Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff. The name AMPEX is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excellence. At one time public, Ampex is currently a privately held company.

Alexander Matthew Poniatoff established the company in San Carlos, California, in 1944 as the Ampex Electric and Manufacturing Company. The name came from his initials plus "ex" to avoid using the name AMP already in use. During World War II, Ampex was a small manufacturer of high quality electric motors and generators for radars that used Alnico 5 magnets from General Electric. Ampex's first offices were at 1313 Laurel St. San Carlos California, "Howard Ave. at Laurel".

Near the end of the war, while serving in the U.S. Army Signal Corps, Major Jack Mullin was assigned to investigate German radio and electronics experiments. He discovered the Magnetophons with AC biasing on a trip to Radio Frankfurt which gave much better fidelity than shellac records. Mullin acquired two Magnetophon recorders along with 50 reels of BASF Type L tape and brought them to America where he produced modified versions. He demonstrated them on May 16, 1946, to the Institute of Radio Engineers in San Francisco.