Teac MXT-111
Not a deck, not a tape - a calibration tool that only earns its keep if you already own the machines it was made to service.
Overview
The Teac MXT-111 trips up newcomers. It isn't a cassette deck, a receiver, or a music tape. It's a test tape - a factory-made reference cassette loaded with a 3,000 Hz tone at 0 dB. You play it back on a machine so a technician can verify tape speed and wow-and-flutter against a known standard. The fact sheet has nothing on the MXT-111, but Teac's own service documentation for its cassette decks names it repeatedly. That's where it lives: in the maintenance section, not the product catalog.
The MXT-111 was the high-speed companion to the MTT-111. Teac's service literature splits the work plainly - the MTT-111 covered low speed, the MXT-111 covered high speed. A technician reaching for the MXT-111 was working on a deck whose transport ran at the faster rate. The tape carried the 3,000 Hz signal at 0 dB that the deck's output was supposed to reproduce.
The service procedures were built tightly around the MXT-111. Teac didn't treat it as one option among many. For the speed check, you play the MXT-111, read the output on a frequency counter, and adjust a trim pot until the counter settles at 3,000 Hz. The spec was tight: ±30 Hz at the middle of the tape, ±45 Hz at the beginning and end, with fluctuation held under 30 Hz. For wow and flutter, you run the MXT-111 through a wow-and-flutter meter and confirm the reading comes in at 0.08% WRMS or less, weighted. The caution note in the manual shows how seriously Teac took measurement conditions. Readings had to be taken at the beginning, middle, and end of the tape, with specific tape-pack positions on the cassette half-scale to keep the takeup and supply tension consistent.
The pinch control range shows how much adjustment latitude the transport was expected to have. At the extremes of the pitch control, minimum speed sat below 2,610 Hz and maximum speed above 3,390 Hz, with the center position as the reference point. That's the window a technician worked within when aligning a deck against the MXT-111. It's also why the tape had to be accurate. If the reference drifted, every deck calibrated against it drifted too.
One detail in the service documentation shows how Teac positioned the MXT-111. The specification notes in the manual carry a line stating that specifications were determined using TEAC Test Tape MXT-111. So the tape was the measurement standard the published numbers were derived from. Teac didn't sell it as an accessory alongside the decks; the factory used it to define what the decks were supposed to do.
For anyone who owns a Teac cassette deck from the period the MXT-111 was current, the tape is an odd item. You don't listen to it. You don't show it off on a shelf next to a silver-faced receiver. It's a consumable reference - a cassette meant to be played, measured against, and eventually worn out or replaced. That's why surviving examples are uncommon, and why collectors who service their own decks tend to treat a genuine MXT-111 as a working tool rather than a display piece. The fact sheet doesn't document production years, original price, or market values for the MXT-111, and those details aren't readily available in the sources at hand.
What the documentation does establish is the tape's technical role. A 3,000 Hz signal at 0 dB, a speed tolerance measured in tens of hertz, a wow-and-flutter ceiling of 0.08% WRMS - these aren't consumer-facing numbers. They're the numbers a bench technician needs to bring a transport back into spec, and the MXT-111 was the tool that gave them meaning. Without a proper reference tape, you're guessing. With one, you're measuring.
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