Stanford Libraries' Ampex Model 200A Magnetic Tape Recorder, Restored by Larry Miller

On 2012 November 13, the Stanford Libraries held a reception to celebrate Larry Miller's restoration of their Ampex Model 200A Magnetic Tape Recorder, that is now on public display in the Cecil H. Green Library, East Wing, Information Center (1st Floor), at Stanford University.
Larry gave a short talk acknowledging the help he had received in the doing the restoration, and describing the importance of the Model 200A. Then John Leslie spoke of the early days of Ampex.

The Ampex Model 200A was originally described in an 8 page brochure that described its advantages, and gave its specifications.

The Ampex 200A, derived from the German "Magnetophon", was designed by Harold Lindsay and Myron Stolaroff. The recorder/reproducer came with an Instruction Book describing its specifications, operation, and maintenance. It specifies "TAPE: Sufficient reserve capacity and flexibility have been designed into the amplifiers so that any of the leading makes of tape [available in 1948] may be accommodated. However, as shipped the machine has been specifically set up for the use of Minnesota Mining & Mfg. Co.Type RR tape". 3M also called the Type RR tape "Type 112". The other tape that was often used was 3M Type 111. Del Eilers (ex-3M) has summarized the technical specifications of the Types 111 and 112 (and other 3M types). There is also a 3M "Sound Talk Bulletin" B15: The Use of No. 111 Sound Recording Tape on Machines Designed for No.112 Tape, undated"

Most of the Model 200A recorders were converted to the Model 201, so you are unlikely to find an unmodified 200A in the field. The 201 uses a very different equalization curve.

Most of the recordings from the 200A were erased and the tape was re-used, so you are unlikely to find any original recordings. That's an unintended consequence of making a recorder with a re-usable medium. If you should have such tapes, play them at 30 in/s with the "IEC1" equalization for 30 in/s. Please tell us if you find any original recordings made on an Ampex 200A. You can identify them because they use a 60 kHz bias frequency.

J. McKnight, 2012-12-10 rev --14

AES - Audio Engineering Society