~r---~----~~----~~~--------~--~--__ MARCH,. 1962 SO¢ www.americanradiohistory.comAmericanRadioHistory.Com COOLNESS OF TRANSISTORS ­ WHAT MAJOR COMPONENTS AR E NEW CIRCUITRY, PRECISION OF FRAME GRID TUBES I NCLUDED I N THE NEW "ASTRO"? NEW FEATURES, For cool operation, Altec makes judicious Five integrated stereo components are use of transistors. For highest sensitivity packaged in a compact 6" x 15" x 131;2" and quietest performance imaginable, new cabinet: FM, FM multiplex, AM, dual­ NEW IDEA IN STEREO channel preamplifiers, dual-channel power ultra-precise frame grid tubes are used. amplifiers. The wide band FM tuner fea­ "Modern" is not the word. Perhaps This proper combination of transistors and tures 1.5 microvolt sensitivity (equivalent "ahead-of-its-time" is a bit more descrip­ tubes in the "Astro" has produced results to 0.75 microvolts with matched 72 ohm that are just this side of miraculous. antenna) to assure highest gain, lowest tive of the new Altec 708A "Astro." How noise. A built-in FM stereo multiplex re­ else would you describe an all-in-one ceiver provides 30 db stereo separ.ation be­ stereo center full of features and facilities The "Astro" is sensitive, stable and com­ tween channels over the entire audio never before available in a single package? pletely consistent in its performance (top­ range. To take all guesswork out of tuning, a monitor light goes on automatically notch!) and utterly free of drift. Indeed, it when stereo signal is received. The AM For example, consider its circuitry. is the first truly practical stereo center be­ tuner provides high sensitivity and excel­ Transistors are combined with new frame cause transistors in the power stage make lent image and IF rejection. grid tubes to gain the best qualities of each. it run cool for hours on end. Unlike ordin­ The preamplifier section features a com­ As another example, consider its unique ary "hot boxes," the "Astro" secures peak plete complement of controls and includes stereo headphone facilities. The output re­ operating efficiency and maximum life facilities for everything from record and tape player to the stereo headphones. ceptacle is in the rear; you may leave the from resistors, capacitors, and other sub­ Powerful dual-channel amplifiers deliver headphones plugged in permanently, out components in its circuitry. And, because 25 watts each down to 20 cycles (lHFM of sight when not in use. The headphone it runs cool, the "Astro" is the first practi­ standard) with ± 1 db, 20-20,000 cps fre­ switch, however, is located conveniently cal unit for built-in installations. quency response. on .:le front panel. YOU MUST SEE & HEAR THE "ASTRO" Feel it, too, for that all-important cool­ Or, consider the unique tape recording ness. At your Altec Distributor's now. Or, 50 watts from monitor that functions much like monitors for information, write Dept. A3 an area the size in professional recording studios. Namely, of a postcard! it permits you to monitor any source © 1962 ALlEe LANSING CORP. material two ways during recording: the That's the magic A Subsidia71l instant signal enters the record head or of transistors: 1... of Ling-Temco- directly from tape, the moment it is re­ the four shown LJ!'J.~~~iiiii~1 Vought. Inc. corded. And these features are only a at left make up sampling. Truly, the "Astro" is "ahead-of­ the power stage its-time" even down to the smallest details of the "Astro." ALTEC LANSING such as the exclusive friction-lock controls In all, 12 transistors and 17 tubes are used CORPORATION that obsolete awkward dual knobs found in this entirely new stereo center that is 1515 S. Manchester Ave .• Anaheim, California on conventional stereo equipment. rated several years ahead of its time. 161 Sixth Avenue. New York }3 •. New York www.americanradiohistory.comAmericanRadioHistory.Com l\1t.RCTI, 1962 Vol. 46, No. 3 Successor to R.AmQ , Est. 1917 C. G . MCPROUD • Publisher DO YOU D AVID SASLAW Editor LIVE NEAR ONE OF JANET M. DURGIN Production Manager THESE " - ' . ' . '"' .. ' ~-:- . : -, ' '-:'::':' STEREO·FM Contributing Editors CITIES? E DWARD TATNALL CANBY HENRY A. SCHOBER Representatives Business Manager & JOSEPH GIOVANELLI Ariz.: Phoenix : KEPI , KNIX Bill Pattis Associates, Calif., Fresno : KCI B, KXQR 4761 West Touhy Ave., H AROLD L AWRENCE los An~eles : KFMU, KMlA SANFORD L. CAHN OceanSIde: KUDE Lincolnwood 46, Ill. Sacramento : KSFM Advertising Director CHARLES A. ROBERTSON Santa Barbara : KMUZ James.c. Galloway, San Diego: KGB , KlRO, KPRI CHESTER SANTON San Francisco : KPEN, KBAY EDGAR E. NEWMAN 6535 Wilshire Blvd., San Jose: KSJO Circulation Director Los Angeles 48, Calif. H ERMAN BURSTEIN Visalia: KONG Woodland: KATT Conn., Newton: WGHF Dela ., Wilmington: WJ BR Fla ., Miami Beach: WAEZ, WVCG Orlando: WHOO AUDIO Articles Sarasota : WY AK . Ga., Columbus : WRBl III., Chicago : WEFM, WFMT, WKFM A High Quality Stereophonic Mixer J 9 Robert Gerbracht Rock Island : WHBF Ind., Evansville: WIKY The Frequency-Response Specification 24 Mannie H orowitz Indianapolis: WFMS, WISH Iowa , Des Moines : KDMI Electronic Organ Tone Generators- In Two Kans. , lawrence: KANU Wichita: KCM B Parts- Part II 30 D. Wolkov Md., Towson : WAQE Mass., Boston (Waltham) : WCRB lynn: WUPY Mich ., Detroit : WDTM, WGPR AUDIO Reviews East lansing : WSWM Grand Rapid s: WJEF, WOOD Minn., Minneapolis: WAYl, KWFM Light Listening 8 Chester Santon Mo., Kansas City : KCMO Sl. louis: KCFM, KSHE, KWIX Record ReVUe 46 Edward T atnall Canby Nebr., Omaha : KQAl Nev., las Vegas : KORK Jazz and All That 54 Charles A . Robertson N.J., Dover : WDHA long Branch : WRlB N.Y., Garden City: WliR New York: WQXR, WTFM AUDlO~ Profiles . Schenectady : WGFM Syracuse: WSYR Westbury : WGFM Fisher Stereo Control Amplifi er Kit 40 K X -200 N.C., Burlington : WBBB Ohio, Akron : WDBN Fisher FM-Stereo Tuner Kit 40 K M-60 Cleveland: WNOB Columbus: WBNS Heath Oscilloscope 43 M odel 10-21 Middletown : WPFB Ore., Eugene: KFMY Omega Transistorized Stereo Amplifier 44 Model 1600 Portland : KPFM Penn., Johnstown : WJAC H. H. Scott Speaker System 44 S-3 Norristown : WIFI Philadelphia: WFlN, WHAT, WQAl Wilkes-Barre: WYZZ R.I., Providence : WPFM AUDIO in General S.C., Spartanburg: WSPA Texas, Dallas: KIXl, KSFM Hou ston: KODA, KFMK, KGHM Audioclinic 2 Joseph Giovanelli Wichita Falls: KNTO Va ., Richmond : WFMV Letters 6 Wash ., Seattle: KISW, KlSN Wi se., Milwaukee: WFMR, WMKE, WTMJ Audio ETC J2 Edward T atnall Canby Canada, Oshawa : CKlB Editor's Review J6 Toronto: CFRB, CHFI Tape Guide 34 H erman Burstein Audio Teasers 38 N orman H . Crowhurst New Products 60 This Month's Cover 65 If so, see your Sherwood dealer right away! The FM stations listed above About Music 66 Harold Lawrence are now-or soon will be-broadcasting Industry Notes 7J in Stereo. To enjoy fully this thrilling new experience, you need the Advertising Index 72 incomparable Sherwood S-8000 FM·Stereo Receiver and a pair of Sherwood SR3 "Ravinia" Loudspeakers . See and hear these superb stereo ·MEMBER· starters at your Sherwood dealer. "'SlIfUU Of Sherwood Electronic laboratories, Inc., ,"0' "",wo •. • '"' " .J • ,",- ..... ~ ......... 4300 N. California Ave ., Chicago 18, $M -;. '"".zines, Inc., Henry A. Scbober, President; C. O. McProud, Secretary. Executi •• Illinois. For details, write Dept. A·3. it ~ and Editortal OMces, 204 Front St., Mineola, N. Y. Subscription rates-U. S., ~ c: Possesaions, Canada, and Mexico, $4.00 ror one year, $7.00 ror two yeor8; all ~_ <.... ~ other countries $5.00 per year. Single copies 50¢. Printed in U.S.A. at 10 ., -;" MeGoTern Ave., Lancaster, Pa. All rights reserved. Entire contents eopyrlghted 'INC ' 1962 by Radio Magazines, Inc. Seeond Class postage paid at Lanca,ter, Po. SHERWOOD .. RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y. only for those who want the ultimate Postmaster: Send Form 3579 to AUDIO, P.O. Box 629, Mineola, N. Y. AUDIO • MARCH, 1962 www.americanradiohistory.comAmericanRadioHistory.Com AUOIOclinic ,• W IDE i • BAND • microphones • for JOSEPH GIOVANELLI"" ~ STEREO and Interna l Circu it Grounding to bring my filament grounds directly to the MONO main ground-to the chassis-so that they Q. I would welcome information on the won't cause hum voltage to be introduced following question. In reading articles in along the length of the bus bar. It would AUDIO and other magazines, there appears be a good idea to return the B filter ca· g~ to be two schools of thought in regard to pacitor leads to this same, main ground ~ grounding of amplifiers. Both schools agl'ee point. The centertap of the power trans­ -~ ' that the internal circuit ground should be former is returned here also. These are .., .., professional made to the chassis at one point only, some of the most important considerations o usually at the input jack. One school uses in grounding circuit elements within an -- regular hookup wire to run separate wires amplifier. By observing these precautions, - qua Iity from each component to the single ground you can produce virtually hum-free per­ point. The other school uses a single, heavy formance from your preamplifiers, provid­ ~:J for the gl'ound bus, grounded at one point and ing that care is taken in filtering of Band run through the amplifiel' with the ground filament supplies, and that hum is not ~ studio and points tied on to it. It appears that the picked in the input devices such as tape :t- order of the grounding points on this bus playback heads or phono cartridges. the audio is critical. My question is in two parts,' When using the hookup-wire system you 1. Is either method superior to the other? do not need to run a wire from each in· 2. In the ground bus method what order of dividual component to the main chassis perfection ist grounding to the bus would be best for a ground.