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A '''loop bin duplicator''' is a specialized [[audio tape]] machine used in the duplication of pre-recorded [[compact audio cassette|audio cassettes]] and [[8-track tape|8-track cartridges]].
Digital loop bin duplicators were first introduced in the early 1990s. They had fewer moving parts than previous systems, so were more reliable to operate.
== Analog loop bin duplicator ==
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An analog loop bin uses a long loop of either 1/2" wide (for cassette duplication) or 1" wide (for 8-track tape duplication) loaded in a large bin located in the front of the duplicator. This loop master tape is loaded into the duplicator's bin from a traditional open-reel of tape, where the program material has been recorded to it using a studio-type multitrack tape recorder in real-time beforehand. The loop tape for cassette duplication has 4 tracks on the loop bin master tape (2 stereo tracks for Side A recorded in one direction, and the other 2 for Side B recorded in the opposite direction), and for 8-tracks has all of the 8 tracks (4 2-track stereo programs) recorded in one direction. The loop-bin master tape is read by the duplicator at a very high speed. For cassettes, either 32, 64, 80, or 100 times the normal speed of playback (1.875 [[inches per second|ips]]) of an audio cassette (60, 120, 150, and 187.5 ips respectively) is used, and 10 or 20 times the normal speed of playback (3.75 ips) is used for 8-track duplication (37.50 and 75 ips respectively).
While this loop is being played back, the audio signals for the A and B side (or all 4 programs for 8-track) are sent to a "slave" recorder or an audio bus that contains multiple "slaves". The "slave" records from the loop bin master tape the 4 tracks for both A and B sides to
The loop of tape in the duplicator's bin usually will have a segment of clear leader spliced in between the beginning and end of the tape loop (with some duplicators using a metal foil splice instead). This clear leader splice is read by an optical sensor (or in the case of a foil splice, coming in contact with electrical contacts in the tape path) in the loop bin duplicator, which triggers a cue tone that is recorded to the reel of pancake tape. This cue tone is read by the loader, and engages it, for cassettes, to stop and cut the tape from the pancake and either splice it to the leader in the C-0 cassette shell, or for 8-tracks, to disengage winding to an internal cartridge reel on the "sidewinder" mechanism and then cut the tape (a process for both types of media called "de-spooling"), with the winding resuming to a new reel afterwards. In fact, part of this de-spooling tone (also known as a "tailor tone" or "trigger tone") can be heard at the leader splice or foil splice of some previously recorded audio cassettes and 8-tracks respectively, as a very low-frequency [[arpeggio|arpeggiated]] rumbling of about 20 Hertz, sounding similar to how [[Motorboating (electronics)|"motorboating"]] sounds with a radio or audio amplifier affected by such, but as an actual higher-frequency tone when played back at a higher speed (as it was when recorded to the tape at high speed during duplication).
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==External links==
* [http://www.audiodups.com/manufacturing.html Bin Loop Tape Duplication (With pictures)]
* [https://web.archive.org/web/20030318000601/http://www.opticaldisc-systems.com/2002MarApr/Equipment64.htm Digital Bin Loop Master Machine]
* {{usurped|1=[https://web.archive.org/web/20101208122537/http://www.8trackheaven.com/ampex.html "My year at Ampex", by Ron Schauer, a former employee at Ampex's tape duplication plant]}}
==References==
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