Unfortunately I could not find any manual for free (one on ebay for $80). The units tends to sell for between $100 and $200 and because of the weight they are often listed "for pick up only". Otherwise the shipping would cost way more than the unit itself (that beast looks like if weighs a hundred pounds).
Could it be used for audio? I think so. There is even a Microphone input on it. Without a manual it is hard to tell much.
It looks like it is designed to do 4 channels in a calibrated fashion so that the input voltages being recorded are the same as the output voltages being produced.
From
http://www.alliancetesteq.com/equipment ... t-hp-3964aQuote:
The Agilent 3964A Tape Recorder is a four channel recorder; 1/4 inch tape; Speeds: 15, 7 1/2, 3 3/4, 1 7/8, 15/16, 15/32 IPS.
It is selectable FM or direct electronics, remote control (TTL), and for switch selection of tach or tape servo.
One seller said he had checked his out and it was completely working, but that he had not used a tape!!! How do you really check out a recorder without tape??? I suppose that is like the people who "restore" radios by wiping off the dust.
At this site I found the following
http://hpmemoryproject.org/wb_pages/wall_b_page_14c.htmQuote:
The HP 3964A,
Instrumentation Tape Recorder
As late as the end of the 1970s, internal computer memories were far too small to be able to serve as measurement data storage, especially those data streams generated by wideband signals. Auxiliary storage was the answer.
Consequently, even in 1977, the Instrumentation Tape Recorder like the HP 3964A, shown on the left, was introduced as a new product in the general catalog. One key feature was its desirable portability, and yet impressive data performance.
The Model 3964A, 4-channel, utilizing a 1/4-inch (6.3 mm) tape width format, was designed to meet the demand of the individual and OEM users.
The 3964A has one four-track record head, and one four-track reproduce head using in-line track configuration. Possible tape speeds are the following: 1.19, 2.38, 4.75, 9.52, 19.05, and 38.10 cm/s. The 3964A passband is 70 to 64,000 Hz, at maximum tape speed.
Oh, you transposed numbers in the title of your posting.
Best of luck,
Curtis Eickerman