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From: @sun.acs.udel.edu:hamilton@sun.acs.udel.edu (hamilton)
Newsgroups: rec.audio.high-end
Subject: Trimming MSB on DAC
Message-ID: <2589@uwm.edu>
Date: 26 Feb 90 15:13:55 GMT
Sender: news@uwm.edu
Lines: 16
Approved: tjk@csd4.csd.uwm.edu


I read in the current issue of CD Review that it is possible to adjust the 
trim pots on the D-A convertors of a CD player to improve linearity.  They
adjusted the MSB on the converters of the Vector Research VCD-410R so that
the linearity error was "essentially 0 error to well below -100dB."
This happens to be the CD player I own, and I opened up my player, and sure
enough, next to each D-A chip was a small trim pot.  Obviously there is 
great potential here to improve sound quality for _FREE_.  I imagine that
it would work with any CD player with trim pots.  Linearity below -100dB is
something found only in the most costly CD players, and maybe in the new
1-bit machines.  Does anyone know what is needed to perform the adjustment?
Can it be done by the average joe?

J. P. Grenert
hamilton@sun.acs.udel.edu