Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!husc6!m2c!wpi!reynhout
From: reynhout@wpi.wpi.edu (Andrew Reynhout)
Newsgroups: sci.electronics
Subject: speed control on a cassette deck
Summary: it's NOT that simple.
Keywords: cassette, speed
Message-ID: <3997@wpi.wpi.edu>
Date: 13 Sep 89 04:31:23 GMT
References: <4053@ct.sei.cmu.edu> <7683@microsoft.UUCP>
Reply-To: reynhout@wpi.wpi.edu (Andrew Reynhout)
Organization: Worcester Polytechnic Institute, Worcester, MA. USA
Lines: 30


   I can tell you from experience that altering tape speed on a cassette deck to any useful degree is *NOT* as simple as lining a pot through the supply for
the motor.  Sure, you can do that, BUT... if you do, the possibility exists
that it either won't work at all, or will work with adverse effects on the 
regularity of tape speed.  (faster then slower, producing interesting but
generally undesirable effects on the recorded material.)
   I was at a loss for years as to how to circumvent the adverse effects of 
slowing a tape deck.  I mean, I knew that Sony did it, but couldn't figure out
how to do it myself.

   Then, like an angel from heaven (OK, not really,) I happened across a cute
little schematic in one of the major monthlies (Either RE or PE..don't recall
exactly which one..) that detailed a circuit to solve this problem.  I never
tried it, so can't speak for its usefulness, but I suspect the reputation of
the periodical speaks well enough for that.  Basically, the circuit pulsed a
full supply of operating voltage to the motor, at a rate high enough that the
tape maintained a constant, but reduced, ips speed.

   So, I can either refer you to your library's most recent "Reader's Guide to
Periodical Literature", or tell you that I will get that information to you as
soon as I locate it (didn't bring my old copies of electronics mags to school
with me, and I'm looking at October or so before I go home.)

   On second thought, skip the "Reader's Guide...", it probably wouldn't have
a listing for Magnetic media recorders, motor speed control of.  Just look through that last three or four months of Radio Electronics and Popular Electronics
(and do it carefully...it wasn't an article, just a little 1/2 page thing, as I
recall...)

   If no luck, let me know...
   Andrew (reynhout@wpi.wpi.edu)