordinary. Featu res patented Ope ra Chorus and arch., l e insdorf. Arthur Janszen design dual electrostatic t weeters right in the RCA Victor LSC 6143 (4) stereo cabinet-no clumsy " add-ons" needed. High com pliance woofer RCA has hit npon a very satisfactory oper atiC procedure in t his series of Met-Inspired is all-new controlled·mass desi gn. The results are phenomenal: record ings. prodnced entirely under RCA Distortion is held to a m ere O.5% at full 50 watts in put. Response direction. The best of t he RCA team are here is clean and level, 30 -2 5,000 cps. Meets the most critical pro pn t to work, a smoothly professional cast of interna tional scope, f rom Roberta Peters a nd f ession al requirements-tran sparent high frequencies beyond Robert Merdll to t he Italians l'ozzi a nd Val audible limits-smooth, honest bass. (Ask for impartial lab lett i-t hey Sing as one, blended like so much good mayonnaise under the intem a tional skill performance report.) Impedance, 8 ohms. The attractive, acous or Ge rman E ri ch Leinsdorf. t ically·sea led enclosure is hand-finished on four sides; 14 x The pe l' fo l'lllan Ce is so r emote f rom a n ac 26% x 13"; available in mahoga ny, limed oak or walnut. U.L. tual opem, at these recording sessions, t hat Approved. Unconditionally guaranteed for one full yea r. Shpg. it co nstitutes virtua lly a new musical medium -I was on hand, with others of t he press. wt., 50 Ibs . . . Only $1 29.50.$ 5 down. fo r a section of t his recording. No stage, no pit, no costumes a nd glamor ; the big ba m of a recording hall had a small stage just bi g Built-In Arthur Janszen New High-Compliance enough for t he soloists to walk on, before d esig n pa t e nte d d u a l 12" woofe r, feat u rin g three spaced st ereo m ikes ; the orchestra oc electrostati.c ra dia to rs weig hted cone in solid rat ed t he best again a nd c ast-a lumin um a ll o y cupied two widely sepa rated segmen ts of t he a gain. Bui lt·in power s up f rame .. . provides ex big fl oo r, below a t a distance and with sepa ply; certified respo nse to t re m ely SOlid. ve ry lo w rate mikes; t he ha'rpsichord and cello, fo r beyond 25,000 cps. bass p e r ~l?[ ma n ce _ accompaniment, were isolated 01'1' to one side, with more mikes. ,Mikes were everywherc dozens of them; t wo complete networks, one I5-Day Tria l & Moneyback Guarantee: Try the New Easy Terms: in tripli cate for the stereo, a n independent KN-3000 S peaker Syst e m und e r yo ur own o pe r Only $5 down set for t he mono. And the conductor waved at ing cond it io ns fo r 15 days ; if you a re not com (or less)on orders from the rear of the room, t hen tu m ed t o talk pl et ely sati sfied . yo ur purchase price will be up to $ 200. Up to via squawking "talk-back" speakers, to the refunded by Alli ed upon return of e quipme nt. 24 months to pay glass·enclosed directors a nd other function a ries. In the hall, the sound was not t hat of a nr order from conceivable operatic performance, no matter where you stood; but the multiple mikes ALLIE D R A D IO fused t he dispa rate elements into one, as bea rd bere on these records. A dizzy bu t ;~~;~~~~~~~~~~ ~ ------, highly el'l'ect ive way of doing things. 100 N. Western .Ave. , Chi cago SO, III. I RCA goes in for some calculated movement o Ship m e KN-3000 Speaker Syste m(s). : here--I saw some soloists walk as fa r as six o Ma hog. 0 Oa k. 0 Wal. I or seven feet, from a side mike t o a center $._____ e ncl. (Shipped F.D.B. Chicago) I one, during t heir Singing. As elsewhere ex for the largest selection pla ined, I find t his a doubtful procedure, o SEND FREE 1960 CATALOG. I a m inte rest ed in .saving I .o f mon e y· saving h i·fi money on eve rything in Hi-Fi. I leading more often tha n not to confusion and s peake rs a nd s pea ke r falsity in t he listening. Better a stat ic posi syst e ms (true hig h com· o Se nd impartial La b Re po rt on KN·3 000 Speake r. I tion, with quick, positive changes of loca tion plia n ce s h e lf s pea ke r I during sil ences. That, too, was used bere, and syste m s begin as low as Nam e I is the best of the resulting sound. $59.95). See hundred s I RCA sells four records here at the price of oftop buys on eve rything I Ad dress I three, in order to allow for high sound quality in Hi·Fi in the 1960 All ied througbout. A worthwhile ba rgain, decidedly. Cata log. Write for your 1E FREE copy today. L~~ ______~~_~~~ _____ J AUDIO • MARCH; 1960 53 ,,'arching beat set by drummer P ete La Roca. Rudy Vun Gelder's engineering pa irs the h Ol' ll S iu a lifelike stereo setting. Pe e Wee Erwin: Dow n By The Riv e rside United A rtists UAS6071 'l' ht'owing SODle of t he traditional conven tions to t he winds, Pee Wee Erwin arranges a set conSisting mainly of spiritnals for are· vised ed ition of his septet . Milt H inton on bass, Qsie J ohnson on drnms, Lee Blair on banjo, a nd pianist Dick Hyman doubling on organ a r e in the rhythm section. The tread is l igh ter than before, not that all dancers w ill welcome the change but listener s mlly. A dis· tinct gospel beat propels GlorylwlLd, indicating that the leader h as listened to recent develop ments, although his trumpet calls fo r th a strict New Orleans march tem po on Walk-ing With The King and The Sa·;nts. Trombonis t Lou McGarrity pays his respects to Jack T eagarden on Oa" eleBs Love, and Kenny Davern turns an occasional George L ewis CH ARLES A. ROBERTSON " pbrase on clarinet. Erwin knows t his Ill usie well enou'gh to find n ew things to say, aJld STEREOPHONIC bappen at !lIonterey, t he crowd jumped to its the rhythm men a re flexible en ough to cany feet and cheel·ecl. out his intent ions. The passages tbat Hinton Jimmy Witherspoon At Monterey The septet had warmed up during the previ and J ohn son sh a re togetber are especia lly ous set a nd two of its III mbers were due to effective ill stereo. Hifijazz J421 play featur ed roles the next day in an Ernie Carefully planned programs and the prac Wilkins composition on t he el'olution of the Count Basie: Chairman Of Th e Board tice of allowing mu icians rehearsal time have saxophone. The t hougllt of this impending Ro ulette SR52032 helped Monterey win a place at the top of the event lllay hal'e impelled Coleman Hawkins jazz festival heap-all in t h e short span of a nd Ben Web tel' to write another histor ic Count Basie : Ba sie Baseme nt two years. After neglecting the first series of chapter on the subject. Webster plays a RCA Camden CA L497 concerts, record companies made an appear magnificent, unstudied solo on Ain' t Noboll1J'$ ance at t he second and taped a fair share of Business, and Hawkins spells out his master.l· Recorded about a dozen years apart, these performances. Surprisingly enough, the initial in large letters. Ro," E ldridge gh'es a Ie son Basie items re flect ch anging times and a release ignores the principles on which Mon on open and muted trnmpet, while Wood,' co mpletely altered band personnel, except for terey's reputation is based, favoring instead I-lerman's clarinet figures we:l\'e in a nd out. t he rock·steady Freddie Greene, but are such intangibles as spontaneity and a udience Hines provides deep-toned in tro Gen tly automatic, the new GS-400 handles your treasured of the system in a moderate range, Holiday Grey changer with records with utmost care preserving the brilliance of their si lver trim, oys ter white turntable pad, original performance for many additional playings. less cartridge and base ...... only $47,50 Gently automatic, it combines the finest record playing features THIS IS THE GLASER-STEERS GS-77",,_ with all the automatic conveniences of a reco.rd changer. The World's only record changer with 'Turn GS-400 draws upon the major engineering advances developed table Pause' and 'Speedminder'-now the in the fam,ous GS-77 to provide precise tracking of stereo and distinguished companion of the GS-400. monophonic records and trouble-free operation for optimum Attractive ebony changer with brushed gold performance, trim, oyster white turntable pad. l ess cart- ridge and base ...... only $59.50 The GS-400 in your high fidelity system, brings out the best See th~ GS-400 and GS-77 at your dealer, in the other components and, at the same time, keeps the cost For details write: . GLASER·STEERS CORPORATION, 155 Oraton Street, Newark 4. N, J, A-3 GS-400 FEATURES-4-speed automatic and manual operation: J6, 33, 45, 78 rpm. rumble, wow, Hutter virtually inaudible· counter-balanced, die:cast aluminum orm • damped, acoustically isolated arm _ shock-suspension preve nts mechanical feedback thru arm pivot. Reso nance negligible • 4-po/e, hum-shielded motor - provision for 2 , 3, or 4-termina/, stereo and mono cartridges • single-knob control • double-channel muting switch, RC network lor silence on both stereo channels. AUDIO • MARCH, 1960 55 past and avoids going too far toward any extreme. The prevailing mood, set by the leader's spare, direct piano passages on The'me For Sunday, is serene and unruffied. He balan ces a trombone section on one side of the stereo picture against twenty string players on the other, ,while Milt Bernhart, Laurinda Almeida, Red Mitchell, Shelly Manne, along with other soloists are heard near the center. Pete Rugolo's setting for strings .combines the better elements of jazz and symphonic writing, attaining a full, rich sound in stereo without encroaching on the lushness of mood music. Much of the thematic material is familia r from previous recordings, but it is likely to reach a wider audience after this treatment. Ted Hecith: My Very Good Friends The Bandleaders London PS174 eLPM·70009 Glen Gray: Solo Spotlight Capitol ST1234 The last time these leaders were reviewed together here their positions were reversed and Glen Gray was saluting famous bands, while Ted Heath turned the spotlight on his / ~ personnel. But turnabout is fairplay, and it ( j will probably happen again before their careers are over. Heath's good friends are (1) Benny Goodman, Louis Armstrong, Billy May, Count Basie, Les Brown, Ray Noble, Stan Kenton, Glenn Miller, Woody Herman, Du1,e Ellington, Ray Anthony, -and Buddy Morrow. Now guess what tunes he picked to represent them. . Among the soloists featured by Gray are Mu rray McEachern, Skeets Rerfurt, Shorty Sberock, Mannie Klein, Ray Sherman, Joe Howard, Gus Bivona, and Nick FatooL Guess ing is more ' difficult this time but try any way. Both albums are meant for dancing and ~iI;$ '>' the stereo will impress wallflowers. Lambert, Hendricks, & Ross! Columbia CS8198 The John LaSalle Quartet: Potluck Capitol ST1238 SPHERIC N" After making a series of recordings with the support of various assemblages, includ MODEL T202 SUPER TWEETER ing the Basie band, L ambert, Hendricks and Ross are heard here under a new contract and in the com pany of the I ke ,Isaacs Trio, a g roup which has grown accustomed to their intricate vocal juggling as a regular part of Apparatus patent pending on acoustical action of baU. cone the act prepared for jazz clubs. Harry Edison, ...with frequency response and diaphragm. Design who supplies muted trumpet obbligntos as patent pending. an invited guest, is a lso no stranger, having served b.efore as both an accompanist and an to the supersonic example to imitate. The performance is . bl'ough t to n higher degree of polish than any previous one, as a result, a nd the voices range of 40,000 cps ••• sound much less crowded in t he dimensions of stereo. The group claims an active reper :!: 2 db to 22,000 cps! toire of seventy numbers, by recent count, 2.noo ] 4 567 891D.GOO 202223 24 2S 30 40,000 which is no small achievement when the de JIAi~llllfllllllllFR[QU[HtY1N tYClESP(R SECOHD Hmands of the various styles and material are considered. Among the tunes translated from instrumental originals are Bobby Timmons' COMPARE THE SPHERICON WITH ANY OTHER TWEETER Moanin', Ralph Burns' Bijou, Horace Hender sons' Cha,-leston Alley, the Addel'ley's Ser monette, and the Miles Davis·Gil Evans read , .. at three or even four times its price! Whether you wish to add thrilling ing of Suut1nertVnte_ Annie Ross revives her Bring your own r ecord (one you know brilliance with musical warmth to your rersion of Wardell Gray's Twisted, Edison really well) to your University dealer, present system, or to the system you're solos on his own Cen.terpiece, and Hendricks adds two originals. and learn what you've been missing up now planning, you'll find that nothing The John LaSalle Quartet also enjoys the to now. compares with the University Sphericon! distinction of being able to intrigue the adult, For the first time you'll hear the com sophisticated listener and affords a pleasant plete high frequency range, and with SPECIFICATIONS: Model T202 con trast to the Lamberts. Organized to fill Dispersion: 120· in all directions. Power capacity: an engagement at Dick Kollmar's Left Bank the clarity, transparency and sweetness 30 Vo[a tts integrated program. Impedance: 8 ohms in Manhattan, the group was introduced on you never thought possible. nominal (may be used with any 4·16 ohm speaker). an excellent debut Lp titled "Jump;n' At The entil'ely new concept of this direct Design features: domed phenolic diaphragm, conoidal '7'h e Left" Ban k." At t he start , its style bore ring loading. spherical diffractor. Cro'ssover: 3000 cps. ·the trademark of updated swing, but now is radiator tweeter, with its special domed Sensitivity: 93 dba at 4 ft. with 1 watt input. Mounting: broad enough to encompass A la Cal;,-e Fon phenolic diaphragm and spherical dif front or rear surface of baffleboard. Dimensions: 40/8" diameter, 4" depth $24 ta';,ne, and an a capella Christopher Robin 18 fractor, results in a virtually linear re over-all. PRICE: with built-in network 95- Saying His Prayers. The leader a nd Marlene sponse-with tt'Ue musical quality':"'far Ver Planck are soloists, while Bill Ver P lancl! ,,' " ... "." """"iIi'''''··· '::: contributes arrangements and the title tune. superior to even the finest of electrostatic His practice of voiCing a ha rp or flute on tweeters. ballads and the sound of a full band: on And unlike the electrostatic tweeter, swing items is splendidly' realized in stereo. the highly efficient Sphericon can be per BYCHO/C~OR CHOICE fectly mat<;,hed to any system .. . especial Johny Puleo: Western Songs ly high compliance ... without sacrificing UNIVERSITY LOUDSPEAKERS, INC., WHITE PLAINS, N. Y. Audio Fidelity AFSD5919 'Fhs constant companion of cowboys and bass efficiency, A 8ubsidia,'Y of L inu-Altec Electronics, Inc. loners everywhere is the harmonica. Johnny 56 AUDIO e MARCH, 1960 Puleo prefers to call it a mou th organ and takes a ll the old f ami! ia r gang a long to l,eep him co mpany while riding t he range. H e slJl·eads fo urteen Western songs out in s ter eo, riding herd on s uch g rassrooted t unes as in tune with any setting W('gon W hee ls, T",nbling Ttw,bleweeds, San Ant onio Rose, a nd R ed R iver V alley. When The new Madison Fielding Series 630 FM Tuner is t il e tempo becomes too briSk, h e turns t il ~ stampeding h erd with a mour nful balla d, even equally at home with the most basic or complex r eso r ting to When YO t ... 1I(,';r lIas Tl£n,ed component syst ems. This highly sensitive unit has 'j'o Save' ·. Wa tching him·in action could well been des igned wi th matchless en ginee ring excel lead to the belief th at a lasso is n eeded in tbe studio to keep him still long enough to r e lence , yet it sells at an unheard of $84.95. cord. Whatever the methods used, his w a n dering ways a re curbed in stereo a nd move The 630 is t he most tunable tuner in hi-fi history. ment occurs only wil en t he solo voice is tossed A new concept in tuning el iminates the moving f rom One instrument to a noth er. pointer. Th ere's no need to look f rom selector dia l to tuning indicator. Just fix your gaze on the verti The Limeliters Elektra EKS7180 ca l tu ni ng eye as t he stations gl ide across t his The Kingston Trio: Here W e Go Again point. Li st ening flexibility is greatly enhanced by Capitol S11258 dial-varia ble amplified AFC which permit s drift Sun F l'uncisco's li t he hungr y i," wher e t he f ree recepti on of the weak stations most tuners Kingston Trio fi rst hit t h e t ra il to fame a nrl fortun e, sends a long a new gr oup which seems generally reject. Another unique f eature is the re destined to follow the same h eady byway. movable t op pl ate to facilitate multiplex adapter Orga n ized less t ha n a year ago, t h e Lime installation. liters were h eld over a t th e club for five mon ths, appeared on n etwork t elevision a nd The unit, with brass and black finish ed heavy readied this debnt LP. Aba ndoned somewhere a long the rou te was the proposed title "Folk aluminum front panel, is housed in a striking, Songs for Moderns," a nd th e album is being black, vinyl cl ad enclosure. Write f or compl et e promoted for its popula r appeal. The t rio, specif ications. formed after t he chance meeting of singers successful as single acts, u nites Alex Hassilev a nd Glenn Yarbrough under t he leadership of Lou is Gottlieb, a worldly gentleman wh ose Ph.D. in musicology fails to con ceal a Imowl m .. d'.Of> U.''''''11 edge of jazz and the string bass. Sever al of .. t.u .. IlltHHU\ .. , his a r rangemen ts a r e the property of the Kingston boys a nd h e performs t h e same dut ies on a broq,de r scale h er e, writing hilari ous versions of The Midnight Maral£de,·, a nd Gad , Gar i. The h umor is sophisticated w ith out be ing too far ou t, an d th e satire is sh a r p bu t friendly. T he g roup refra ins from wor )\ ing anyone vein to exha us tion, quieting tlH~ customers w ith Yarbrough's ear nest tenor lead on When I Fi' ·st Gmne To 'j'his L mul. ASS i sting at assjgnea intervals from variou s poin ts on the ster eo spectrum are J Oh l1 Pisall o, Charles B erghofer, Gene Estes, F rank De\'enpo rt, a n d Vincen t T er r i. No need for the Kingstons to bid for POP Il la r approval-th ey have it, and to sparc. After citing their present effor t as t h e best yet, it migh t be rema r ked in passing t h a t two t unes are by t h e aforemen tioned' Gottlieh. Bla me h im fo r a ny de via t ion f rom th e stmigh t ethn ic path. Leon Berry: Giant Wurlitzer Pip e O r gan, Vol. 6 Audio Fidelity AFSD5904 Although labeled as Leon Berry's sixth appearance ·at th e giant W urlitzer , some vol umes in t he series in volve th e smaller instr u ment installed in t he basement of his h ome. The organ heard · her e, h owever, is easily r ec ognized as the t hree-m a nual beh emoth h a r bor ed in Ch icago's H ub Skating Rink. The n umerous color effect s are broader and, t o a llow for a gr eater r e\'erberation t ime, t h e tempos are slower. Its . si ze is fully ca pable of accommodating 76 T r orn bones, a ncl the sunny panorama of. Me'l'ican D ance. Among old favorites r ecalled a re Ida, A t Sundown, F,·encs:i, a nd that sluiter's delight, L ich ten steiner PoU,a. As bef ore, the r ecording af fords a stiff t est of bo th equipmen t a n d stereo techniq\les. ConSidering t he n ature of the mammoth, which permits n o t ime-stretch in g devices, t he eighteen-minute playing t im e on each side is excellen t, and the sound leaves li ttle to be desired. O scar Brand: Every Inch A Sailor Elektra EKS7169 Seemingly bent on document ing the p resent day folklore of t his n ation 's Armed ForceH, Oscar Bra nd follows up h is collection of Air Force songs with one f roUl th e Navy a nd h as a set of Ma rine ba lla ds r eady t o sail in its wa ke. Some mont h s wer e spent in r esear ch be Illad ison f!o~!g!s~g fo re the singer decid ed on' relia ble, rath er th un strictly "a u thentic," ver s ions of fou rteen BRAND PRODUCTS INC. lusty and salt-stained t unes. Along with t h.e DEPT A-3, 39 WEST 55 STREET, NEW YORK 19, N. Y; native attractions o( Giiant(, na1llo B ay, a base Natio n al ma r ket i ng o rga n ization fo r M ad ison F ie l ~ i ':'t ._. cu rrently in the h eadlines, scenes- of World AUDIO • MARCH: 1960 57 War II are revisited on Reuben James, anu Orleans styles. On Rinehar t & Company's cur Battle of O"moc Bay. Jus t how new a r e the rent list, his book about these colorful person for less 'W or k and m 01'e play verses selected for Banwc!e Bill, Zamboanga, alities is full of interesting detail on the meth and Didn't She Ramble wiII depend largely ods of early recording companies. upon the listener's own age and experience. GET THE TURNTABLE If a young inductee is numbered among your Benny Golson: Groovin' Wi th Golson acquaintances, he w ill find this an ideal ste;:> toward developing sea legs. Brand's assisting New Jazz 8220 THAT CHANGES RECORDS! yeomen, distributed about t he deck in stereo, Before Art Farmer joined the group, Benny are Billy FD.ier, Mike Seeger, Milt Okun, Rus Golson worked with trombonist Curtis Fuller, sell Sa val 58 AUDIO • MARCH, 1960 Tucked a way somewhere in a stack of old a rchives at last, making the assembled nug Rhythm Jlian, And finally, an ins pired .iam jazz mn gaziues fire my programs from these get s availnble to all. 'L'hey assay high on the session mounts gradually in intensity to eli two co ncerts. with the cOver of the first bear basis of today's ma rl;et and are s ure to enrich m,U ic exchanges be tW een bassists Walter Pare ing the smiling featnres of Bessie Smith, for any collection . While confirming m,' impres a nd Arthul' Bernstein. the great blues Singer had died just the year sion of two wonderful Christmas holillay eve The acetate masters were made by Zeke before a nd the evening was dedicated to her nings, the editing mal;es no attempt to adhere Frank, who a short time before h ad used the memory. Other tangible memen tos were to to the origin a l order of even ts. Anyone who sl1me single overhead microphone to record result from the ben efi cial effect a Carnegie wants to aSSign a performance to t he proper Benny Goodman's first Ca rnegie Hall appear Hall appearance h nd on the r ecording careers year can do so by refel'l'ing to the thorough ance, which Columbia was to issue even tua]] y of S idney Bechet, Sonny T erry, Big Bill notes. Besides featuring the Benny Goodman on LP witb such outstanding su ccess. Let's Broonzy, Ruby Smith, J oe Turner, a nd the Sextet, the second concer t brought bacl, the h ope th e sales of this set are as good, because boogie-woogie piano team of Pete Johnson , Kansas City S ix from Coun t Basie's ba nd and Hammond has enough material left over for Albert Ammons, and Meade Lux Lewis. Some the splendid work of these g roups is promi another three L P sides. The improved tech were unknown before stepping on the stage, nen tIy displayed. At th e peak of his powers, niques available today have enabled Seymour while the depression had forced oth ers into Lester Young can be heard developing his Solomon a nd John Beaumont to produce a making a li ving away f rom music, and the characteristic long lines on tenor sax, wh iJe superior processed sound, a lthough it is pos helpin g hand of J ohn Hammond arrived at an Cha rlie Christian sits in on Good Morn.'Il,V sible to tell H ammond's favorites from t he opportune moment. As the show's producer, Bllles. Those who remember Christian only for varying amoun t of wear on the aceta tes. Per he gathered per fo rmers from a ll over the his single-string guitar solos should listen to h aps he will be encouraged to embark on an country and then was drafted into active par him operate with Freddie Green, who is still other series of concerts. Earl Hiues is ou the ticipation as master of cer emonies. On the Basie's rhythmic standby. road again, a nd Lightnin' Hopkins, Jesse heels of this bold a dventure came his appoint Other highligh ts are two piano solos from Fuller, Snooks Eaglin, a nd Jimmy Wither ment as associa te recording director for Co J ames P. J ohnson, and Sidney Bech et leading spoon h ave yet to set foot on a New York lumbia Records, a post which enabled him to his New Orleans Footwarmers, with Tommy stage. The aftermath might be equally re",aru Ladnier playing trumpet, on Wea,'y Blues. ing as h e has returned to an a r t ists and rep engage many of t he same a r tists again. Other Ida Cox shouts a blues over the support of ertoire pOSition at Columbia. That company is companies followed suit, while the Solo Art Buck Clayton and D ickie Wells. Mitchell's stepping u p jazz releases to It eep pace with and Blue Note la bels were founded for the Christian Singers anll the Golden Gate Quar an expanding record club, but Hammond will express purpose of recording what the com tet document gospel Singing during t hat period maintain his ties with Vanguard also. Co me l'cial firms were likely to miss. of its development. 0 1'an Page, whose trumpet lumbia is reported to be planning an a mbitious On this two-disc set, a goodly portion of is too sparingly represented on LP, joins t he jazz reissue series, starting with Fletcher both concerts is eXhumed from the H a mmond full Basie band on Blues With LipS a nd Henderson and Mildred Bailey. 1E The same material cannot properly be a rigid cone and a compliant suspension. In all KLH speakers, cone and suspension are separate parts, It~t!.I1*tl Research and Development Corp. Here the suspension is being formed, Cambridge, Massachusetts by hand, of liquid butyl rubber. A KLH cone is rigid. Its suspension, 'is. : compliant. AUDIO • MARCH, 1960 59 . ~ . .. -. SAVE HAROLD LAWRENCP 25% High Fidelity-Enemy or Friend of Live Music? F' ONE were asked to single out the most .formed audiofan wince. Under the best important development in the audio field possible circumstances, esthetics and engi ::"! I during the 'Fifties, the answer might be neering are uneasy partners either in the the emergence of high fidelity as a mass t ask of recording a musical work, or in This is our market , commodity. The industry has come expressing an audio-musical idea. The audio a long way since the days when record literature of the 'Fifties abounds in articles GROUP SUBSCRIPTION PLAN buyers were urged to purchase 33%-rpm containing half-digested engineering con attachments which could be plugged into cepts, written by non-technical writers who Now you, your friends and co-workers the table radio. Component manufacturers would dearly love to give us all the im can save $ 1.00 on each subscription who had once sold their products only to pression that they are intimately familiar to AUDIO. If you sen.d 6 or more sub with the underbelly of an amplifier or the scriptions for the U.S., Possessions and professional sound engineers, and a handful Canada, they will cost each subscriber of enlighteI\ed audiofans, now discovered dI"ive mechanism of a tape r ecorder. On the other hand, some writers are $3.00 each, Y4 les ~.-than ' the regular that the gener-al public could he weaned one year subscriptf~ i> ..p'r ice. Present from ready-to-play merchandise. Accord equally determined to have no truck with subscriptions may be.. ..renewed or ex ingly, they expanded their trade advertis the mechanics of sound reproduction which, tended as part of a Woup. Remittance ing and eventually bought space in na according to Virgil Thomson, "give [music] to accompany orders. . tional, non-technical magazines. N ewspa pers a slight flavor of canned food." Mr. Thom and FM broadcasts, too, provided effective son's reference was to processed music of AUDIO is still the only publication means of reaching th~ potential audio fan. the early 'Forties, but I would venture to In the same · decade, the record industry guess that his opinion has not altered devoted entirely to rose to new sales peaks, and the audic.> sho:w basically sin~ then, despite the remarkable ,-. became au annual affair in a number of' audio advances to date; 'his only concession' • Audio might be to change the word, "canned," to • Broadcastin g equipment cities. It is interesting to note here that "packaged high fidelity" was specifically "frozen." Thomson's remark appeared in an • Acoustics barred from participation in some of the article printed in the New York H erald • Home music systems major shows. Before the decade was out, Tribune on May 16, 1943. In a certain • Recording the term high fidelity belonged not to the sense, it graphically illustrates the progress • PA systems few, but to everyone. Once in the public of high fidelity sound reproduction over the • Record Revues domain, however, it was soon transformed past seventeen years: "The easily notice (Please print) into the slicker and shorter hi-fi. In the able differences between fresh and proc process, the concept of high fidelity fell by essed music are several. Deformation of Name ...... the waystde. For example: "Dear, please instr111J.lental timbres i~ not the gravest of Address ' .'. . : ~-•...... '... . tum down' 'the hi-fi'." (The wife refers, of these. . . . Diminution of the original dynamic range is a far greater musical •••• •••• ••• •• ~~f • •••• •• •• •• •• •• •• •• course, to her mate's sound system.) o New ...... : 0 Renewal . ....•.. To the best of my knowledge, English distortion. The limits between loud and men never say, "the hi-fi"; they call their soft at any given tuning are so much Name ...... •. equipment either by the old-fashioned narrower than the dynamic range of a full Address ...... ,., ...... ; ...... • "gramophone," or by th'e newer "rig." But orchestra, or even of a singer or of a piano the term, high fidelity, is as popular there forte." as it is in all other audio-conscious natiol'ls. The microphones and tape recorders of New ...... D·Renewal ; ...... o In their two-man hit show, At the Drop of today enable us to keep distortion down to Name ...... : ...... a Hat, the Britons, Michael Flanders and the barest minimum, while ' the dynamic range has been vastly increased -though Address ...... : ...... Donald Swann, sing a song abont an andio enthusiast whose total preoccupation with not yet as full as the 95 db output of a his rig drove his frustrated wife into a large orchestra. Time, however, has not af o New ...... 0 Reni',,(al, . < ••• ••• state of "low fidelity with high frequelj.cy." fected Thomson's comparison of processed The popnlarity of "hi-ti," however, far out and fresh music from another standpoint: ~ : /, : :'>.~~: . :::::::: weighs its verbal predecessor. A couple of " [The former] may occasionally be prefer :=::5; :::: :::: ,t '. years ago, for instance, a leading manufac able to fresh [music]; but it does not ...... _ .. - .. . - . . , - - " ' -" ...... ; .. turer of cosmetics borrowed the term from sound like fresh music, and one's relation o New ... , .... ,' 0 Renewal , .. ... ;... , the audio industry to launch a ~ew line of to it is that of a listener to a live execu lipsticks. tanto It is like a photograph of somebody Name ...... -that is to say, more or less resembling. Address ., ...... The High Fidelity Writer But there is no communication between the observer and the subject of the picture." o New ...... ".. 0 Renewal ...... The impact of high fidelity on the na tional scene produced an apparently end Copies and Originals Name ...... , ...... less flow of articles on the technical, musi The record-photograph analogy was em Address ...... cal and philosophical implications of sound reproduction. It was not unusual to leaf ployed more recently in an essay on live vs. through a magazine specializing in food or recorded music appearing in the J anuary o New ...... 0 Renewal ...... travel and come across an article on "What issue of Harper's. The author, Hubert U. S., Possessions, and Canada only is High F idelity ' " Some were written by L amb, bemoans what he calls the Age of competent authors who were recognized in Facsimile. The music facsimile, he writes, RADIO MAGAZINES, INC. their own fields, but many were of the "[is] a product of the exercise of the dis pseudo-technical variety that make the in- cretion of monitors and the skill of editors, P. O. Box 629, Mineola, N. Y. is a composite image of performances con * 26 W. Ninth St., New York 11, N. Y. ducted in the vacancy of an empty hall. It 60 AUDIO • MARCH, 1960 is necessarily without _serious blemish. The maker of facsimiles, like the fashion pho tographer, must concern himself first not with poetry but with perfection." With DYNAKIT you know you have the BEST! In his three-pronged attack on music re The finest high fidelity you can buy at any price cording, Mr. Lamb implies the following: 1), tape editing somehow destroys the in tegrity of a performance; 2), the absence DESICN ED FOR STEREO of an audience makes for listless results; and 3), the recording man is more inter ested in notes than music. I should like to review these points one by one. First, the skillful ta'pe_edito r selects the best played 'takes' of the session for his master reel, but he does not put them to gether willy-nilly _on the sole basis of note perfection. Tempo, balance of instrumental choirs, - continuity, intensity, and over-all PAS-2 $59.95 feeling are some of the factors which he must take into consideration before making • New stereo control preamp w ith complete flexi bility, fastest construction, and simplest operation each splice. He must possess keen ears,. and • Two outstanding 35 watt channels (160 watts he must be meticulous bnt not Beckmesser peak) to power any speaker. Less than .5% • All long lift components. 1 % parts used in distortion at rated power ish. Second, the lack of an audience is ad critical circuits mittedly a difficult hurdle to overcome at a • Unequalled transient response - excellent square .' session. But with a dedicated conductor at • 2 pre-a s'sembled heavy duty printed cir,uit wave performanc.e __ the helm, there is every r eason why a boards make construction simple and bug-free • Absolute stpbility with every loud-speaker w ith recorded performance can be every bit as out restriction of band-width good as its concert equivalent from the • Truly unmea surable distortion - below 0.05%. • Smooth and crystal clear sound with superb Lo west poss ible n,oise. delineation of heavy passages point of view of the musicians' spirit and attitudes. It is the recording diI'ector's job, too, to smooth the way for truly musical STEREO I N EASY STEPS results in his pacing of r est periods, re takes, and musical .movements. Third, for Start with a superb monophonic system obvious reasons, note perfection is .a desir· able objective in a recording. But the re cording director's principal goal is to help make it possible for the "poetry" to emerge while at the same time keeping an ear out for accidents, lost notes, and faulty musical balance. Later in his article, Mr. Lamb goes even further on the subject of music vs. records. A recording of Mozart's Symphony No. 41, "is not the Jupiter Symphony. It only sounds like the Jupiter Symphony. The players are not there. There is, in fact, no • Hi story-making "no-distortion" preamplifier performance. We are therefore not partici which has never been equalled • Either the renowned 60 watt Mark III or its new little brother, the 40 watt Mark IV pants in anything; and unless our experi • All feedback design and close tolerance parts ence with music itself intrudes, we may result in lowest noise, lowest distortion and • 3 hours to build converse, play our games of chess, and read fin est sound our newspapers, quite unconcerned, taking • A quality of performance unexcelled at any note or not, as we will, of the engaging • 6 hour assembly price fabrics of sound with which we have sur· rounded ourselves." Expand to matchless Stereo Mr. Lamb is plainly flaying a dead horse. Certain exuberant advertising copy to one side, no one seriously expects a phonograph disc to magically transform the grill cloth of your loudspeakers into living musicians; nor does one look forward to a live concert hall experience. A recording is- simply a musical document shorn of the accouter ments of the conced hall; that is,- without the full acoustics of the auditorium, the sound of the actual instruments, or the • Every stereo function at your fingertips thrill of mass participation. Nevertheless, including Dyna Blend control . • Just add a second Mark III or Mark IV and if one is not playing chess, reading news· • Un surpassed fl exibility you have the most recommended, most de papers, or conversing, but is listening in sired stereo amplifier ensemble • Unitized panel or cabinet mount available as tently to a recording of, say, Boris Christoff an accessory • Dynakits provide the finest in high fidelity singing Moussorgsky songs, one would have to be quite insensitive to escape the drama and beauty of the music-yes, and even of the performance. See and hear Dynakits at your local dealer Probably the most extravagant state ment ' in Mr. L amb's article occurs at the A post card will.bring complete specifications conclusion. Seeing nothing but danger ahead for the state 9f music if the current popularity·of recorded music continues, the DYNACO, INC., 3916 POWELTON AVENUE, PHILA. 4, PA. CABLE ADDRESS : DYNACO, PHILA. (Continued on page 71) ,AUDIO • MARCH, 1960 61 NEW PRODUCTS • Battery-Powe'red High-FideUty Tape • Ampe,x Amplifie-r-Speaker Systems. Am transformer, and may be use d with any Recorder. Despite its light weight and pex h as recently introduced two unique load resistance from 47,000 to 100,000 self-powered feature, the B utoba MT-4 is a mplifie r-speaker systems based on the ohms. Optimum loading is 68,000 ohms. Stylus replacement can be handle d by the stated to have a frequency response of 50 system-engineered concept, wher e in each user in a matter of seconds. E ach replace to 13,000 cps with less than 0,5 per cent sepa r ate element was d esigned not as an ment stylus comes mounted with its own flutter at 3% ips; it will also operate at individual component, but as an integral, damping blocks, thus assuring a penna 1 % ips for extended play. It is equipped properly matched unit within the system. nent high level of performance. Frequen cy with separate volume, freble, and b a ss con The new· Model 303 system, illustra t ed, response is v irtua lly flat from 50 to trols, and uses 5-in. ree ls with maximum makes available in component form the 18,000 cps. Stylus pressure r equired is 3 same impressive sound offered by the Am pex Signature home music system console. The units are identical with those used in the Signature models, and within a com parable e nclosure will produce sound of identical quality. The system contains an recording time of three hours. In a ddition to operating on interna l flashlight cells, the r ecorder may b e operated on any inter mediate a.c. voltage between 110 a nd 260, a nd from a car b a ttery with the use of a converter which is available as an acces sory. It may be operated in a ny position Ampex 30-watt a mplifier, a multiple L /C crossover n etwork, a 3-in. tweeter, an 8-in. except upside down. Unusual technical re to 5 grams. Effectively shielded by mu finements include t h e motor speed being mid-range speaker, and a 15-in. woofer. metal throughout, the influence Of. exter kept constant within 1.0 per cent regard Two such systems are n ecessary for na l magnetic fields on the cartridge IS less of the life of the batteries, by means stereo. Operating characteristics are flat negligible. For f urther information, write of d evoting the entire function of a tran w ithin 0.1 db throughout the maximum North American Philips Company, Inc., range of hearing a bility, at rated output. H igh Fidelity Products Division, 230 Duffy sistor to speed regulation, over a nd ab'ove Ave., Hicl{sville, N. Y. C-5 a regular motor speed regulator. Motors Total harmonic distortion is less than 0.5 are protected by twin fuses. Other features per cent at rated output and noise level is • Portable Tape Recorder. Fully transis of the MT-4 include fast forward and re down 80 db. The Model 302 system is iden torized, this n ew two-speed book-s ize tape wind, push-button controls, recording-level tical with the a mplifier-speak er assembly recorder weighs u nder four p ounds and indicator, time indicator, and completely e nginee r ed for the Ampex Custom series operates from its own s e lf-contained bat climate-proofed dynamic microphone. Bu home music system. The amplifier power teries, 117 volts a .c. or from the cigarette toba Division, Turning Corporation of rating is 15 watts. A 3-in. tweeter and lighte r receptable of a car. Known as the 12-in. woofer make up the speaker system, Concertone Tra nsicorder, it utilizes a America, 60 E. 42nd St" New York 17, N. Y. comple m e nt of six tra nsistors a nd two C-1 which requires a 2-cu .-ft. enclos ure. Char diodes. It h as a one-hour recording ca acteristics, except for power rating, are pacity. A dual-function meter serves to • E.M.I. " Ste,re.oscope" An~plifie-r. Preci virtually identical with those of the 303. m onitor recording level as well as to sion m atching of stereo sound channels Ampex Audio, Inc., 10 20 Kifer R oad, Sunny check battery condition. Operating s peeds is accomplished by m ean s of a cathode vale, Calif. C-3 a re 3 'li. a nd 1 % ips. Two heads are in ray indicator tube in the Mode l 555 am corporated, one each for record/ playback plifier recently introduced into the United • Heathkit Multiplex Adapte'r. This in and for e rase. Accessories for the Transi States by Electrical & Musical Industries, strument is the n ewest a ddition to the corder include h a nd- a nd foot-operated Ltd., Hayes, Middlesex, Eng. Inte nded to Heathkit line of high fidelity equipment. r emote controls, telephone pick-Up, stetho increase the ease and accuracy of both Designated Model MX-1, it is designe d to type earphon e holder, and a dapters for stereo a nd monophonic a djustments, trac permit reception of FM stereo programs 12-volt d.c. and 117-volt a.c. power sup- ings on the face of the tube may be used transmitted in accordance with the Crosby to measure signal strength, check fre system of stereo broadcasting. Among its quency response, monitor input or output voltages, a nd maintain a continuing check of the performance of turntables, pickups, and other system components. Consisting of twin preamplifiers and two' independent 20-peak-watt power amplifiers on a single features a re a seif-contained power sup ply, stereo-dimension control, channel balance control, f unction selector switch, inputs for FM (ma in channel) and multi plex (sub-ch annel) and cathode-follower chassis, the 555 is the first unit in a new outputs for both c hannels. The function line of high fidelity components being switch provides for stereo, main channel, introduced into the U. S. by E,M.I. A pre or mUltiplex channel mode of operation . plies. D evelope d particularly for those cision amplifier in every respect, it meets Heath Company, Benton H a rbor, Mich. 0-4 demanding good quality s0U11d r eproduc or exceeds professional standards in a ll tion combined with portability, the re areas of a udio performance. When desired • Norelco Stereo cartridge. Featuring the corder can be carried with a shoulder the 555 may be used as two separate unique combination of exceptionally high strap for in-fleld interviews, laid on the monophonic amplifiers. A separate 7-posi vertical compliance and high output, the seat of a car for dictating while driving, t ion function switch is a fforded for each Model AG3400 cartridge will play a stereo or used in an office or home. It u ses channe l. . A front panel switch may be record innumerable times without loss of standard reels, batteries and tape, and used for injeding a GO-cps sinusoidal quality, at the same time eliminatin g hum records half- track. American Concertone voltage into the preamp section which and noise generated by amplifiers forced Division, American Electronics, Inc., 9449 m ay be used for balancing purposes. Dis to operate at maximum gain. Vertical com W. Jeffe rson Blvd., Culver City, Calif. C-6 tribution rights for E.M.I. high-fidelity pliance is better than 3.5 x 10'" cm/dyne, components in the United States have lateral complia n ce is 4.5 x 10'" cm/ dyne, • Magnetic Recording Ta.pe-. A deluxe re been assigned to Scope E lectronics Corpo and output is 30 mv per channel. Channel cording tape, accomp a nied by a unique ration, 10 Columbus Circle, New York 19, separation is 22 db at 1000 cps. The g uarantee, has recently been introduced New York. 0 -2 cartridge does not require a matching by the Triton T ape Company, Woodside, 62 AUDIO • MARCH , 1960 . ' N. Y., t o m eet the dema nds of discerning 3 NEW' rrUNERS FROM r ecordist s , both a mateur a nd pr ofessiona l. The g ua ra ntee promises the Triton t a pe purchaser a r eplacem ent r eel of a ny America n-ma de brand of the sam e t y pe s hould h e find the Triton defi cient in per forma nce or ch a r acteris t ics for "any ..~ H.H. SOOTT magnetic recording tape Stereo reas on w hatsoever, or in a ny way n ot as AM-FMTuner represent ed." Triton t a pe is process ed $ 239.95* w ith an exclus ive "Trionizing " t echnique, w hich in cor por ates three essentia l tape production processes in sequen ce, assu ring a prod uct of high q ua lity a nd r eproduc t ion capabilities. All Triton t a pe is splice free, wou nd on n on-warp, n on -squeal r eels, a nd includes a h eavy-duty My la r leader a t both en ds t o f acilitiate a nd p r otect Wide-Band FM ...Wide-Range AM Make These labeling of r ecor dings . A tape r et ain er clip is s upplied f or holdin g the t a p e tigh t on t h e reel. F or det a ils , con tact Bran d World's Most Sensitive, Most Selective Tuners! P roducts, Inc., 39 W . 55th St., New York 19, New York. C-7 The completely separate PM section of the radically new H. H. Scott 330D • Dyna-Twin. Headset. This new h eadset stereo tuner utilizes H. H. Scott's exclusive Wide-Band PM circuitry to assure recently introduced by T elex is intended absolutely drift-free and interference-free reception in even the weakest signal essen tially for private listen in g t o s t er eo program material. The twin wide-ran ge areas. Wide-Band design also lets you separate stations so close together on dy na mic receiver s h a v e a f requen cy range of 50 to 15,000 cp s. They a r e engineered the dial that ordinary tuners would pass them by. The separate AM section utilizes H. H. Scott's unique Wide-Range detector so that, for the first time, you can receive full range AM broadcasts with fidelity and frequency response comparable to PM. SpeCial multiplex adaptor facilities let you· convert to multiplex at any time. 320 AM-FM TUNER The many fine fea tures built into this superlative tuner,. including Wide Range AM and Wide-Ba nd FM, have never been available before for less than $20Q. This tuner is ideal where AM-FM stereo reception is not available. $159.95 * 310e FM TUNER This professional tuner is the most sensitive and selec tive available. Its outstanding per formance and sensitivity have made it the choice of universities and laboratories throughout the s pecifically for headset application a nd world. Sensitivity 1.5 /.LV for 20 db of quieting. are equipped with t w o com fortable ear (IHFM rating 2 j1.v) $184.95 * muff-t ype ear p h ones. Cons truction of · SJightly higher West of Rockies. Accessory case extra, stainless s t eel, T eflon a nd Neopren e as s ures m aximum protection from da m a g e. The Dyna -Tw in comes complet e with 8- ft. fl exible cord a nd 3-contact plug or two sta n dard phon e plugs. It can be u sed either bin a u rally or m ona ura lly . Ma nufac ... ~ H.H.SCOTT ..... t ured by T elex, Inc., SL P a ul, Minn. C-8 H.H. Scott, Inc. 111 Powdermill Road, Dept. A~3. Maynard, Mas s. • DynaJdt stereo Prea.m.p1i1ler. Availa ble Rush me new catalog and complete technical spe· in both wired and k it form, the new Dyna kit Model PAS-2 is a deluxe s t ereo con cifications on all new H. H. Scott components. trol unit which f eatures unusua l v er satil ity and fl exibility along with exceptionally Name ...... low distortion a nd n oise. Although a s m any as s even stereo, or fourteen mono Address •••••.•••••.•..•.••.•••.•••••••••••, phonic, inputs ca n b e utilized, the PAS-2 is simple in operation a nd uncomplicated City •...... •.•••.•...... • State •••••••••• , in a ppeara nce. Construction of the instru m ent from the kit is g r eatly simplified Export: Telesco International, 36 W. 40th st., N.Y.C. by the use of two f actory-ass embled printed-circuit b oards which include about INTEGRATED STEREO ARM AND CARTRIDGE' AUDIO • MARCH,· 1960 three-quarters of the components. Ave,' Dyn~co, Inc., 39 16 Powelton Ave., Phila on either side of the listening a rea (and age cons truction time is ·a pproxima t ely delph,a 4, Pa. C-9 closer to it tha n the m a in speakers) , the eight h ours. The built-in power supply a u gmented stereo sound pattern will be enables operation with any power a mpli • Fisher Speaker System. The new WS-1 h eard not merely a s a straight-line cur fier. Frequency response of the PAS-2 "Wide-Surround" speak er system offers tain of sound, but 'curved,' totally sur stereo console a nd component owners rounding the listener." Although the WS-l r eproduces only the middle and high fre quencies, 250 to 15,000 cps, the non-di rectiona l character of low frequ encies permits the illus ion tha t the WS-1 is repro ducing bass tones as well. On late model Fishe r consoles-there is a special WS-l output. Fisher R a dio Corporation, 21-21 44th Drive, Long'Isla nd City I, N. Y. ColO • Stereo Test Tone Genera.tor. This device, which is called the Twin Tone a nd is com pletely transistorized, permits b a la ncing the output of stereo speakers iIi a matter of seconds. It is simply plugged into unused inputs of a stereo a mplifier and Is is 10 to 40,000 c ps ± 0.5 db, a nd intermodu lation is below 0.05 per cent at s uffi c.i en t o utput t o drive a n aver age a nlplifier. Equa lization characteristics are closely distinct a dvantages in that it greatly controlled through the use of 1-per-cent enhances the stereo effect of conven toler a n cp. comoonents in the critical n et tiona l s peak er arrangements. According works. Full details are a va ilable from t o Fisher engineers, "by placing a WS-1 ready for immediate u se. By s liding a sw'itch located on t h e front panel, a con stant 1000-cps tone is · produced. The vol ume controls on the a rriplifier a r e then a d justed until t he speak ers have identical output. A volume control permits adjust ing t h e signal to any desired level. The Twin T one is powered by an intern a l mer cury battery. Kinematix, Inc., 1616 N. Damen Ave., Chicago 47, Ill. C-lI NEW LITERATURE • Allied Radio - "Corp., 100 N. Western Ave:, Chicago 80, Ill., a nnounces the re lease of a n ew 36-page booklet entitled "This is Stereo High-Fidelity." Prepared by the publica tions staff of Allied, with t he editoria l assista nce of Edward T a tna ll Canby, columnist a nd chief r ecord r e viewer for AUDlO, this easy-to-understand booklet is a highly informative guide for a nyone who wants the facts on stereo. Written in straightforward, non-technica l la ng uage a nd fully illustrated, it covers every aspect of component-type stereo phonic music systems. The function of each component is described, and ex pla nations of important features and specifications a re included. F or the "do-it yom'selfer," some tips are offered on select ing components in kit form. Price of "This is Ste"eo H igh-Fidelity" is twenty-five cents. Request Stock No. 37 K 387. C-12 • Lafayette Radio, 165-08 Liberty Ave., J a m aica 33, N. Y. is m a king available free of charge a second issue of the ~' Lafayette Semi-Conductor Directory." Expa nded t o 36 pages, this booklet provides engineers a nd scientists w ith a comprehensive, easy to-use lis ting of the la t est in diodes, tunnel diodes, rectifiers, germanium and s ilicon transistors, with selected semi-conductor schematics for industrial circuit applica tion s . All majol' manufacturers a nd types a re listed complete with s pecifications, a pplications a nd prices. The directory is s uitable for loo'se-I eaf insertion. C-13 • Decca Educational Division, 445 Park Ave., New York 22, N . Y., has come u p w ith a n interesting innovation-the "Decca R ecords Educa tional Catalog." Production of the cat a log res ulted from careful study of t h e entire Decca library, aft er which a ll material which is appli cable to educa tion was listed and indexed, by grade a nd teaching requirements . This cat a log will help tea chers find records which will be useful to them in m a ny areas of education. It may b e obta ined by a ny teacher or supervisor b y writing directly t o Mr. B en Deutschma n a t the a ddress shown a bove. 64 AUDIO • MARCff, 1900 N. Y., to meet the dema nds of discerning NEW' TUNERS. .. FROM~ recordists, both a m a t eur and professional. The guarantee promises the Triton t a pe purchaser a r eplacement reel of any American-made brand of the same type should he find t h e Triton deficient in per formance or cha r acteristics for "any H.H. SOOTT magnetic recording tape reason whatsoever, or in any way not as represented." Triton tape is processed with an exclusive "Trionizing" technique, which incorporates three essential tape production processes in sequ en ce, assu ring a product of high quality and reproduc tion capabilities. A ll Triton tape is splice free, wound on non-warp, non-squeal reels, and includes a heavy-duty Mylar leader a t both ends to facili tiate a nd protect Wide-Band FM ...Wide-Range AM Make These labeling of recordings. A tape r etain er clip is s upplied for h olding the tape tight on the reel. For details, contact Brand World's Most Sensitive, Most Selective Tuners! Products, Inc., 39 W. 55th St., New York 19, New York. C-7 The completely separate PM section of the radically new H. H. Scott 330D • Dyna.-Twin Headset. This new h eadset stereo tuner utilizes H. H. Scott's exclusive Wide-Band PM circuitry to assure recently introduced by Telex is intended absolutely drift-free and interference-free reception in even the weakest signal essen tially for private listening to stereo program material. The twin w ide-range areas. Wide-Band design also lets you separate stations so close together on dynamic receivers h ave a frequ ency range of 50 to 15,000 cps. They are engin eered the dial that ordinary tuners would pass them by. The separate AM section utilizes H. H. Scott's unique Wide-Range detector so that, for the first time, you can receive full range AM broadcasts with fidelity and frequency response comparable to PM. Special multiplex adaptor facilities let you' convert to mUltiplex at any time. 320 AM-FM TUNER The many fine fea tures built into this superlative tuner,. including Wide R ange AM and Wide-Ba nd FM, have never been available before for less than $20Q. This tuner is ideal where AM-FM stereo reception is not available. $159.95 * 3l0e FM TUNER This professional tuner is the most sensitive and selec tive available. Its outstanding per formance and sensitivity have made it the choice of universities and laboratories throughout the specifically for headset application and world. Sensitivity 1.5 p'V for 20 db of quieting. a re equipped with two comfortable ear (IHFM rating 2 p.v) $184.95'" muff-type ea rphones. Construction of ·Slightly higher We st of Rockies. Accessory ca se extra. stainless steel, T eflon and Neoprene as sures maximum protection from damage. The Dyna-Twin com es complete with 8- ft. fl exible cord and 3-contact plug or two standard phone plugs. It can be u sed ... ~ H.H.SCOTT ..... either bin a urally or monaurally. Ma nufac tured by Telex, Inc., SL Paul, Minn. C-8 H.H. Scott, Inc. 111 Powdermill Road, Dept. A-3 . Mayn ard, Mass. • Dynald.t stereo PreanLpliJie·r. Available Rush me new catalog and complete technical spe in both wired and kit form, the n ew Dyna cifications on all new H. H . Scott components. kit Model PAS-2 is a deluxe stereo con trol unit which features unus ual versatil ity a nd flexibility along with exceptiona lly Name .•••.••••••••••.•••••••••••••.••••••• · low distortion a nd n oise. Although as many as seven stereo, or fourteen mono Address . ••••• •••.••..•••.•.•..•• •• •..• • •••j phonic, inputs can be utilized, the PAS-2 is simple in operation a nd uncomplica ted City •...... •.•.•...... State ••..•••• " J in appearance. Construction of the instru ment from the kit is greatly s implified Export: Telesco Internat ional, 36 w. 40th St., N.V.C. by the u se of two factory-assembled printed-circuit boards which include about N'rl'Q,I\I;;SGOTT INTEGRATED STEREO ARM AND CARTRIDGE' AUDIO • MARCH, 1960 three-quarters of the components. Aver Dynaco, ·Inc.; 39 16 Pow elton Ave., Phila on either ~ ide ' o'f ' the listening a rea (and age construction time is ·approximately delph,a 4, Pa. C-9 closer to it than the m a in spea kers), the eight h ours. The built-in power s upply augmented stereo sound pattern will be enables operation with any powe r a mpli • Fisher Speaker System. The new WS-1 heard not merely as a stra ight-line cur fier. Frequency response 01' the PAS-2 "Wide-Surround" speaker system offers tain of sound, but 'curved,' totally sur stereo console and component owners rounding the listener." Although the WS-1 reproduces only the middle and high fre quencies, 250 to 15,000 cps, the non-di rectional . character of low frequencies permits the illus ion that the WS-1 is repro ducing bass tones as well. On la te model Fisher consoles-there is a special WS-1 outpu t . Fisher R a dio Corporation, 21-21 44th Drive, Long'Isla nd City 1, N. Y. C-10 • Stereo Test Tone Generator. This device, which is called the Twin Tone and is com pletely tra ns is torized, permits balancing the output of ste reo speakers in a matter of seconds. It is simply plugged into unused inputs of a stereo a mplifier and is is 10 to 40,000 cps ± 0.5 db, a nd intermodu la tion is below 0.05 pe r cent at sufficjent output t o drive a n average amplifier: Equalization c haracteristics a r e closely dis tinct advantages in that it greatly controlled through the u se of 1-per-cent enhances the stereo effect of conven tolerancp. comnonents in the critical n e t tiona l speaker arrangements. According works. Full details are a vaila ble from to Fisher engineers, "by placing a WS-1 ready for immedia t e use. By sliding a switch located on the front pa nel, a con- . stant 1000-c ps tone is· pro'duqed. The vol ume controls on the a mplifier a re then a d justed until the speakers have identical output. A volume control pe rmits adjust ing the signal to any desired level. The Twin T one is powered by an internal mer cury battery. Kinematix, Inc., 1616 N. Damen Ave., Chicago 47, Ill. C-11 NEW LITERATURE • Allied Radio - -Corp., 100 N. Western Ave:, Chicago 80, Ill., announces the re lease of a n ew 36-page boolde t entitled " This is Ste r eo High-Fidelity." Prepared by the publications staff of Allied, with the editorial assistance of Edward Tatnall Canby, columnist a nd chief r ecord r e viewer for A UDIO, this easy-to-understand booklet is a r.ighly informa tive guide for a n yone who wants the' facts on ster eo. Written in straightforward, non-technica l la nguage a nd fully illustrated, it cover s ever y aspect of component-type stereo. phonic music systems. The function of each component is described, a nd ex pla nations of important features a nd specifications are included. For the "do-it your' seifer," some tips a r e offered on select ing comp on ents in kit form. Price of "This is Stereo High - Fidelity" is twenty - five cents. Request Stock No. 37 K 387. C-12 • Lafayette Radio, 165-08 Liberty Ave., J amaica 33, N. Y. is m a king available free of charge a second issue of the ~' Lafaye tte Semi-Conduct or Directory." Expa nded to 36 pages, this bo.oklet provides engineers a nd scie ntists with a comprehensive, easy to-use listing of the latest in diodes, tunnel diodes, r ectifiers, germanium a nd silicon transistors, with selected semi-conductor sch e m a t ics for industrial circuit applica tions. All m a jor manufacturers a nd types a re listed complete with specifications, applications a nd prices. The directory is s uitable for loose-leaf insertion. C-13 • Decca Educational Division, 445 P ark Ave., New York 22, N. Y., has come up with a n inter esting innova tion-the " Decca R ecords Educationa l Catalog." Production of the catalog resulted from car eful study of the entire Decca libra ry, after which a ll materia l which is a ppli cable t o education was listed a nd indexed, by grade and teaching requirements. This catalog will h elp teachers find records which w ill be u seful to them in many a reas of education. It may be obtained by any teacher or supervisor by writing directly t o Mr. Ben Deutschma n at the a ddress s hown above. 64 AUDIO • MARCH', 1960 Dipole Control Resistance radiated from both sides of coupler are WOOD PANEL In order to attenuate the rear wave discernibly different only under very critical listening. Essentially, the radia (from page 23 ) by the proper degree it required sur prisingly little acoustic resistance (item tion from the system is then bi-polar However, our practical aim was, of 4, Fig. 2) placed in the path of the rear with lobes of radiation from both sides. course, to come down to some reasonable radiation to drop it the small amount The frequency response of the system size and still maintain the desired low necessary to move the operating charac comp ared against a _conventional' long frequency response without resort to teristic of the system to fall along the throw, low-efficiency, low-resonance pis any essential baffle in the conventional dotted curve (D) of Fig. 4. Actually, ton in a sealed acoustically stiffened box sense. Some practical size had to be se the rear resistance consists of a con is presented in F'ig. 5. Because the bi lected, and for purposes of preliminary trolled layer of fibre glass backed up phonic coupler is a doubly r adiating ca.lculations we selected a radiator size against a porous screen whose aper system, the curve comparison was made of 22 x 15 in., to be operated essentially tures added somewhat to the effect of in a semi-live room to simulate the con unbaffled. Using the motif of choosing the resistance material. ditions that would hold when the double equivalent radiation resistance values So limited, however, is the effect of poled radiation pattern was effectively leading to different a/A ratios depending the resistive material, that the sound used. Such bi-polar operation would, of upon type of baffle, let us explore, the region of- response say at 40 cps for curve (B) representing a small sealed box, then curve (C) representing the un baffled condition. (Curve (B) is chosen as being typical of the better-quality small enclosure systems in use today). .for the money For this chosen frequency of 40 cps and a piston diameter of 11 in., we again I have a circumference to wavelength ratio of 0.102 which yields a unit radiation circuit by ! tubes by resistance of 0.126 ohms. Now for this 1..-1..- I @ value of radiation resistance for the 12- Se.... lAn1perex in. piston in a small box we' can move ~ , over horizontally directly to curve (C) for the unbaffied condition to get the equivalent piston size for the same level of radiation resistance. But here we must add an interim step. Unit radiation resistance does not give the complete picture, we must deal with total radiation resistance which is a f unction of piston area. Now the 12- in. piston has an effective piston area of about 75 square inches, while our chosen panel has a radiating area of 22 x 15 = 330 square inches, approxi mately 4.5 times as large. Conversely, for purposes of equating the total radia H. H. Scott engineers, preliminary to the design of their tion resistance of the two pistons in Model 299 (40 Watt) Complete Stereo Amplifier, can vassed the industry for tube types offering something question, the unbaffled larger panel may truly exceptional in the way of reliability, low distortion, be considered to have a unit radiation low noise, low hum and absence of microphonics. value lowered by an equivalent factor As has frequently been their experience, the people at Scott found these qualities' best exemplified by Amperex of 4.5, or 0.126/4.5 = .028 ohms. tubes. Thus, the tube complement of the Scott Model 299 Keeping this modified radiation re includes four Amperex 7189's, one Ampere'X 5AR4/ GZ34, sistance figure in mind, we must next get and one Amperex 6BL8/ ECF80. the equivalent "circumference" to wave These and many other Amperex 'preferred' tube types have proven their reliability and unique design advan Ipngth ratio of the 22 x 15-in. piston. The tages in the world's finest audio components. equivalent circumference of this panel about hi-fi tubes Applications engineering assistance and detailed data area turns out to be 164 centimeters. tor hi-fi circuitry are always available to equipment manufacturers. Write: The / A ratio f or 40 cps becomes Amperex Electronic Corp., Special Purpose Tube Divi a sion, 230 Duffy Ave., Hicksville, L?ng Island, New York. 164/860 = 0.192. We now intersect this a/A value of 0.192 with the "modified" AMPEREX TUBES FOR QUALITY HIGH-FIDELITY AUDIO APPLICATIONS resistance radiation characteristic of the POWER AMPLIFIERS RF AMPLIFIERS INDICATORS panel which is .028 ohms. This inter 6CA7/EL34: 60 w. distributed load 6ES8: Frame grid twin triode 6FG6/EMI4: Bar pattern 7189: 20 w., push·pull 6ERS: Frame grid shielded triode IM3/DM70: Subminiature "excla. section, as shown in F'ig. 4, is to fan 6BQS/EL84: 17 w' o push·pull 6EH7/EF183: Frame grid pentode mation" pattern fairly close to the curve for a completely 6CWS/EL86: 25 w., high current, for IF, remote cut·off low voltage SEMICONOUCTORS unbaffled piston. This condition may then 6BM8/ECL82: Triode-pentode, 8 w,' 6EJ7 IEFI84: Frame grid pentode push·pull for IF, sharp cut·off 2N1S17: RF tranSistor, 70 mc be interpreted to mean that the 22 x 15- 6AQ8/ECC8S: 2N1516: RF transistor, 70 mc VOLTAGE AMPLIFIERS in. unbaffled piston can produce radiated Dual triode for FM tuners 2N1515: RF transistor, 70 mc 6267/EF86: Pentode for pre·amps 6DC8/EBF89: Duo·diode pentode power output at 40 cps equivalent to a - 12AT7 IECC81: ITwin triodes, low IN542: 12AU7/ECC82: hum, noise and RECTIFIERS Matched pair discriminator boxed-in 12-in. piston when only a small diodes 12AX7/ECC83: microphonics 6Y4/EZ80: Indireclly heated, 90 mA pel'centage of the rear wave from the 6BL8/ECF80: High gain, triode· INI7A: pentode, low hum, noise and 6CA4/EZ81: Indireclly heated, 150 mA AM detector diode, unbaffled panel is subdued. microphonics 5AR4/GZ34: Inc!ireclly heated, 250 mA subminiature AUDIO • MARCH, 1960 65 course, have been meaningless In an STEREO DEMANDED IT! anechoic chamber, for the real' wave would not have contributed to the re sponse of the system since it would have been absorbed . ,\TANNOYI ENGINEERED IT! Choice of Piston Size and Material It may be asked why for instance was a 22 x 1S-in. piston SIze chosen. There are several facets to the answer. Prima rily, of course, we n'eeded to select a THE NEW "MON ITOR" DUAL CONCENTRIC large p i.ston for radiation purposes, but (the most advanced co-axial to dat e) yet we wanted it to be small enough to be easily accepted into any room acoustic situation without taking up valuable INCORPORATING * New revolutionary magnetic shunt cir· cuit inCI'easing useful low frequency flux floor space. Despite the fact that the by mor e than 200/0. final radiator remained to be the same size as our original trial calculations * Unique treatment of low frequency d ia· phra gm sur" ound providing improved reo the over-all thickness of the entire bi spon se and ~ t ab i lity . phonic coupler assembly turned out to be only 4V2 in. W e knew what we were * New a (,o u stic balance cavity improving h igh f requency response, "educing dis· in for as far as providing a diaphragm tOI·ti on. of these dimensions that would be stable Tannoy engineers have prod uced a speaker of unsur, under the violent impulses of heavy low passed quality, already being used as a 'Moni tor' I)l' world frequency signals. We realize full well wide recording, radio, and television companies . . The ex, the problems that would be encountered tended range ant! increased efficiency of the low freq uene)' were this to be just another paper pulp unit make it ideal for use in relatively ~ m a ll enclosures. whilst still maintaining the "presence" of unrestricted diaphragm. sound. This, combined with the fully integrated sound We had many choices of types of source of the 'Monitor' Dual Concentric makes it especialh wood from which to choose the dia suitable for stereophonic reproducti on. phragm material. As far as theoretical considerations were involved, the weight WRITE FOB DETAILS of the diaphragm was relatively imma TANNOY (CANADA) LTD ., TANNOY (AMERICA) LTD ., terial. Of course, there are practical 36 WELLINGTON ST. EAST, TORONTO, ONT. BOX 177, EAST NORWICH, L. I., N. Y limitations that are imposed, not neces sarily by diaphragm weight considera tion, but by good usable audio power available to the average consumer, and The First Book of its Kind-No Other Like It! we had to design the total coupler piston to be within the power sensitivity of prevalent loudspeaker designs. Yet, not SOUND in the THEATRE withstanding these considerations which by Harold Burris·Meyer and Vincent Mallory however are strictly met, the 'actual weight of the coupler diaphragm is over othing like SOUND in the THEATRE rived systems and equipment specifications. 160 grams. This contrasts greatly with N has ever been published. It is the first Complete procedur.es are given for : Planning, only 30 to 40 grams for the weight of book to set forth in authoritative detail what assembling, and testing sound control installa the "heavy" diaphragms of the presently you can do with sound by electronic control, tions-Articulatin g sound control with other and how to do it whenever the source (singer, elements of production-Rehearsa ls and per musician, speaker, etc.) and the audience are formances - Operation and mai ntenance of present together. The book develops the reo sound control eq uipment. quirements for electronic sound control from the necessities of the performance, the char THE AUTHORS acteristics of the audience (hearing and psy During the past thirty years, the authors have developed choacoustics), and the way sound is modified the techniques of sound control in opera , open·ai r amphi. by environment, hall, and scenery. Sound theatres, theatres on Broadway, theatres on·the·road'and , sources are considered for their susceptibility off·Broadway, in concert halls and night clubs, in Holly· wood and in the laboratory. Some of their techniques are w of control and need for it, and the many tech used in broadcast and recording as well as in perform· Z niques for applying electronic sound control ances where an audience is present. From their laboratory o " , are described and illustrated in thirty-two spe· , have come notably successful applications of sound con· V> / W .... ~ ~ c pr~b ~ems. ,,:,om these problems are de- trol to psychological warfare and psychological screening. '" I : ' W ~ ' .... , I am enclosing my remittance for $10.00 FREQUENCY - CP S Send my copy of Fig. 5 . Low-end response of Bi-Phonic SOUND in Ihe THEATRE poslpaid. Coupler (solid curve) vs. a conventional (No C.O.D., all books sent postpaid in U.S.A. low-efficie ncy, long-throw, low-resonance and possessions, Canada, and Mexico. piston in a sealed acoustically-stiffened Add 50c for Foreign orders.) box. Name ______AUDIO • MARCH , 1960 Address ______ City ______Zone _ Slate ______popular "low-efficiency" systems. Yet the ing system to a halt. However, where electromagnetic coupling between the ovel'-aZl efficiency of this heavy massive there is a considerable percentage of coil coil and the gap, but also because of the piston design is such that a good quality not in the gap, the generated current extra measure of true acoustic radiation 20-watt driver amplifier will all but through the coil and transformer circuit resistance loading upon the large dia push out the walls of the listening room. produces a field that is not completely phragm, which further damps the vi The reasons for this will follow shortly linked wit.h the magnetic circuit, and brating structure. after we have examined an interesting hence the effectiveness of the electrical side effect of this heavy piston. In order braking is reduced, with subsequent de Conclusion to resonate the coupler piston to the de terioration of the transient response. Of Because of its heavy mass and its sired frequency of 30 cps at which it is course, such deficiencies in electrical extremely taut suspension, the coupler producing full output power, it had to damping may be compensated by acous piston motion is extremely restricted, be suspended so extremely taut that the tical damping such as treating the inside enabling high electromagnetic coupling diaphrag'm became almost immobile un of a box enclosure with sound absorbent to be realized between the coil and the less one placed his palm flat against the material to the extent that critical damp gap, leading to high electromagnetic piston and really pushed hard, in which ing may be obtained. efficiency and to optimum damping. Be case it might deflect Ys in. Now we were In the case of the piston coupler de cause of the minute motions of the large beginning to approach our musical in sign, however, such resistive acoustic diaphragm, magnetic linearity is of an strument-with a large fiat radiating damping becomes unnecessary not only extremely high order. All of these fac piston, tautly suspended, and yet capa because of the extreme efficiency of the tors fall into place simply because we ble of resonating at any low desired frequency. Transient Advantage of a Stiff Radiator Because the diaphragm is held so taut, it is almost completely restrained from moving. In fact, it is only under the influence of the strongest percussion notes- the kinds that are actually ear shattering in intensity- that any motion of the diaphragm can be seen. Motion of the diaphragm can be felt, of course, by simply placing the hand directly upon the wooden coupler piston which op erates without being masked by the grill cloth, for in its wooden rigid form it requires no such protection. The' fact that the diaphragm is practi cally immobile, even under the intense driving signals, makes it possible to have almost completely perfect electro magnetic coupling between the entire voice coil and the magnetic gap, and yet maintain excellent linearity of magnetic coupling for even the lowest desired fre quencies. But linearity of motion within the gap is not the only criterion of good NOW .. . for the first time .. . a performance. The electromagnetic cou modestly priced professional pling efficiency between the voice coil stereo recorder that has exciting features found only in the finest and the magnetic gap determines to a instruments. You won't believe it until you see it! great measure the transient response of the moving system, both for the initial FEATHER TOUCH PUSH-BUTTON OPERATION · 4 HEADS, INCLUDING SEPA· step function and the ensuing decay RATE 2-TRACK AND 4·TRACK PLAYBACK HEADS· 3 MOTORS, INCLUDING function. The point may best be under HYSTERESIS DRIVE · MECHANICAL FLUTTER FILTER· DYNAMICALLY BAL lined by considering the transient decay ANCED CAPSTAN FLYWH I;EL • INSTANT SOURCE/TAPE MONITORING· TWO function. In the general case, when the RECORD/PLAYBACK PREAMPLIFIERS · INSTANT START/STOP · AUTOMATIC driving signal stops, the diaphragm will CUT·OFF SWITCH · 3%-7% IPS SPEEDS· AUTOMATIC TAPE LIFTERS· TAPE continue to oscillate uutil brought to a stop by a combination of mechanical, LOCATION INDICATOR· SEPARATE MICROPHONE/LINE INPUTS, EACH acoustical, and electrical factors. Treat CHANNEL. ing first the matter of electrical damp r------l I A A MERICAN CONCERTONE I ing ; in the case of the voice coil that I II com pletely matches the gap configura See th e p h enom enal I DI VISION OF AMERICA N ELECTRONICS. INC. 1\ tion, when the (undriven) diaphragm CONCERTONE 505 I 9449 West J efferson Boulevard I· oscillates, a back e.m.f . is induced within Culver City, Ca lifornia Dept. AU D- 3 I, at your deal er, or send I Ge ntlemen: the voice coil, which in turn generates Please se nd yo ur i llustrated broc hu re on the new CONCERTONE the coupon f or a I I· a current through the circuit which in I 505 STE REO REC OROER , and the name of nearest dea ler. I. cludes the coil and the output trans descriptive br ochure and I I' I Name f former secondary winding. This pro the nam e o f your I Add r ess I' duces the well known electrical braking . n earest dealer. IL ______City Zo ne __Sta t e JI , effect, or damping, that brings the mov- AUDIO • MARCH , 1960 67 postulated a large fiat diaphragm, and impedance of 8 ohms, and will handle because we did it had to become a heavy powers up to 50 watts. FREE one. Since the diaphragm turned out to Objectively, the live room r esponse be a heavy one, it became tightly sus curves shown in Fig. 5 indicate that the pended, and so the radiator circle closes analysis from which the hi-phonic cou TAPE in on itself. pler was derived was basically correct, While this discussion has been mainly and that it is possible to get excellent Your choice of any $7.95 4-track pre about the low-frequency portion of the low-frequency response from a stiffly recorded stereo tape from the U.S.T. suspended heavy inImobile, unbaffled catalog FREE with the purchase of a Bi-Phonic Coupler, let it be said that Nortronics RIP Stereo Conversion Kit. 10he high-frequency aspects have not been radiator. Subjectively, several dozens of CONVERSION KITS neglected. These are handled by a tweeter, listening sessions with outside personnel seen in Fig. 1 as the small circle in the have without exception credited the bi Now you can convert your own tape equipment to upper corner of the panel. It consists of phonic coupler with a "freeness", or 4·track stereo playback or stereo playback/ record with a deep-molded phenolic dome serving as "largeness" of sound as against the these new stereo conversion a semi-direct radiator with a crossover limited spaciousness of the boxed sys kits from Nortronics. All kits come complete with hard· at 2000 cps. The entire system has an tems. IE ware and instructions. WOLLENSAK -REVERE WR·35 Converts 2·track stereo to 4·track play . . $25.50 WR·40 Converts mono machines to 4·track play 32.50 WR·45 Converts any machine to 4·track play/ rec . 37.50 TRANSFORMERS VM (fl'om page 42 ) V·6 Converts all machines to 4·track play ...... $25.50 output is up to the rated figure of 20 to be gained by further reduction, for V·7 Companion Stereo Erase for V·6 kit for rec . 14.50 watts may be computed (see appendix) though reference to Fig. 17 would sug WEBCOR W-6 Converts two-direction machines to 4- to be approximately ~O,OOO gauss, a gest that. the distortion is falling as the track play-includes head shifter _ _ $36.00 value that is well off the curve but it fiux density is reduced, it must be re Write for FREE U.S.T. catalog and specific conversion will be seen that the harmonic distortion membered that I.t. and in consequence the information for yo ur tape recorder. Nortronics stereo tape heads are the very finest available and are used is up to 12 per cent for a fiu x density primary inductance L p and the ratio of by most leading Amencan manufacturers. Nortronlcs of only 3000 gauss and continues to wL to R is also falling. Thus there is no also prod~ces the world's most complete line of tape heads and accessories. increase rapidly at higher flux densities, very significant reduction in the per a quite intolerable result for a high c(;ntage harmonic distortion percentage quality transformer. as the maximum fiux density is reduced. The altel'llative discussed was to use a None of the alternative core materials T .. at present available offer hope of any H CO. transformer having a primary induct E INC. ance of 50 henriES and thus having a r e significant improvement in this situation. 1015 So. 6th st., Minneapolis 4, Minn. sponse that is flat down to about 10 cps. The curves of F ig. 17 also suggest that Circle 68A Reference back to the earlier discussion distortion can be greatly reduced by indicates that such an inductance would decreasing the effective resistance .of the be achieved with a primary winding of source. At fu'st thought, tetrodes and BOOST-O-12 db 2400 turns on the same core. The in pentodes appear appreciably worse than CUT-O-16db creased turns bring the core fiux density triodes in this respect but further in on full load (20 watts) down to about vestigation does not always support this 2-db steps 4500 gauss, the core material having an view. Two EL34's have an effective slope AT effective permeability' of about 3200 at resistance of 30,000 ohms as pentodes in 40 or 60 cps this fiux density. The resultant primary push-pull but only 6000 ohms connected inductance has then risen to about 110 as a pair of triodes, but it should be AND henries, making the ratio of primary remembered that the effective source 3, 5, 10, and reactance to effective source resistance resistance from the point of view of 15 kc approximately 11.5 at 50 cps. Extra harmonic generation is the parallel com polating the curves on Fig. 17 it is bination of valve resistance and load found that the harmonic distortion is resistance. As pentodes, two EL34's re about 1.7 per cent at f ull load, a very quire an anode to anode load of 3400 ~ROGRAM considerable improvement in perform ohms, making tha effective source r esist ance. ance about 3000 ohms. As triodes the EQUALIZER These figures make it quite clear that valve slope resistance had dropped to when a high-quality amplifier is being 6000 ohms but the optimum load has The 251-A Equalizer is a passive LCR designed, the frequency response must risen to 10,000 ohms, making the effec bridged-T network with two sliding levers extend well below the nominal lower tive source resistance about 3,700 ohms. for attenuation and equalization, one for frequency limit required by the signal Thus in this instance triode connected low frequencies and one for high. This spectrum if harmonic distortion is not valves are slightly worse than the same type of equa lizer has long been the standard for corrective equalizatior:1 in to be intolerably high on low-frequency valves pentode connected. sound record ing. sIgna-Is. In this particular, though typi Ultra linear. operation of pentode or Impedance : 600 ohms Leyel : - 70 to + 20 dbm cal, example, the response must be flat tetrode valves offers a significant reduc Insertion loss: 14 db Power required: none down to 10 cps in order to achieve dis tion in effective source resistance, an Panel size : 3 V2 " x I V2" Net price: $260.00 tortion values as low as 2 per cent at other reason for the obsolescence of 50 cps. "straight" operation of pentodes or ELEC1RODYNE The reduction of fiux density appears tetrodes. Negative · feedback, either over CORPORATION advantageous in reducing harmonic dis the whole amplifier as a distottion re 503 South McClay St., Santa Ana. Calif. tortion but to a great extent this is an ducer, or from the anodes ·of the output New York City: Robert Marcy and Assoc .. 1776 SWay . illusory advantage. Provided that the valves back into the cathode circuit of Send for /l1te.1 call1/''11 fiux density is kept below about 5000 an earlier valve as a source impedance Circle 688 gauss at full rated power, there is little reducer, has great advantages and is in 68 AUDIO • MARCH, 1960 No matter how wide the frequency respons'e of -your-present pickup, proper fact the only method of obtaining dis stereo effect cannot be assured unless tortion values in the region of 0.1 per the cartridge preserves perfect phase cent at f ull rated load. IS Vf)I]ll separation throughout the midrange and high frequencies. Unfortunately, many A p PENDIX respected pickups have no pha se control The flux density B in a tm nsformer core f ~illlrrllI I) f.l~ beyond five or six thousand cycles . can be calcnlated from the following equation If a cartridge lacks this separation, the V x 10' . balance control on the preamplifier can be B = 4.44 t T A lines/ sq. cm. TRULY turned wlth, little or no result. Both the where B = fl ux density ESL-C99 Micro/ Flex * and the ESL-C100 V =v oltage across winding Gyro / Jewel * cartridges are distinguished t = f requency T = nnmber of turns on winding by their near-magical re sponse' to the A = core area sq. ems. balance control. In the example used in the discnssion V Prove this for yourself by comparing the is the voltage developed across t he anode ESL with any other cartridge on a good load RL of 3400 ohms at the rated output stereo record. For example, " Persuasive power of 20 watts. This is Percussion " (Command Records) demon V= yW R = Y 20x 3400= 260V. L strates the striking difference pha se Using a core having an area of 1.5 sq. ins. control can make. (10 sq. cms.) and the 2400-turn winding, the core fiux density B at a frequency of *The superb He lV ESL-Cgg M1CROI FLEX 50 cps is (pi crured left) is oHly $4 g. 5 0 at YO Hr dealer's. 260 X 10' Th e lVorld stereo stalldard, tile ESL-C 1 00 B = 4.44 x 50 x 2400 x 10 = 4900 gauss. GYRO / } EWEL, is $ 10 0 i flclHriiflg trm/stormers. At this value of fiux density t he effective permeability may be taken as 3200 and t he inductance of the 2400-tUrll winding is then FOR LISTENING AT ITS BEST L 3.2 x 2400' x 3200 x 1.5 110 H . p 8 X 10' = ennes. Electro-Sonic Laboratories, Inc. L at 50 cps = 34,400 making roL/ R = 11.5 The distortion where B = 4900 lines/ sq. Dept. A · 35-5 4 Thirty-sixth Street. Long Island City 1, N . Y. em. and L / R =11.5 is, from Fig. 17, ap Ci rcle 69A proximately 1.6. per cent. lE " POWER SUPPLY (Continued f rom p age 19) the grids for cut-off will be a f unction of the ampliiication factor of the triodes. I n order to achieve the maximum pos sible output voltage, R J and R 2 should be matched to compensate for t ol e ranc e~ in Rs and R 6 ) in CJ and C2 ) and in the location of the center tap of the trans former winding. Matching may be ac complished as follows : with R 4 shol't circuited, and with power applied to the transformer, R J and R z should be chosen so that the alternating voltage at the grids is zero. This match is not very critical, and a suitable pair of resistors should be found among five or six r e sistors of ten-per cent tolerance, FEATURES: It is evident from Fig. 3, which plots ,. Can re ce ive ste re ophonic broadcasts of both AM-AM and AM-FM indepe nde ntly at the 4-germanium diode s, 23 tube s 6BQ5p.p.x 2 same tim e and facilitate s re ce ption of any Maximum Power Out put: 1 5W -1 5W kind of broadcasts- AM, SW, FM. 400 Frequency Characteristics: 40 c / s~ 7 0K * By pushing th e "presenc e switch", it can re c ! s, within -l db (at lOW output) produce powerful low sound whi ch has I- Distortion: 1 % at 14W output '" hitherto not b een possible. 0 300 > * Easy to see " glamo ur magic e ye" is equipped Gain (input for lOW output): TAPE .... 1.23mV MAG .. · .3.17mV I for tuning indication. MIC _.,. 1.34mV X- TAL .... 54mV ~ 200 * By only changing the mode switch, output of ~ as much as 15W-15W for ste re o and 30W for AU X . .. .74mV 0 ordinary broadcast can be obtaine d. Frequency Response: > 88-108Mc! s x 2 for FM I- 100 * A highest class versatile "mammoth" amplifier that can also be used a s a crossover 3500c/s 535Kc !s ~1605Kc ! s x 2 for MW ~:::> 3. 5Mc ! s ~ 10Mc / s for SW 0 a channe l amplifie r. SANSUI ELECTRIC CO., LTD. Izumi-c ho, Sugin ami-ku , To kyo, J apan R4-MEGOHMS 460, Fig. 3. Output voltage variation with re spect to potentiometer setting. Circle 69B AUDIO • MARCH, 1960 69 trol is accomplished by introducing a series resistance element, leaves much 400 to be desired. Consequently, any adjust ments of voltage should be made under load conditions. The regulation charac teristics of the circuit are shown in Fig. 4, which plots output voltage against curren t for several settings of the con troL However, the poor regulation char acteristic does not constitute a serious drawback, as regulation is seldom a sig -CAPACITOR INPUT ----CHOKE INPUT nificant issue with the experimenter, if the control can be adjusted with the what's th I ? 10 20 30 40 load in place. e ang e. OUTPUT CURRENT-MA Unexpectedly, the regulation of this 55 l±51 degrees-a whole diamond-hand polished • circuit is better with a capacitor input Fig . 4. Power supply regulation charac· degrees? To fit standards fi lter than with choke input, for the fol Why 55 (±5l teristics. set by record manufacturers . Styli lowing reason. With choke input, bursts of current through the tube generate ground mechanically may have angles voltage against the resistance of R 4) that up to 85 degrees. The Duotone stylus is a potentiometer of reverse logarithmic positive voltage pulses at the cathode. hand ground and polished as close to taper (such as IRe taper P or Q) will These pulses increase the tube's internal record·groove requirements as possible. give. the most satisfactory variation of resistance by driving the cathode more A whole diamond, 2/ 3 embedded in the stylus, that can 't break off like a welded output as a function of pot setting. To P ARTS Lrs'r chip-guaranteed-and the protection improve the r esolution of the control of a microscopic inspection for ± .0001 setting, a padding resistor, R 3 ) can be 0.1 ~tf , 600 v, paper tolerance in its radius-that's the angle. connected in parallel with the potenti 8 !Af, 600 v, oil filled ometer, so that the output reaches zero 4 Hy choke, d .c. resistance, 250 ohms. just as the control setting approaches R"R, 100 k obms, 1 watt the full counter-clockwise position. It is R, p adding resistor, about 2 megs \\\\\\,\\\\~ suggested that component values be (see text) DIAMOND NEEDLE chosen so that zero output is reached a 2 megobms, potentiometer, reverse log taper (IRe t ype Q·17·139, Keyport, New Jersey little before the end of rotation, to in "Q" taper, or equivalent) In Canada: Ghas. W.· Painton, -ltd., 10ronto· sure that the voltage can always be set 2.2 megs, l./2 watt Circle 70A at zero in spite of changes in parameters SPST switch due to aging, temperature changes, line Power transformer, 280·0·280, 6.3 RADIO SHACK FLASH! v at 2.5 amps. voltage variations, and so on. If a fur 6AS7G tube. ther improvement in resolution is de sired, a vernier adjustment can be added, p ositive than the grid, and thereby de in the form of a lOO-k or 200-k rheostat crease the d.c. output voltage. A capaci in series with R •. tor at the input to the filter smooths out CAUTION: If a lal'gel' powel' tmns the cathode voltage. For comparison fMmel' .is used to pl'o vide higher output purposes, the power supply regulation For the newest and best voltages) the effects of incl'eased POWM' .with choke input filter is also shown in in electronics equip- dissipation in the l'esistance elements I ment-stereo, hi-ti, ham Fig. 4 '(dashed curves). radio, tapes-mail cou must be accommodated, I1!nd the capacitor The output voltages plotted were oh pon today for Radio voltage mtings should be revised as ap Shack's latest FREE tained with the filter circuit shown in 312 page ca talog. Also p ·opl·iate. Fig. L However , any conventional filter get ev ery n ew edition would be suitable, with some change in for n ext 12 months, Regulation Free. Satisfaction guar output voltage and regulation resulting anteed or your money if the circuit values are changed ma back. Mail coupon now. The regulation of this power supply, as is always the case when voltage con- terially from those shown. 1E ~Transistor Battery Radio 19.95 Value only $995 . Shack transistor bat Exc1usiv.e ~ a fl o2Ysx 4X.l ~ inches i~ s i z.e~ teryrndlO. n y s 10 ounces. BUllt-1n External appear· W eighs lesd, traite antenna. Conelrad ance of the varia ::~;:g :, nb a nd~me molded case. ble power supply. IR~;Sh~Co"rP.:'jjiic;,;;;~iibA-;;:'-----'1 I Boston 17, Mass. Dept. 60C12 J Send FREE Electronics Cotalo9---:Also every new I I issue for 12 months, a full year's subscription Free. I Nome I 1 Address ______I Po.toffie. I Lor City ZO.!!!-=-~!!..--=-=--! Circle 70B 70 AUDIO • MARCH, 1960 ABOUT · MUSIC try (from page 61) . writer fears that our concern with fac· encountered a composer who was deceived this similes "degrades the very artists upon by having his music released on a disc; I whose reputation the production and dis do not seek facsimiles in the concert hall; tribution of these facsimiles depend. It and, as for the "limited areas caught by deceives those composers who, through over the facsimile process," where has Mr. Lamb simple exposure to the limited areas caught by the been for the past ten years' The recorded facsimile process, are in danger of taking repertoire available to the inquiring musi too little note of the opportunities and the cal mind is astonishing in its scope and responsibilities beyond. And it can mislead diversity, and provides a valuable adjunct test audiences into seeking, in the concert hall, to the often weary format of the majority those qualities that distinguish the fac of concert seasons in America. ... proves new simile, and into evaluating what they hear Behind all of Mr. Lamb's argu,ments lurks the man-against· the-machine bugaboo. in terms of its faithfulness to copies and EMPIRE 98 most In this case the machine is an audio instru to the codes of copyists." ment, and, as with all sophisticated instru perfectly balanced Well, that's quite an indictmentl I must ments, its value is entirely dependent upon say, however, that I cannot share any of the person who uses it. At its worst, it is transcription ar Mr. Lamb's apprehensions : I know of no ' nothing more than audio wallpaper; but at artist who feels he has been degraded by its best, it can bring us truly enriching ... finest the mere act of recording, nor have I yet musical experiences. IE for stereo and AUDIOCLINIC monophonic (fl'om page 4) records! quency transient came along and charged betweeu the capacitor and its grid return the capacitor negative. As a result, the which will serve to prevent low-frequency grid would go negative, and might go far transients from appearing on the .grid. We do not make the coupling capacitor so 1. With an Empire 98 mounted on a turntable enough negative so that the tube would be board and fitted with a ca rtridge. adjust completely cut off. The length of time that small in value that the audio response is restricted. We want to remove the 1 to counterweight until arm is balanced. 2. Dial this cutoff would continue would depend stylus pressure desired (one gram for each lO-cps transients which are not heard any upon the size of the coupling capacitor and marking on the built·in calibrated gram scale). how. upon the size of the grid resistor with 3. Place a record on turntable. Set stylus in A O.l-J,Ii capacitor is certainly a large groove. 4. Now, tilt the board. 5. Note: The which it is associated. By making the ca value, and if it is associated with the usual arm remains in balance and the stylus re pacitor relatively small we cl0 two things: O.5·meg grid return, a long time:constant mains in groove at every angle, even if held (1) we eliminate a long time constant dur will be present which will definitely be of upside down. In the Empire 98 arm the lateral ing which the signal may blank out, and sufficient strength and length to cause the pivot is located on the " balance axis"-in a (2) we introduce a voltage division action effects noted above. IE straight line with the' counterweight and car tridge. Arms which place the pivot point out· side the " balance axis"-will swing with every change in angle. The Empire 98 <;Idjusts stylus pressure without disturbing the inherent bal· AUDIO ETC ance. Once pressure is adjusted it does not vary even with warped records. Arms which (from page 44) move the position of the counterweight to obtain stylus pressure are inherently unbal· for .stereo, especially for four-wire stereo. You see (I hate to confess it, but ...) anced because they shift the weight to the Second, the viscous damping is potentially the sliders ill this Japanese arm were just cartridge and create an inequality of mass on dangerous in stereo; a viscous impediment each side of the pivot. to up-and-down motion can put enormous PLAST IC SHELL forces, relatively speaking, on the vertical WHAT ARM BALANCE MEANS TO YOU. The compliance of the stylUS, especially when '\ Empire 98 is so precisely balanced it will track the record is warped-has waves in it. Lots a record without favoring one groove wall or of them do. I found that without even the other, even on a non·level turntable. This trying to measure it, I could hear definite assures equal output to both stereo channels, distortion in my stereo sound when the reduced distortion, minimum record and damping was heavy. Fortunately, the ",ON" M"M stylus wear. 12" arm, $34.50 damping in this arm is variable, via a ~'"WEIG HTING set· screw on the top of the pivot; so I NON-MAGNETIC EMPIRE 88 STEREO/BALANCE CARTRIDGE. loosened it up until it was :virtually gone MOVABLE MAGNETIC METAL ARM Superior moving magnet design is and the arms moved free. That did it. REAR WEIGHTS combined with a new 4·pole, hum· But another odd habit of this type of balanced construction for full viscous-damped arm made more practical channel separation, balanced high trouble. The arm "sits" on its pivot and output from both channels. High will wiggle freely in any direction. It vertical and lateral compliance, therefOl'e seeks its own level and if the minimum dynamic mass and low turntable isn't precisely level will tilt the tracking pressure reduce record stylus at an angle to the record. Now this is no great problem if your table is flat, and stylus wear to an absolute mini· but as I have said, most people's aren't. CAR TRIDGE SLIDER .mum. With diamond stylus, $24.50 I kept seeing the tilt, one way or the other, with my naked eye, and wasted much time AUDIO EMPIRE in minute level adjustments. But a more precision products of Dyna·Empire Inc. immediate tilt trouble arose to complicate fine, but the weighting inserts just didn't 1075 Stewart Ave., Garden City, N. Y. the issue. Nickels and dimes. tUl'll ont to be very practical-or least not Circle 71A AUDIO • MARCH, 1960 71 NEW! "the hest of AU 0 10" No. 124 No. 120 A new compendium of AUPIO knowledge. THE 4th AUDIO ANTHOLOGY Here is a collection of'the best of AUDIO-The. AUDIOclinic $2.95 Postpaid o y Joseph Giovanelli ... noted audio engineer and the original high fidelity answer-man-EQUIPMENT PROFILES edited by This is the biggest Audio Anthology ' ever! C. G. McProud ... Editor of AUDIO. Here is a wealth of'hi-fi Contains a wealth of essential high fidelity and audio information. Answers to the most important issues know-how in 144 pages of complete arti in high fidelity and a valuable reference on the performance of cles by world-famous authors. leading makes of high fidelity components. Volume I $2.00 NEW! Greatest Reference Work o.n Audio & Hi Fi No. 123 nThe AUDIO. Cyclopedia" by How~r d M. Tremaine Up tf) tne minute, inc/atling steref)! • 1280 pages • 3400 topics • 1600 illustrations . Here is one single volume with the most comprehensive cov erage of every phase of audio. Concise, accurate explanations of all audio and hi fi subjects. More than 7 years in prepara tion-the most authoritative encyclopedic work with a unique quick reference system for instant answers to any question. A vital complete refe rence book for every audio engineer, tech ilician, and serious audiophile. $19:95 No. 115 No. 112 McPROUD HIGH FIDELITY OMNIBOOK TAPE RECORDERS AND TAPE RECORDINC Prepared and edited by C. G . McProud, by Harold D. Weiler publisher of Audio and noted authority and pioneer in the field of high fidelity. A complete book on home recording by the author Contains a wealth 'of ideas, how to's, of Hi{!.h fidelity Simplified. Easy to read and what to's .and when to's, written so Jearn the techniques required for professional re plainly that both engineer and layman can appreciate its valuable context. sults with home recorders. Covers room acoustics, Covers planning, problems with decora microphone techniques, sound effects, editing and tion, cabinets and building hi·fi furni splicing, etc. Invaluable to recording enthusiasts. ture. A perfect guide. $2.50 Postpaid. Paper Cover $2.95 Postpaid. by Edgar M. Villchur You save almost 60% with this combination of valu able audio and high fidelity books. The 3rd AUDIO Right up to date, a complete course on MARCH ANTHOLOGY ($2.50); Tape Recorders & Tape sound reproduction. Covers everything from the basic elements to individual Recording ($2.95); Handbook of Sound Reproduc chapters of each of the important SPECIAL! tion ($6.50 ) components of a high fidelity system. TOTAL VALUE OF ALL THREE $11.95 Regularly $6.50 .. . offered for a limiled SAVE Your cost ONLY $5.00 POSTPAID time at only $3.75. This offer expires March 31, 1960 SPECIAL! You pay only $2.75 for this $6.95 Cood only on direct sale from Publisher Order #OS63 book when you order it w.ith any other AUDIO Bookshelf RADIO MAGAZINES, INC., Dept. 62 P.O. Box 629, Mineola, New York Please send me the books I have circled below. I am enclosing the full remittance of $ ...... (No. C.O.D.) All U .S.A. and CANADIAN orders shipped postpaid. Add SO¢ ror Foreign orders (sent at buyer's risk). BOOKS: 110 112 115 120 123 124 0563 NAM~E ______ADDRESS ______ CITY------______ZONE--STAT~E ______WHEREVER YOU for my " ~~ftipie-cartrid ge situation. We thin mu-metal, in the 'shape of transformer ' tried to pre-adjust the weight for each in leaves or the like, and my assist ant cut the installation, but it wasn't easy. I some of this np. A n arrow (i") strip was MAY GO found, in my perennial haste to get my placed on the flat top of the arm (which work done, that generally the cartridges is non-magnetic) for about seven or eight were too light and that a small and judi inches, from the pivot down to the neck of MUSIC IS ALWAYS ciously placed weight on the arm brought the arm "liead," and sealed down neatly things to the proper state. It was some with a half-inch strip of plastic sticky tape times a bit of metal or a washer or bolt, ove)' it. On the rear overhang we put a WITH YOU but more often and conveniently, a coin. shorter strip in the same way. So s i~ple, and so handy. We had experimented to find the proper It did work, I asure yuu, and. I achieved weights and my assistant now proceeded very proper stylus forces. (I can no')' judge to cast them. He mounted a small piece of' the force fairly well by the effect on my bar magnet , of the sort you can buy for finger t ip, even without f ancy measure household use, into a plastic holder and NEAT meuts.) The hitch was that they were added weight via Wood's met al, whie- h tipsy. If the coin wasn't exactly in the melts in boiling water. As an industrial middle and the turntable exactly flat-or engineer he has this sort of thing at his equivalent combination-the arm quietly finger tips. The plastic is a sort of fl at leaned sidewise and the coins kept falling t ened tube section with one end sealed, TRP-82 off, anyhow. maybe three-quarters by a half by a quar ter inch. The finished weights are neatly I'll put aside any account of my other colored, a pair of heavier magnet-weights adapting procedures for this interestingly for the rear-end balance (two for more l .. ·Complete set outdateg arm, except to say that we did r ange) and a much lighter one, different fix it up for multiple-contact sliders (we color, to do the front-cnd sliding adjust have actually used fiv e contacts) via a spe ment_ They stick to the mu-metal strips 2 .. Band radio cial and ingenious plug and socket; we very nicely and won't fall off ShOl·t of a installed a mono-stereo switch (paralleling m ajor displacement of the tnrntable box. the two leads for mono) and even an auto (We put a small plastic box near the turn matic ground (more on this, later). It was . 3 .. ·Speed record table to take them when moving day ar stereo in all respects now, and except for rives.) The mu-metal strip itself with its the stylus-force problem was highly satis factory. neat plastic tape covering is a guide for player centering and thus minimizes the problem 'Well, I got one whiff of the zero-balance of the leaning stylus. idea and decided at once that it could be The pl'ocedure is simple. P lug in your 8 transistor high sensitivity, combined with a better weight system for cartridge, monnted in its slider. Put one the Japanes!l arms before we finally re or both r ear weights on the mu-metal strip SW /MW . radio phonogragh placed them. What we needed were two and adjust until the cartridge flo ats. Then Enable to play elements. (1) An adjustable weight on the put the front weight O'n its longer strip EP discs by 6 rea}' overhang, for zeroing out the cart and slide forward to the proper stylus pc:s of UM-r ridge balance. (2) A movable, adjustable force. (1.5) battery. weight-much less heavy-to slide along It works just fine- and I have a very the main body of the arm for the stylus rough calibration in garms marked on the force desired, after the zeroing process. A plastic strip, just for looks. It could, of third necessity (3) was a means to attach course, be made aCC Ul'a te since this scale these weights to the arm, yet leave them is invariable, ouce the cartridge's weight movable for adjustment. That was tricky, has been balanced out to zero. and you wouldu't guess our dizzy answer. But I think I like the more professional Magnets and mu-metal strips. arrangement on the Empire 98 arm even I happened to have some odd pieces of better. .1£ liGHT LISTENING .. .. (from page 10) MONOPHONIC show-The Little T'in Box. It's one band you'll be tempted to repeat as a procession of Jerry Qock: Fiorello po liticians takes turn explaining, with deeply injured innocence', how the loot happened to Capitol WAO 1321 'YOI'm its way into their tin boxes. Capitol's The wail of a siren at the start of the so und is brigl,lt without straining for eft'ect. overture notifies the listener that this musi The miking of the orchestra is particularly cal biography of one of New York City's more successful in getting the touches that under popular mayors isn.' t going to take itself too line the action in any polished show. seriously. The authors selected the segment of Fiorello La ' Gual'dia's '·career that would Percy FaJth: Bouquet provide the most 'colorful backdrop for the . Columbia 'CL 1322 show. This is the story of his personal life while getting started in politic~ during the Ray Ellis: I'm 11'1 The Mood For Strings wild administration of ' J'mmy Walker. Capi 'MGM E 3779 .51C-3779 tol's original cast 'recording 'proves one point immediately. The producers of Pajama Game, Perseverance apparently pays oft' in the re Damn Yankees, and West .Side- Story can turn cording studio even when background music out a hit show on almost any subject and is on the docl{ et. For years, Columbia has as give it enough color a nd life to r egister in n signed the same recording engineer to the recording. Politic8 and Poker, one of the hit Percy Faitll. sessions to ensure a continuity songs, estaulishes the atmosphere early in the in miking in ethods. In this Bouquet album record. Unfair in traduces Tom Bosley in the (Solitude, Ebb T ide, L au,-a, et.c.) Percy title role as he coaches the female employees Faith dispensed with hi s normal complement of the Nifty Shirt Waist Co. in picketing of brasses and winds. The orchestra was d i techniques. Fiorello's campaign song when vided into four sections for easier control at running for Congress, The Nmne's LaGua,·dia. the console-two banks of violins, one sec t ion of low strings and a section occupied by is delivered in several languages. The love piano, harp, guitar, and vibraphone. songs are handled in ladylil{e fashion by Pa The MGM project with Ray Ellis doesn't tricia Wilson, Pat Stanley, and Ellen Hanley. display mn ch luster. A dull stUdio diminishes Eileen Rodgers and a girl's chorus introduce· some of t he natural appeal in the straight some of the 'corn of the times in the 'Valker forward string arrangements. E a ch tune is ca mpaign song, Gentleman J i mll.Y. On the evi further burdened with a wordless choir-a dence of this record, the production number device that, one of these days, is going t() NEAT ONKYO DENKI CO .. LTD. most enjoyed by the cast occurS late in ,tile become old hat even at the consumer level. No.4, l-chome, Kanda Hatagocho, Chiyoda-ku, Tokyo, Japan AUDIO , . MARCH, '1960 73 the only Les Baxter: The Sacred Idol Capitol T 1293 r--CLASSIFIED-- Do people still buy this sort of thing? Somehow I 've been under the impression that Rates: 10C per word per Inserti on for noncommerc ial music dealing with Aztec gods went out with adverti se ments ; 25C per word for commercial adver· tlsements. Rates are net, and no discounts will b. E t he early talkies yet here it is . again on a allowed . Copy must be accompanied by remittance In brand new disc from Hollywood. The men of full , and mu st reach the New York om ce by th e way "to continue getting Les Baxter's orchestra have been hardened to first of the month preceding the date of iss ue. this activity in previolls excursions to non existent faraway places. The twenty-five-voice chorale does its best to show in terest in selec tions with titles such as Ga,'dens oj the Moon, TRADE UP TO STEREO: Largest selec F,."it oj D 'l"e(L11I 8, and Pyram.'id oj the Sun. tion of new, used hi-fi components. ProCes sional service facilities available. Write Audio Exchange, Dept. AE, for trading information. Peggy Lee: latin Ala l ee 153-21 Hillside Ave., Jamaica 32, N. Y. Branches in Brooklyn, White P lains, Ma n Capitol T 1290 hasset. Once committed to t he concept of Broa,l· HIGH FIDELITY SPEAKERS REPAIRED siancefj{°E way show hits in Latin tempo, the producers Amprit e Speaker Service of this latest P eggy Lee album uidu' t settle 168 W. 23rd St., New York 11, N. Y. CH 3-4812 for balf-wny measures. A wavel'ing in resoh; ~ ENJOY PLEASANT SURPRISES? Then high fidelity stereo would probably have undermined the entire write us before you purchase any hi-f:i. You'll project. After all, t he conversion of Okla· be glad you did. Unusual savil!.~s. Key Elec cartridge is to be h oma's S1t1Tay with the F"inge on Top into tronics, 120 Liberty St., New York 6. N. Y. a cha·cha·cha leaves little room for inde· EVergreen 4· 6071. cision or weakness of nerve. Drawing upon the pool of Latin instrumentalists in t he Los WRITE for confidential money-saving [ll'ices Angeles a rea, conductor Jack Marshllll has on your H i-Fidelity amplifiers, tuners, spea k e rs, tape recorders. Individual Quotations assembied a g roup capable of sailing through only; no catalogs. ClaSSi fied Hi-Fi Exchange, a dozen show tunes as though t hey were the Aft. :;:375 East 65th St., Brooklyn 34, N. Y. brainchild of some South American song your replacement stylus smi th. Four Afro·Cuban drummers add fur UNUSUAL VALUES. Hi-Fi components, ther spice throughout the a lbum. Peggy Lee tapes and tape recorders. Send for package is a genuine quotations. Stereo Center, 18 W. 37th St., displays, in addition to the easy warmth that New York City. always has been her trademark, a poise that should be the en vy of every gal who faces 11 SALE: 78 rpm recordings. 1900-1950. m ike in t he line of duty. Recommended more F ree lists. Collections bought. P. O. Box 155 for its audacity than as a possible start of (AU) , Verona, N. J. a general t rend. SHURE RENT STEREO TAPES--over 900 differ precision made stereo ent--all major labels. Free catalog. Stereo Buddy Cole: Th e Most Recorded Songs Parti, 1608-H Centin ela Ave., Inglewood 3, California. Of All Tim e Warner Bros. B 1357 INDUCTORS for crossover n etworl;s. 118 There is Ii ttle need to check the accuracy types in stock. Send for brochure. C & M of the statistic claimed in the t itle of this Coils, 3016 Holmes Ave., N.W., Huntsville, a lbum. The ten can 't-go·wrong tunes include Ala. STYLUSCircle 74A St(Lr Dust, Begin the Beglline, Body and SOliZ, St. Louis BZues, Septe1nbe,· Song, and Over WESTERNERS! SAVE l\IONEY on your components! Free delivery and advisory the R(Linbotv. The Cole keyboard style retains service. Special prices on package deals. its incisive command of color without lapse Charles Munro, Audio Components, 475 L in into mannerisms. The sound has a tinge of den Ave., Carpinteria, California. commercial reverberation although in no where near the quantity found in some Holly FOR SALE: "Hi-Fi Music at Home," Nos. wood pop r ecordings previously released on 1- 38; " Audiocraft," Vol. I complete: AUDIO, Oct. '54, Dec. '54, Feb. '55-Dec. '59. Best th is la bel. }E Offer. Snader, 105 E. 35th St. Wilmington 2, Del. LOW QUOTES on everything. Hi-fi & COMPLETE! THE "INSIDE S tereo t apes. Bargain list. HiFi, Roslyn 4, Pa, EXCHANGE: Altec 633A microphone. "From Tinfoil to Stereo" SAVE YOUR rugged non- or semi·directional dynamic, The Evolution of the Phonograph famous " saltshaker" in perfect condit ion, fOl' an AR-1 or KLH-4. R. K essler, 1300 York by Oliver Read COPIES OF Ave., New York 26, N. Y. & Walter L W elch AUDIO and "Radio News" Jan. '50- Dec. HERE IN WORDS AND '54, each set $10; Sargent-Rayment SR-80S RARE PHOTOGRAPHS AM-Fi\1 tuner and preamp, $75; Atlas HF-1 is the whole fascinating tweeter, $15. All Lo.b. Oakland. Snyder, 409 history of the phonograph Orange St., Oakland 10, California. -the absorbing story of AUDIO the m e n and exciting HI-FI COMPONENTS, tape recorders. events in its d e velopme nt! • Each file holds a Attractive and Special quotes Dynakits, Bell equipment. Bnyln Co., 1470·0 E lmer Road, Wantagh, N. Y. You'll be fascinated by t his full year's copies. practical for your m asterful aecoun t. Covers • Jesse Jones Vol home or office FOR SALE: ACA Model 808C Twin-Trax tape everything: m a n's earliest recorder mechanism, 15 ips, in good condition, dreams of imitating soundj ume Files for every $40; E lectro-Voice Model 650 microphone, $30 ; t he Edison tinfoil phonograph; earliest proto publication. 3 for $7.00 Jackson a udio oscillator, ' $20. Donnie Brown, types; the patent struggles; cyHnders and discs; 6 for $13.00 1305 Watson, Moberly, Mo. t he coin p h onograph; the intel'nal h orn; contri. • Covered in durable ORDER NOW - s e nd butions of radio and sound pictu res; war of the leather like Kivar, SELL : E lectro-Voice T250 driver, X6 net record speeds; component systems; tape VS. d iscs check or money order work, 6HD horn, $ 75; Jim Lansing 375- -right down to stereo. A wonderful book for title embossed in 16 driver, N500 network, 537·509 horn-lens , every audiqphile and phonograph connoisseur. KI gold. MAGAZINE FILE CO. $275 ; Univer sity 15W woofer, $60. John 576 p.; 6 x 9"; hundreds of rare photos. 520 FIFTH AVENUE Haner, 683 Locust St., Galesburg, Ill. Special Pre publication Price, only $895 Soli,foclion guaranteed NEW YORK 36, N. Y. TEST YOUR AUDIO ACUITY! Ultra sensitive recording techniques capture and' ...... ,~ .. DESCRIP T IVE FOLDER amplify t he essence of sounds that ordinarily go unheard. Using these techniques we've r e • HOWARD W. SAMS & CO., INC. ...-,.. FREE UPON REQUEST : 1738 E. 381h St., Indianapolis 6, Ind. corded the e veryday "small" sounds of the home. Tbe r esults will challenge your sound • Send ..... copy(i e,) of " From Tinfoil 10 Siereo" (EPR . l ). judgment. Entertaining and informative. In $ ••. ....•. e ncl osed. troductory offer of twenty sound surprises. on tape for $2.00 postpaid. Tapes a re full ·: Ncme ______WANTED: 18·inch Cinaudagraph speaker. t r ack 7 116 ips recordings made on Ampex. Box CC-1, AUDIO, P. O. Box 629, Mineola, Audio Specialities, Dept. A, Box 8203, San • Address ______New York. Antonio, Texas. SE VERAL Audio Process model AP-11 low FOR SALE: Scot t 130 ster eo 'preamp, lik e : City______Zone_Stcte ___ resonance, damped cone woofer s; 4 .5 lb, n ew, $95; Grado stereo arm, $15: Shure· magnet, $14 each. Requires recommended 2 M3D stereo cartridge, almost new, $20. ·...... cu. ft. sealed baffle. G. Cain, 15 Manet Circle, Houlanel, 151 Hartford Tpke., Hamden 17, Circle 748 Chestnu t Hill, Mass., LAsell 7·0826. Conn. 74 AUDIO • MARCH , 19601 C. Robert . Paulson has b een appointed mana ger of the Professiona l Audio Pro ducts Division of Ampex Professional Products Company. H e r ep laces Frank G. Lennert who will rema in w ith the com pa ny in an advisory capacity on a udio matters. As w ell as tal Circle 75F Circle 75C AUDIO • MARCH, 1960 75 ADVERTISING INDEX KT-250A 50 WATT INTE GRATED STEREO AMPLIFIER • A completely new ste'reo high fidelity amplifier Acoustic Research. Inc...... _ . .. .. _ . .. 41 with a high quality of reproduction, versatility of Acro Products Co...... 2 operation, and distinctive styling. Advanced Acoustics, Inc...... 6 A full range of controls enables you to enjoy the Allied Radio Corp ...... 53 utmost in listening pleasure in any situation. De Altec Lans ing Corporation ...... 5 luxe features include: un ique uBlend" control Amer ican Electronics, I nc., American for continuously variable channel separation Concertone Division ...... 67 from full monaural to full stereo, 4-position Amperex Electronic Corp...... 65 Selector, Mode, Loudness and Phase switches. Ampex Co rporation ...... 29, 51 Also provided are outputs for 4, 8 and 16 ohm Apparatus Development Corporation . ... 75 speakers. Hum-free operation is insured by the Audax Di vision, Rek-O-Kut Co., Inc . .. . 45 use of DC on all preamp and tone control tubes. Audio Bookshelf ...... 72 Harmonic distortion, less than 0.25%' 1M distor Audio Empire, Precision Products of tion, less than .5%' Hum and noise, 74 db below Dyna-Empire. Inc ...... 71 full output. D.sign.d with the kit builder in Audio Exchange. Inc ...... 75 mind, assem bly is simple-no special skills or Audio Fidel ity Records ...... • . .. 49 tools required. Complete with deluxe cabinet and Audiogersh Corp ...... •...... 58 legs, all parts, tubes and detailed instruction Audion ...... _ •. . .. _ ... . 75 manual. Shpg. Wt., 26 Ibs . Audio Unlimited ...... 75 KT-2'OA Stereo Amplifier Kit ...... 5.00 Down Net 74.50 LA-250A Ster.o Amplifi.r, wir.d ...... 5 .00 Down Be ll Sound Di vision, Thomson Ramo Net 99.50 Wooldridge, Inc ...... 52 Bell Telephone Laboratories ...... 18 Bogen-Presto ...... 43 Bozak ...... 50 KT -500 FM-AM Bradford Audio Corporation ...... 12 Brand Products Inc...... _ . .. 57 STEREO TUNER KIT British I ndustries Corporation ...... 3 Classified ...... 74 More than a year of research, planning and en gineering went into the making of the lafayette Stereo Tuner. FM specifications indude grounded Duotone ...... _ ...... 70 grid triode low noise front end with triode mixer, Dynaco, Inc. 6 1 double-tuned dual limiters with Foster-Seeley dis criminator, less than 1 % harmonic distortion, full EICO ...... •. . .. 15 200 kc bandwidth and sensitivity of 2 microvolts El ectrodyne Corporation ...... 68 for 30 db quieting with full limiting at on. mi El ectro-Sonic Laborat ories. Inc...... 69 crovolt. El ectro-Voice. Inc ...... 37 The AM and FM sections have separate 3-gang tuning condenser, separate flywheel tuning and Electro-Voice Sound Systems. Inc ...... 75 separate vo lume control. Automatic frequency control \\Iocks inti FM signal permaneJ).tly. Two: Fisher Radio Corp...... 35 separate printed circuit boards make construction Fukuin Electric (Pioneer) ...... 11 and wiring si mple. Complete kit includes all parts Fukuyo Sound Co .• Ltd. (Coral) ...... 58 and metal cover, a step-by-step instruction man ual, schematic and pictorial diagrams. Size is 13'.4" W )( 10'/." D x 4%" H. Shpg. wt., 22 fbs. General Electric ...... 39 KT-500 ...... 5.00 Down ...... Net 74.50 Glaser-Steers Corporation ...... 55 LT-50. Same a s above. complete ly factory wired Gotham Audio Sales Co .. Inc ...... Cov. II I and t.st.d ...... 5.00 Down, ...... N.t 124.50 Grado Laboratories, Inc...... 64 Heat~ Company ...... •.... . _ . . . .. 7 -9 . .KT ~600 PROFESSION~L ' Key Electronics ...... 7 5 Kierulff Sound Corporation ...... 75 STEREO CONTROL CENTER KLH Research & Development Corp. .... 59 Solves Every Stereo/Monaural Lafayette Rad io ...... 76 Control Problem! Lansing. James B., Sound, Inc. .... Cov. IV Provides such unusual features as a Bridge Con trol, . for variable cross- channel signal feed foe Neat Onko Denki I Tannoy ...... •• ...... 66 I o Send FRE.E 308 GIANT SIZED PAGE Catalog 600 I Uher ...... 33 CUT OUT I University Loudspeakers, Inc...... 56 Name _....•...... •••..• _...... •• .• •. •• AND I PASTE ON I Viking of Minneapolis ...... 31 I Address •.•.•••.••••••• '.' • • • • • • • • • • • • • • • • • • • • • • . • POSTCARD I Weiss, Warren ...... • ...... 33 ;'-:ity ':'':.::.:.. :~' ~':':" ..!~:..:.: :!~e:.:.::.:.:..:.: :..:.: ::.:. ______I 76 AUDIO • MA'RCH, 1960 ~ ~~~ ~~~~~~~--~==~~~~_~_~EZti~~. ~~~~~'~UE~~WWX~_~W~_~~~.. ~, .~·mQ~£~"~~ im.~'~. ~;4~*~J~#e'_~Q~. s~.. ~JS ~" ~ , The TEe S-15 all transistor 40 watt stereo amplifier brings a space age concept to high fidelity. Never before has the audiophile been able to get so much high quality sound for so little. A neat package 10" long and seven pounds light puts out 40 watts of pure undistorted sound. And the price is as exciting as the package-only $129.50. Because of its all·transistor circuitry, the unique S-15 has no heat, no hum, no microphonics. Quite naturally, from Transis-Tronics. Write for your copy of complete specifications. Power Output 40 wiltts (20 watts per channel). Frequency Response ±0.5 db 20-20',000 cps. Response is 3 db down at 6 cps and 45,000 cps. Intermodulation Distortion less . , than 0.9 % at rated output, 60 and 6000 cps. Harmonic Distortion less than 0.5 % at rated levels. Inputs 5 pair: magnetic phono, t uner, tape, au xiliary 1, auxiliary 2. Front Panel Controls: volume, power; balance; bass channel A; bass channel B; treble channel A; treble channel B; function (phono; tuner, tape, auxiliary 1, auxiliary 2); mode (mono A, stereo, mono B); loudness; scratch filter, rumble filter. Balance Control for TEe equalizing speaker outputs. At full rotation will completely cut off sound f rom either speaker. Circuitry, 2 germanium diodes, 3 silicon diodes. Power Requirements 105-120 volts AC, 50-60 cps; 12-28 volts DC for battery operation. S-15 TEC Transistor Engineered Components I E I ~~ ______1-_~ ___~ ______....: T.:.:£e:..:'::..S.:.:TH::..£.:.:'R:.:'O=£H"K 0' 'RANS'S,,,ON,es. 'He . Tmnsis-Tronics, Inc., 1601 Olympic Boulevard, Santa Monica, California