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From: urban@frith.egr.msu.edu (Mark Urban-Lurain)
Newsgroups: rec.audio.high-end
Subject: Re: Tape Squeals
Message-ID: <7037@uwm.edu>
Date: 17 Oct 90 13:03:42 GMT
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Approved: tjk@csd4.csd.uwm.edu

In article <6869@uwm.edu> JFARRINGTON@EAGLE.WESLEYAN.EDU (Jim Farrington) writes:
>In reply to Steve Graham's squealing reels, I think I can throw some light
>on the subject (though you may not like the answer).  Until the '70s one
>of the main components to audio tape was whale oil as it was and is the best
>agent for keeping tape supple.  When whaling began to be frowned upon, companies
>began to look for new agents to replace the whale oil.  As we are hearing
>now, the stuff they began using in the '70s is now disappearing from the
>tape which is becoming brittle and "sticky".  The high-pitched squeal you hear 
>is actually the tape catching and releasing on the heads many thousands of 
>times per second.  Ampex tapes from this time are notoriously bad in this
>respect.

One article (sorry ,don't have the reference handy) I recently read
said that the problem was not that these lubricants evaporate, but that
they actually undergo chemical changes which cause them to become
"sticky".  The solution they proposed was to fastwind the tape a couple
of times, then bake it in a low (~200 degree f) oven to dry out the
lubricant.  They then suggest playing only for dubbing purposes, as the
tape will have no lubricant, but at least would not have an "adhesive".

I've not tried it as it seems a little radical; I think I'd try the
cloth method Jim proposes first.



--
Mark Urban-Lurain                        urban@cpswh.cps.msu.edu
Computer Science Dept.                   urbanluraimg@clvax1.cl.msu.edu
Michigan State University                (517) 353-0682   
A-714 Wells Hall, East Lansing, MI  48824