Lots of great information, thanks notebook and L.
I think L misunderstood, the developing is not to digitize the contents. But to verify if there is anything on it at all, how strong the tracks are, and what kind of signals we can expect from each track.
Unless we are able to find a 7-track instrumentional recorder, I plan on using a 1/2 inch Otari 5050 8-track studio recorder. So far the speeds I have seen on documentation are selectable on the Otari unit, 7.5 and 15 IPS.
8 =/= 7 tracks of course, so I hope to accomplish this in two ways:
1. Move the 8-treack head to align one of the 8-tracks with one track on the 7-track tape. Repeat process for all 7 tracks until everything has been digitized.
Question: Are this many replays damaging to the tape, is head gap and track height indifferent enough to give adequate signal?
2. Get a 7-track head, from a broken instrumentation recorder, or a 7-track computer tape drive (Big mainframe reels) and make a head carriage assembly so it can be put in place of the 8-track reproduction head. Connect the 7 tracks to the normal playback amplifiers of the Otari, align 7-track head, and digitize all 7-tracks at once.
Questions: Is output from 7-track computer tape drive and instrumentation head close enough to the 8-track audio head so it can be connected to the Otari playback amplifiers without damage?
Is wiring compatible, was it always basically the same?
Where to get 7-track calibration/alignment tape?
If either one of these has been completed, we will be left with 7 WAV or FLAC audio files for each tape, digitized at 24bit/192Khz. These files contain the raw signals received from the playback machine.
I do not think recording an FM signal like this is problematic? it is just a wave form like any other audio signal right?
I do not think 'direct' recordings should be a problem, as no demodulation is required.
With today's computational power it should be possible to then take the FM wav file and demodulate it with a computer program. As long as we can find the modulation settings used.
Sorry for so many questions, and I am thinking far ahead here. This is so exciting.
Baby steps.
Niels