From: utzoo!decvax!harpo!seismo!rocheste!stevans
Newsgroups: net.audio
Title: Pinch rollers and biasing
Article-I.D.: rocheste.364
Posted: Wed Jan  5 04:32:52 1983
Received: Thu Jan  6 02:41:24 1983

I have been told not to use alcohol on the pinch-roller, because it
removes moisture from the roller, causing cracking of the surface.
Stereo Review and a few other publications disagree, but I can see
the point.

Someone has recommended lacquer thinner as a substitute, but this will
dissolves plastic very easily.  The housing of the pinch-roller on my
unit is plastic, so I am reluctant to switch unless somebody has a
non-plastic-dissolving alternative (besides water, which might not be
too bad).  Perhaps a judicious mixture of alcohol and water, say %50?

Someone else has explained biasing here on net.audio.  The recorder's
heads will not become magnetized, since the bias is an AC signal averaging
about zero.  Since the average magnetic field at the head in both recording
and playing is zero, how would a demagnetized head ever become magnetized?
And if it gets magnetized, normal use will tend to unmagnetize it again.

Am I wrong again?

                             Mark Stevans, U of Rochester, NY
                             (allegra or seismo or brl-bmd)!rochester!stevans