Audio Magazine February 1961
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I ~ ' - , - New RCA complements of IOO-milliampere heater tubes for 120-volt series- heater complement, bring important sales advantages to your ac-dc radio and phonograph designs. Slimmer, smaller cabinets-greatly reduced with cooler operation and better acoustic NEW 100-MA HEATER TUBE COMPLEMENTS heat-longer life expectancy-high operating response); lessens possibility of cabinet 5-Tube Radio Complement 18FX6, IRFW6. 18FY6. 34GDS. and efficiency! warping or discoloration; allows wider 36AM3-A. Performa nce equals ISO-MA Now you can design these sales advantages choice of cabinet materials; and lends new heater lube complemenlS' Yet 100-MA flexibility to positioning of parts and printed complement dissipates much less heat. into ac-dc home radio and stereo, thanks to 4-Tube Economy Radio Complement a new series of RCA tube complements de circuit boards. And important to you-these 18FX6, 20EQ7, SOFKS. 36AM3·A. To p veloped for 120-volts, 1 DO-milliampere 100-milliampere heater tube complements performance for a 4-tube complement. series-heater operation. These are the first provide performance equal to that of a 150- 2-Tube Stereo Complement Two 60FXS's can provide 1.3 watts out kits of 1DO-milliampere tubes whose heater milliampere heater tube complement; put per channel using a I,igh-outpul voltages add up to 120 volts, the normal furthermore little or no modification is re stereo cartridge. value of power supply that RCA considers quired in your basic circuit design. 3-Tube Stereo Complement 20EZ7, two SOFK S's. 20EZ7 permits usc available in most American homes. Get full details on these new 100-milli of stereo cartridges w ith moderate output. With these new tube kits, temperature of ampere heater tubes! Check with your RCA 4-Tube Stereo Complement cabinet hot-spots has been cut 15-25 %. This Field Representative, or write: Commercial 36AM3-A, 20EZ7, two 34GDS's. Capa· ble of delivering 1.4 watts per channel decrease in temperature permits reduction Engineering, RCA Electron Tube Division, with a B+ supply voltage of 110 volts. of cabinet size (or retention of present size Harrison, N. J. RCA FIELD OFFIC ES EA ST : 744 Brood St., Newark 2, N. J . HU 5-3900. MIDW EST: Su;te 1154, Me r· chandise Mart Plaza, Ch icago 54, Illinois, WH 4-2900. WEST: 6355 East Wash;ngton ..Th, Mo" T,.."d N,m, in EI,"mni£, Blvd. , los Angeles 22, coni. RA 3·8361. RADIO CORPORATION OF AMERICA ® FEBRUARY, 1961 VOL. 45, No. 2 S.22OO FM/ AM / MX Stereo Tuner-$179.50 Successor to RADIO, E st: 1917. S-5OOOD Stereo Dual Amplifier-Preamp. 80 Wat~ music po~er ~~l~. _~~ ENGINEERING M USIC SOUND R1: PRODUCTION C. G. McProud, Editor and Publisher Henry A. Schober, Business Manager $.2200 - $·3000 m - Sherwood tuners have consistently won outstanding honors from David Saslaw, Managing Editor most recognized testing organizations. They Janet M. Durgin, Production Manager feature 0.9!\Uv sensitivity, Interchannel Hush noise muting system, "Acro·Beam" tuning Edgar E. Newman, Circulation Director eye. cascode balanced input. automatic fre· quency control. and on the S·3000 m. "Iocal distant" switch, "Corrective" inverse feedback. 5·5000 II-' 'The Sherwood S·5000 •.. shows no Sanford L. Cahn, Advertising Director compromise or corner·cutting in design or construction."-HIGH FIDELITY MAGAZINE. West Coast Representative- The Sherwood S-5000 was highest rated by the lames C. Galloway American Audio Institute (and other testing 6535 Wilshire Boulevard, Los Angeles 48, Calif. agencies) . now even better. the S·5000 II has 80 watts music power, scratch and rum· Midwestern Representative- ble filter effective on all inputs. Plus Single/ Dual Bass and Treble Controls. Mid·Range Bill Pattis ~ Associates Presence Rise. Stereo·Mono Function Indicator 6316 N. Lincoln Ave., Chicagl!- 45, Ill. Lights. Phase·Reverse Switch, and Damping Factor Selector. 5·5500-Same as 5·5000 n except 50 watts CONTENTS music power, no presence rise. $159.50. Audioclinic-Jo seph Giovanelli 2 New modular component furniture-The serio Letters 6 ous hi·fi enthusiast will appreciate Sherwood's Light Listening-Chestet· Santon 8 new cabinetry in fine hand-rubbed walnut. Sherwood also makes FM Multiplex Adapters Audio ETC-E dw(M'd Tatnall Canby 12 and Crossover Networks as well as these out· Editor's Review ..... .......... ................ 16 standing Monophonic units: S·2000 n FM/ AM Tuner $145 .00 . S·1000 IT "Music Center" A Case for the Custom Console-F. H. J ac kson 18 Amplifier·Preamp. 36 watts $109.50. "Ersatz Stereo" Unlimited-C. H. lJilalmstedt 20 Sherwood Electronic Laboratories. Inc., 4300 Computers in Audio Design-R. G. B uscher-In Two Pa1·ts-Pa1·t One 22 N. California Ave •• Chicago 18, Illinois. Characteristics of Tape Noise-William B . Snow 26 Tape Guide-Understanding the Tape Oscillator-He1'man BU1'stein and H em'y C. Pollak · .... 28 Loudspeaker Design-N01 'man H. Crowhu1'st .... .. ............. 36 Equipment Profile-Sargent-Rayment S R -8000 tune1'-p1'eamp and S R-202 Rev e rb e mti01~ unit-Shure S tudio Dynetic stet'eo m'm and cart1'idg e F ai1'child 440 t U 1"1~ t a bl e-H . H. S cott LT-10 FM tune1' kit- Ercona N01"Cli c loudspealcer ........ .. 48 Record Revue-Edwa1'd T atnall Canby .... ....... .................................................. .. 60 About Music-Harold Law1'ence .... ..................... ......... .. .............. .... ..... .. .......... ... 66 J azz and All That-Charles A. Robet·tson 68 New Products 74 Modular Component Furniture New Literature 77 Industry Notes 87 Advertising Index 88 COVER PHOTO-Room-divider or wall-type decorator units serve as mounting for hi-fi equipment. An exclusive creation of Allied Radio Corporation, Chicago, the line of basic units includes an equipment or record cabinet, shelves and shelf backguards, and a speaker enclosure which will accept any 12- or 8-in. speaker and still provide for 30 to 50 LP r ecords. Finish is oiled walnut veneer, with free-standing satin brass poles drilled every six inches f or complete fl exibility in assembling-and only a screwdriver is needed. AUDIO (title registered U.S. Pat. Off: ) is published monthly by Radio Magazines. Inc. • Henry A. Schober, President; C. O. McProud, Secretary. Executive and Editorial OIDces, 204 Front St., Mineola, N. Y. Subscription rates - U. S. Possessions, Canada, and Mexico, $4 00 for one year. $7.00 for two years, all other countries, $5.00 per year. Single copies 50¢. Printed In U.S.A. at 10 McGovern Ave., Lancaster, Pa. All rl gbts reserved. Entire contents copyrigbted 1961 by Radio Magazines, Inc. Second Class postage paid at Lancaster. PI. RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y. Postmastet·: Send FOl'm 3579 to AUDIO, P. O. Box 629, Mineola, N. Y. for brochure write Dept. A·2 . AUDIO • FEBRUARY, 1961 AUO IOclinic STABLE ROTATION GIVES YO U JOSEPH GIOVANELLI ';' Head Wear the best he can do is to give yon an ap REAL Q. Quite otten we see tape head man1t· proximation. If one head specifies 100 hours tacfu1'e1's incl1ule among the'ir specifications of life and another one 1000 hours you an esti?nated lite tor thei1' heads. For in can guess with some certainty that the lat· stance, one Viking head has a ?1tini1num tel' head is a better head from the life SATISFACTION !-ite of 1000 hours acconl'ing to the com· expectancy standpoint than the former. We pany. Si?1.c e no tape speed is specified, isn't cannot know, of course, whether this ap· th'is statement incomplete?, It we think of plies to all other performance data for the the wea?'ing prope?·ties ot 1'ec01'cling tape as head. consisting of so many "gl-itS per i?fph" ot weal' at the heaels, then at 3.75 ips it' would To Play 78's take twic!:: as long to Ca1tSe a given amount Q. I have, in addition to my regular ot weal' than at 7.5 ips. I s this true, or· rec01'd collections, several dozen old 78- have I ovel'looked s01nething? Dick Dun· rpm Tecol'ds elating [l'om the early 30's. ham, Memphis, Tennessee. I am planning ·to tape the best ot these. NEAT A. The data for the life expectancy of a I wmtld like to know the best 1nethod ot Professional 4 speed turntable wi th tape playback or record head must, of ne· gett'ing them on the tape. I s it wise to play cessity, be incomplete. The manufacturer the recoTds with a l·mil or a 0.7-mil stylus cannot know the speed with which the in ordm' to get below the wont areas in the head is to be associated and hence, the num· Groove? John Wawzone7c, Cumberland, bel' of abrasive particles which will pass Rhode I sland. P':'68'H over it. Also, he do es not lmow what tape A. To begin with, I do not recommend tensions and pressures the head will be sub· that you play your old 78's with a I-mil j ected to. or a 0.7-mil stylus. Either of these styli I would say that tensions and prcs3ures will sink to the bottom of the groove and are more likely to contribnte to t he varia will cut into the shellac, resulting in stylus tions in head life than will the possi.ble damage and causing considerable noise in variations in tape speed. There is, of reproduction. FUI:t\ler, the narrow stylns course, no doubt that the f aster tape travel, will flop around ~: the grooves, leading to the faster the head will wear.