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Re: [ARSCLIST] cassette crackle

At 05:54 PM 2008-09-18, Michael Biel wrote:
Most of what I will say here concerns open-reel tape because cassettes are so damn small and some of these problems concern mainly older and wider tapes. But I'll get to cassettes in the end.

...My first machine 48 years ago was an ill-fated Wollensak T-1616

That is an odd coincidence, so was mine! Did it really come out in 1960? I must have gotten it towards the end of the run, as I think I got mine in 1962 or 1963. I know I had it in 1963 as I recorded a bunch of Kennedy funeral off-air stuff which I still have.

The selector allowed you to move the stereo heads down slightly to center on half-track stereo tapes and miss playing part of the guard band with the lower track.

I had John French mount a 4-channel 8-track 1/4-inch head on an elevator assembly, so I can grab an 21-mil track across the entire width of the 250-mil tape.

The other benefit concerned old warped tapes, especially full-track, and this is where the controversy comes in. On many old tapes, especially acetate, what had been a razor-edge straight recording from the original full track head has now become a curvy-wiggle shaped line. If you play this tape back on a real full track head the high frequencies will drift in and out because they will not be totally in azimuith allignment and some frequencies will be nulled out when a positive and negative portion of the same wave hits the head at the same time. I found that if I used the Wollensak instead of a full track machine, I could move the head track selector up and down to find a place where there was no tape warpage and none of waves would be nulled. And as for those who will yell HEAD BUMP, I say that sometimes the increased bass sounds good on the old tapes, and it can be EQed out if you insist.

The head bump is the least of the problems. I have other heads with an 82-mil track close to the centre and a central 43-mil track which have both come in handy for this type of thing.

On the other hand, the Studer A80 with the stabilizing roller right before the play head does wonders in playing some of these tapes full track so you retain the full dynamic range and relative freedom from dropouts that full-track offers.

I have seen some people suggest using a four channel quad head to play back full track tapes and select one AND ONLY ONE of the tracks to use.

I've done that on some really bad tapes trying to capture what I could, although signal-to-noise and dropout performance suffers. Nothing beats track width (to a point and that point is limited by azimuth stability).

What is interesting is I used to have a fair amount of problems playing full-track 7.5 in/s acetate tapes on Studer A810s. I'm just not seeing these problems with the A80.

When I was in Moscow in 1995, Alexander Tikhonov took me to a studio that did the restoration work for Radio Moscow. He had a special russian-made machine (I don't think it was the Hungarian machines that were almost exclusively used in the Radio Moscow studios, but I would have to check my videotape) that was designed for restoration playing. I don't think it was a modified or one-off machine. No recording electronics or heads, of course. (95% of us have no need to record tape anyway.) It had maybe a dozen different interchangable head blocks for all sorts of different formats with all sorts of different dials on them for adjustments. Never seen a machine more versatile. Studer make one like this??

Studer used to make external azimuth adjustments and I have two head assemblies for the A80 that have these and one for the A810. Both Studer and Sony on the APR-5000 use good-quality metric hex-head screws for azimuth on normal blocks and I've yet to strip one, but some of the really old A80 blocks which have come my way in pieces were stripped on the azimuth screw "nuts" in the block.

Nobody has ever made an open reel player for .150 tape, have they?

Yes, at least Studer made the A80QC which had dual capstan motors, but it may have other challenges. I passed up several for $100 and am now kicking myself. However, my friend Don Ososke has suggested using BASF SM shells and also TDK MAR shells to better control problem tapes. I've yet to try that, but I did obtain some of the shells.

Maybe some of you who have worked more with cassettes than I have (I HATE them) can recommend machines that have more sturdy and accessable adjustments than the usual crap, and some that retract the pressure pad.

While I don't like cassettes, they go a long way towards paying the bills. I currently have six Nakamichi Dragons. These automatically adjust the azimuth if there is >3.5 kHz material on the right channel. Many Nakamichi machines push the pressure pad out of the way and stabilize the tape and provide tension through dual capstans.

On paper, I have a mod for the Dragon that should permit azimuth lock, manual azimuth adjustment, and digital azimuth readout. I've yet to build the first one to test the concept.

The Nakamichi CR7 is also a good choice for transferring cassettes.



Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.

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