Finally, back into analog

  • Thread starter Thread starter Seeker of Rock
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Wil816 said:
This is my first post here.
Right. I was working in the repair department at TEAC/Tascam in Montebello, CA in the early 1980's when the 32 came out. I fixed about a thousand machines while I was there. Not a one of them needed demagnetization.
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Interesting.

What was your procedure then for determining the magnetic state of the tape path?

Or did the early 32's just fail too quickly to have had a chance to build up any stray magnetic fields? ;)

(kidding... sorta :p )
 
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Interesting.

What was your procedure then for determining the magnetic state of the tape path?

Or did the early 32's just fail too quickly to have had a chance to build up any stray magnetic fields?

(kidding... sorta )
Click to expand...
The 32's were just coming out at that time, and I may have only worked on a couple of that particular model. What I remember working on most were 3340, 3440, X7R, X10R, 5500 (boy those things were terrible with intermittencies!), the 4010 and related ones (I hated working on those!), 144 and 244 Portastudios (at least at that time, the heads wore out very fast!), 40-4, 80-8, and a lot of cassettes. I'm probably forgetting something major. That was 25 years ago.

Early in my tape-recorder enthusiasm, I used to use the demagnetizer religiously; but then I found that it was too weak to erase tape much at all even when the tape was laid directly against it, whereas of course the heads can erase and record on it. I reasoned, if the heads routinely during regular recording make their own magnetic fields that are even stronger than the demagnetizer's, what good is the demagnetizer? It left me wondering. And most of the other things the tape came in contact with were typically stainless steel or aluminum anyway, which are non-magnetic.

Then I read an article in one of the recording industry magazines about the myth of demagnetization. They took two identical tape recorders using identical tape, both in normal use, and ran them both 1,000 hours. One was "demagnetized" every few hours, while the other one never was. At the end of the thousand hours, they ran a full set of tests on both machines, and could not find any differences in performance. So I quit using the demagnetizer for good.

After that, I got the job at TEAC. Of course if a machine is in for one or more new heads, it had to be totally re-aligned anyway after changing the head(s); but if it was in for other problems like intermittent controls for example, then once those were taken care of and it was time to check the alignment before sending the unit back out, only minor adjustments to compensate for head wear were needed to bring the machine up to full performance. We used the alignment tapes regularly and were given replacements every few months; but I never noticed any difference between the old and new tapes, meaning the old had not been getting erased slowly either by running them on machines I had not used the demagnetizer on.
 
Reminds me of avalanche slopes

Take a screwdriver and touch it to a nice magnet. Now go and see if you can pick up screws with it. It can and we now have a magnetized screwdriver. I check my screwdrivers often and find that they pick up magnetism just in general use. Got a compass? Use that to test your tools.

So bring your magnetized screwdriver near your heads. They will also pickup some magnetism. Perhaps only a little. Take your compass and pass it near your heads. Did the needle deflect? Are your heads slightly magnetized? OH, by the way, Your compass is a magnet.

I take my (magnetized?) tools and demagnetize them on my bulk eraser before using them to align the heads. Takes longer with my head de-magnetizer but it will remove residual magnetism.

Who knows what the prior owner of Your deck did! I would demagnetize very well any deck new to me. I also tend to demagnetize before putting my MRL on a deck. It does not hurt to be cautious.

To say that you have not had a problem and thus will not have a problem is positive feedback. Positive feedback is unstable and a killer.

Reminds me of avalanche slopes. To say that I have crossed this avalanche slope 50 times before and never had a problem and so I will not have a problem this time is false. Without thinking the next crossing could kill you.

:eek:
 
The screwdriver's magnetism is nothing compared to the much more intense fields set up by the heads in normal recording. And if your compass is not attracted to a magnetic material like a tape head or a demagnetized screwdriver, it won't be able to find which direction is north either. To listen to some people, you'd think tape had to be kept away from motors (pneumatic tape recorders, anyone?) and even out of the earth's magnetic field-- which of course is impossible for practical usage.

You say "50 times." How many would it take to satisfy you? I repaired around a thousand TEACs from customers all over the hemisphere, and found that demagnetizing was never necessary for full performance. (But unlike your avalanche slope, I can't think of any situation where less that full performance from a tape recorder could cost someone their life.) While working at TEAC, I finished up an associate's degree in recording; and although we frequently cleaned the machines and practiced aligning them, the school did not promote demagnetization either IIRC.
 
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