John Mullin and Murdo McKenzie 1947, from High Fidelity 3/73

Ranger tape recorder ca. 1950, from AES Journal, June 1989

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Major John T. Mullin brought the Magnetophone to America at the end of the war. He was an electrical engineer in the Signal Corps assigned to investigate radar interference in Britain. As he listened to hours of music broadcast from Germany each night, he wondered how full orchestras could be playing symphonies at all hours of the night. The quality was equal to live radio, and was better than shellac records. On a trip to Radio Frankfurt he discovered the secret: Magnetophones with ac biasing. He studied the circuitry of these machines, and sent 2 old machines with dc biasing home to San Francisco with 50 reels of BASF Type L tape. He modified the electronics of the old machines to add dc biasing and demonstrated them May 16, 1946, to the Institute of Radio Engineers in San Francisco. Harold Lindsay heard this demonstration and told Mullin about the Ampex Corporation that had been founded by Alexander Matthew Poniatoff in 1944 (the name came from his initials plus "ex" to avoid using the same name AMP already taken by the Aircraft Marine Products company). Ampex Electrical and Manufacturing Company built high quality motors and generators that used Alnico 5 magnets from the GE, but with the war ended Poniatoff was looking for a new product. Mullin provided Ampex with some information about his Magnetophone but was also supplying information to Col. Richard Ranger in New Jersey who was developing his own tape recorder. Ampex used the FIAT reports of the U.S. Government Intelligence Agency Reports on German industries to gain more information to develop its own tape recorder design.