Poor man's 688 tape head alignment test?

Discussion in 'TASCAM Analog Forum' started by AmpAnalog, Dec 30, 2018.

  1. AmpAnalog

    AmpAnalog New Member

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    Just throwing it out there:

    I don't have proper equipment to align the 688 tape heads or check the tape travel (this includes the Teac MXT-111 tape with the 3kHz tone and MXT-1161 tape with 315Hz and 6.3kHz for azimuth and head touch). There's also head adjustment jigs (part #s: 5736006600 and 5736006700) which i can't seem to source on the used market.

    That said, and trying to get as close as possible, will recording a test tone on cassette side A on all 8 tracks (bussed from a single, known-to-be-good channel) and then FLIPPING the cassette to side B for playback tell me how closely aligned the tape path and heads are aligned from track to track? I would think without "bleed" from track to track or loss of dB per track I'd be pretty close to decent alignment.

    Seems as if a recorded tone on track 1 (side A) played back correctly (with the same metered level as when originally recorded) on the B side (which will effectively be track 8 now that it's flipped) would indicate a reasonable alignment within the 688. Testing the signal from a frequency generator as it's recorded (monitored post tape) and played back through an oscilloscope should tell me provide useful info.
    Until I can find the rest of the test equipment, I can't think of another way to try out the repro function.

    Thanks, as always for any insight you may have.
  2. wkrbee

    wkrbee Active Member

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    Unless you have been playing with the head adjustment screws,most likely the heads do not need to be adjusted. You need the playback alignment tapes to set up the heads. The errors will be compounded trying to use the record method you describe. There is not monitor tape mode on the 688. The MXT-111 was for tape speed cal.The "Tape adjustment jigs were pretty much only used when the head is replaced. Skywave.tdr may have some input.
  3. AmpAnalog

    AmpAnalog New Member

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    Thank you wkrbee. I understand what you mean regarding compounding errors. Good to know, too, that the jigs were just for aligning replacements.
    I was under the impression that the Cue Monitor was post-tape. I'll have to run more tests to make sure I comprehend what I see (on meter bridge) and hear on output. Appreciate the insight.

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