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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!mtuxo!drutx!druxu!mohler
From: mohler@druxu.UUCP (MohlerDS)
Newsgroups: net.audio
Subject: Re: Turntable-platter resonances
Message-ID: <1549@druxu.UUCP>
Date: Wed, 12-Jun-85 17:00:00 EDT
Article-I.D.: druxu.1549
Posted: Wed Jun 12 17:00:00 1985
Date-Received: Thu, 13-Jun-85 02:15:44 EDT
References: <682@charm.UUCP>
Organization: AT&T Information Systems Laboratories, Denver
Lines: 26

I have found that the air trapped below the disc and the disc damping
are not the problem, but rather the cause of two other problems. A
moving coil cartridge can have problems if high frequencies (20K & up)
get in the generator circuit. This can have the effect of causing
intermodulation distortion and high frequency mistracking which are
definitely audible! I suspect that the audiophiles that use special
mats and clamps are reducing intermod. and low level high frequency
tracking problems rather than damping "vinyl ringing" and removing
air space vibrations. Moving magnet cartridges tend to be less sensitive
to this but it can still be a significant problem. I have experimented
with mats and clamps and I believe my results support my opinions
listed above. 

Another comment to those that have been reading the
postings on clamps. Beware of the EON POD! Depending on the shape of the
tonearm and the length of the lead-out grove the arm can hit the
POD!!! When I worked at an audio store during college I saw 3 very
expensive cartridges "meet their maker" due to the POD.

			David S. Mohler
			AT&T - ISL @ Denver
			drune!mohler <---- Notice new path.

"At the approach of daybreak...the tweeks disappear. They
probably returned to a certain castle in Transylvania."  - AT&T -
BELL LABS RECORD 1984 !!