Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site utcsrgv.UUCP
Path: utzoo!utcsrgv!spoo
From: spoo@utcsrgv.UUCP (Suk Lee)
Newsgroups: net.audio
Subject: Re: linear tracking query
Message-ID: <3255@utcsrgv.UUCP>
Date: Thu, 9-Feb-84 17:49:48 EST
Article-I.D.: utcsrgv.3255
Posted: Thu Feb  9 17:49:48 1984
Date-Received: Fri, 10-Feb-84 03:50:36 EST
References: <397@sii.UUCP>
Organization: CSRG, University of Toronto
Lines: 37

I would suspect that the variable pitch
"feature" was thrown away for two
reasons:  I don't think that many 
people actually use it, and it was a
"bug" turned into a "feature" that
turned back into a "bug" when quartz
locked oscillators became common in DD
turntables.  In the beginning...
direct drive turntables used an 
internal oscillator to lock the drive
speed (not necessary with the
synchronous motors typically used in
belt-drive turntables).  However, these
oscillators drift with temperature,
which prevented the manufacturers from
factory-setting the speed.  So, they
slapped a cheap strobe on the platter,
stuck in a pot in the oscillator 
circuit, and hey presto, we now have
a "feature".  With the advent of
quartz locked oscillators, it became
difficult to offer a quartz-locked
variable speed feature (most DD's with
quartz-lock turn it off when you turn
on the variable spead "feature"--
Technics being an exception), and I
suspect that manufacturers threw this
"feature" away since they don't need
it anymore.

-- 

From the pooped paws of:
Suk Lee
..!{decvax,linus,allegra,ihnp4}!utcsrgv!spoo