THE BIRTH OF TAPE RECORDING IN THE U.S. Peter Hammar Arnpex Museum of Magnetic Recording Redwood City, California Presented at the 72nd Convention 1982 Oct~ber23-27 Anaheim, California This preprint has been reproduced from the author's advance manuscript, without editing, corrections or consideration by the Review Board. The A ES takes no responsibility for the contents. Additionalpreprints may be obtained by sending request and remittance to the Audio Engineering Society, 60 East 42nd Street, New York, New York 10165 USA. AI1 rights resenled. Reproduction of this preprint, or any portion thereof, is not permitted without direct permission frorn the Journal of the Audio Engineering Society. AN AUDlO ENGINEERING SOCIETY PREPRINT The Birth of Tape Recordlng rn the 1J.S. by Peter Hammar, Curator Ampex Museum of Ma~netlcRecording Redwood City, CA In 1945 when Major Jack Mullin, U.S.A. S~gnalCorps, came home to San Franclsco w~thtwo German Magnetophon audio tape recorders, he had no idea he and three other Bay Area engineers, Bi11 Palmer, Harold Lindsay, and Myron Stolaroff--not big companies llke GE, RCA, or Westinghouse--would be the ones to revolutionlze Amerlcan record~ng. By 1947, tlny Ampex Corporatlon surprised U.S. studios and broadcasters w~ththe flrst successful American Version of the tape recorder. How were Arnpex's Lindsay and Stolaroff able to bu~lda hi-fi tape machlne while others failed7 [This article 1s dedicated to the late Harold W. Llndsay, AES member and aud~oploneer, the designer o€ America's flrst successful professional audio tape recorder. Harold's hlgh englneerlng Standards and personal regard for hls fellow man made him a friend of us all. We miss him very much.1 In 1982 ~t LS easy for us to take magnellc tape recording for yranted. Many mrmbers of this Soc~etyweren't even horn when American englneers set postwar magnetic recording stand- dards that are still followed today. In professional audio recordlng in the {J.S., the leap from no tape Ln 1947 to an lndustry dominated hy magnetlc record~ngIn 1949 was unparalleled In modern technolog~cal history. Hy the end of World War 11, magnetlc recordlng was nothlng new Ln Amer~ca. We had had wire recording here as early as 1903, wh~n a Danish electrlcian, Valdemar Poulsen, founded the Ameri can Telegraphone Company. By 1900, Poulsen had already become the "Ed~son"of magnetic recordlng, lnventing almost every known form of electro-magnet~c storage, uslng wir^ 111 varlous forms: solld steel tape, and meta1 d~scs. Poulscn's Telegraphone r~corders met with publlc accla~m,followed by repeated marketing faijures. Except for occasional research by Lee DeForest (the lnventor of the vacuum tube) and the U.S. Navy, magnetlc recording in the U.S. lay dormant until. 1939, when a young engineer~ng student in Chlcago named Marv~nCamras built an experimental wlre recorder. TJnt~l '39, al1 wlre recorders In thl~scountry used DC blas In the record c1rcui.t to reduce distort2on and In- crease dynam~crange. Whlle recordlng tones on h~srecorder WI.th a signal generator one day, Camras di scovered that a high frequency AC SI-gnalsuperlmposed over the recorded slgnal dramatically ~mproved slgnal-to-nolse rat1.o and dlstort~.on. In America, Camras became bhe first engineer slnce Poulsen to make serlous advances in magnetic record~ng. Distributed under license from the Armour Research Institute In Ch~cago, Camras' magnetlc wire recordlng patents led to the extensive use of wlre by the Allied Forces during World War 11. For all its wartime successes, however, many American audlo englneers looked at magnetic recording as a dictatlon device at best, not suited to professlonal record~ng. The 1945-46 postwar prejudlce agalnst magnetlc recording as a professional audio medium was somewhat strengthened by the ~ntroductlonby Cteveland's Brush Development Company of Amerlca's flrst tape recorder, the Brush BK-401 "Soundmirror". l'he BK-401 was remarkable In that the machlne attempted to use what was, for Amerlca, a new technology, although Hrush englneers encountered many unforeseen problems mak~nggood heads, a stable transport, and good electronlcs. The BK-401 incorporated Marvin Camras' AC-bias clrcuit. Using paper tape coated wlth black oxide, the consumer-or~ented BK-401 fell short of professional audio sLüridards of Ltie day. 3M's 1.946 ~iitroductionof the~rflrst magnetic tape roduct, "Scotch No. 100", made for the BK-401, provided the CF. Faul company with a head start Ln tape research and developrnent. Ry the next year, when Jack Mullin and Arnpex requested tape samples wlth lmproved oxides, 3M was ready. Thelr famous "Scotch 111" and "11.2" were the result. In Europe duri~ng the 1930s, englneers had been viewlng magnetic recording in an cntirely di fferent li~ght. Ac 1.n the [].C., early attempts at wlre development had falled rn both Germany and England. Ry 1934, however, the Lorenz Company (now part of ITT) had perfected a magnetlc recorder lt called the "Stahltonmasch~ne" or "steel sound machlne" that used a flexible, solid steel tape as the storage medium. With the Lorenz Stahltonmasch~ne,magnetic record~ngin Europe had graduated from an engineer~ngcuriosity to posslble pro- fesslonal acceptance. Total acceptance, however, first ln Germany and then ln America, was to come wlth the devel-opment of hlgh- fldellty recorders using magnetically coated tape. In the late 1920s, Frltz Pfleumer, a German mechanical engineer who was also an audioph~le,built the world's first working prototype tape recorder. Uslng paper strips Lhat he coated with carbonyl iron particles suspended In lacquer, Pfleumer bullt a tape machine that was good enough Lo con- vlnce AEG-Telefunken Ln Berlln (the Cerman General Electric) that tape recording had a future. Working with the glant ßASF/I.C. Farben chemical concern In 1936, the AEG englneers marlceted thei r new recorder under the name "Magnetophon" or "magnetic phonograph". By 1938, the AEG Magnetophon was advanced enough to have three of the four necessary components of modern professional tape record~ng: 1) a stable transport, 2)good tape created at BASF, and 3) the ring head for ersse, record, and playback, developed by AEG's Eduard Schweller, a head that closely resembles most OE roday's heads. The fourth elemant of hi-fi tape recording, gaod e1ectronics using AC blas in the record circuit, would have to wait until after ehe start of the Second World War. And eherein. lies one OE the biggest industrfal espionage mysteries of this century. By 1932, a year before Hitler came to power, German radLo stations were using relativcly high-quality wax and lacquer discs to transcsibe programs for delayed broadcast. By 1936, three years after the decreed unffication of srations lnto a singLe necwork bascd in Berlin (and called the Reichs-Rund- funk-Gesellschaft, or RRG), Germany was interconnected by a seriec of high-quality underground 10 kiiz audLo lines (600 ahm balnnced, aith lcss than L dB loss over 1000 km). Keep thls fact in mLnd later, when we gec ta Hitler's speeches recorded on t he Magnetophon. In 1938, the chief engineer of Reichs-Rundfunk, H.J. von Rraunrnuehl, adopced magnetic tape as the Euturc standard for broadcast: recordlng in Gerrnany. Von BraunrnuehL wanted ta replace che cumbersome transcription discs thcn in use, and was canvinced thar the DG-bias Magnetophon could be impsoved for on-air use. Ry 1941, two years after the start of World War 11, alL Gerrnan radio stntiona were equipped with high-fideLLEy ronsole AEG Magnetophon tepe recorders, the so-called "HTS" Version based on the L939 "K-4'' rnodel. Hi-fi tape had cmne about: Ln 1939-40 when Walter Weber of the RRG bad, lrke Marvin Camras Ln Chicago the same year, accidentaily discovered that an AC-bias current in the record ctrcuit improved quallry. DC-biae K-4 Magnetophons had limited specifications, wich a Frequency sesponse of only 50 Hz so 6 kHz, 5 percent distortion and a dynamic range of 40 dR. Weber's AC-bias circuit improved the I<-& to 40 Hz ta 15 kHa, 65 dB dynamic range and only 3% dlstortion. Naturally, the hi-fi Magnetophon quickly replaced the trsnscript.Lon discs at all German radio stations. 1941 was the year German broadcacting put the ~C-bms AEG Magnetophon an the air regularly, coupled with routine day and night interconnects among ehe stations oE ehe RRG. From Ramberg Ca Bremen, Erom Rerlfn Co Breslau, broadcasts could originate at ane place and trancmit from another. The Rerfin Phllharmontc bcgan regular recording sessions Eor 24-hour use on the air. Ry wartime, over 95% OE BRG programming originated in Berlin. Occasionally, Capes were scnt to indi- vidual. stations for later broadcasc. Occupied Europe and Africa, not cunnecLed ta the RRG net, received much programming via Magnetophon rape. High-Fidellcy tape recordings af che Berlln Philharmonie made bctween 1941 and L945 that Deutsche Grammophon/ Polydor rccently di.scovered in Cniso gor there through RRC tape "bicyclLng", the earllest tapc network. AL the BRG Ln Berlin during the war, a typfcal bsoedcasr day would include both live and taped speeches by Nazi oEEicials, intersparsed with taped rnusic and commentary. The tape recorder had added a flcxibility to broadcastlng that would nor reach American radio until almost ten years later, in 1948-49. In 1981, just 40 years after the start OE hl-fk tape on German radio, I told several retfted RRG engineers about the postwar Allied belref that ltthe Nazis ordered the Magnetophon Co be devcloped in order to £001 the Allies es to the exact whereabouts of HitZcr whLle he made live-sounding speeches s~multancouslyin severnl different locatians".