Fidelipac

The Fidelipac, commonly known as a "NAB cartridge" or simply "cart", is a magnetic tape sound recording format, used for radio broadcasting for playback of material over the air such as radio commercials, jingles, station identifications, and music, and for indoor background music.

It was developed in 1954[1][2] by inventor George Eash[3][4] (although the invention of the Fidelipac cartridge has also been credited to Vern Nolte of the Automatic Tape Company[5][6]), and commercially introduced in 1959 by Collins Radio Co. at the 1959 NAB Convention.

The cartridge was often used at radio stations until the late 1990s, when such formats as MiniDisc and computerized broadcast automation predominated.

While later machines from ATC, ITC, Harris, and others had the pinch roller automatically engage the cartridge when the play button was pressed (the capstan motor was already running when the cart was inserted), early machines such as Sparta, Spot-matic, and others required the operator to also push or pull a separate lever to move the pinch roller into place before playback could begin.

The lower speed and narrower tracks in 8-track cartridges led to higher noise and reduced frequency response.