Ampex 351 Stereo Studio Tape Recorder

Elvis Presley, Johnny Cash, and Jerry Lee Lewis shared sessions with unreleased recordings from material recorded on December 4, 1956, at the Sun Records Studio in Memphis.

The Ampex 350, released at the end of 1953, was specifically designed for music studios. It could be operated using electric switch units for all control mechanisms, making it capable of remote control via wiring systems.

It offered speeds of 3¾ and 7½ inches per second (ips) or 7¾ and 15 ips, with frequency response extending up to 15 kHz at higher speeds. The full tape speed was reachable within 0.1 seconds of pressing the start button. Independent recording and playback electronics, along with separate record and playback heads, enabled simultaneous recording and monitoring. The 350 was available in single- or dual-channel configurations, as well as in portable or rack-mountable versions.

The stereo version was designated as the 351, with a special three-channel variant also existing within this type.