2019-6-19 · The first commercial professional broadcast quality videotape machines capable of replacing kinescopes were the two-inch quadruplex videotape (Quad) machines introduced by Ampex on April 14, 1956 at the National Association of Broadcasters convention in Chicago.Quad employed a transverse (scanning the tape across its width) four-head system on a two-inch (5.08 cm) tape, and stationary …