the pinch roller built into the player would swing up into place to hold the tape against the drive capstan. 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 8-track cartridge tape speed was slower ( ips compared to Fidelipac's ips) and did not have adequate tape support pads, and thus was not "broadcast quality." The lower speed and narrower tracks in 8-track cartridges led to higher noise and reduced frequency response. The 8-track design also lacked a cue track. There were three sizes of Fidelipac carts available — the 4-inch-wide A size (Fidelipac Model 300, 350 and MasterCart), which was a standard 8-track size cart with maximum minute playing time at 7.5 ips (this was the most common and widely used size of Fidelipac cart); the 6-inch-wide B size (Fidelipac Model 600), a larger cartridge designed for holding longer programs; and the even larger 8-inch-wide C size (Fidelipac Model 1200), often used for background music applications like the Rowe Customusic. The A size Fidelipac cartridge was later adapted by Earl "Madman" Muntz in partnership with George Eash in 1963 for his Stereo-Pak cartridge system (also known as a 4-track cartridge), which differed in two ways — the number of tracks used (four in this case, with two played back at a time to provide a total of two programs of stereo audio), and the tape speed ( ips—the same speed as 8-track cartridges, as opposed to Fidelipac's standard ips). Unlike the Fidelipac players which used a stationary head, the Stereo-Pak system used a movable head to switch between the two programs (much like the 8-track format, which also used a movable head to select its four stereo programs). See also 4-track cartridge 8-track cartridge References External links History of Tape Recording Cart Equipment Archive Audiovisual introductions in 1959 Audio storage Tape recording Discontinued media formats Broadcast engineering History of radio American inventions 1959 in music 1959 in technology Products introduced in 1959