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From: eacj@theory.TN.CORNELL.EDU (Julian Vrieslander)
Newsgroups: rec.audio.high-end
Subject: Re: I want my VTA
Message-ID: <10050@uwm.edu>
Date: 8 Mar 91 13:37:00 GMT
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In article <10019@uwm.edu> eacj@theory.TN.CORNELL.EDU (Julian Vrieslander) writes:
>Some folks recommend starting by setting the tonearm, or top surface of
>the cartridge, to be parallel with the record.  I do that, but then I
>check the stylus rake angle to see if it's in the right ballpark.  This is
>the angle between the stylus and vertical, when viewed from the side.
>There may not be a visible line on the stylus, so you may need to just
...
>imagine a line through the center of the stylus chip.  This line should be
>close to vertical, or tipped forward a few degrees (5 to 10).  By "forward"
>I mean that the stylus tip should be behind the stylus top, or the tip
>should be closer to the tonearm pivot than the top.
...

After I posted this, I noted a possible source of confusion.  The stylus
rake angle that I described in the referenced note is *not* the same as
vertical tracking angle (VTA).  The latter is measured between horizontal
and a line drawn between the stylus contact point and the cantilever pivot
point.  VTA is also related to the orientation of the stylus in the cutting
head used in manufacturing the lacquer master disk.

You will often hear that optimum reproduction is obtained when the VTA of
the playback stylus matches the VTA of the cutting head used to make the 
record, and that the VTA's of modern LP's range from 15 to 20 degrees.
Several years ago, some folks at Shure did some testing in which they
varied cartridge orientation and measured distortion.  If I rememeber 
correctly, they found that both VTA and stylus rake angle had an effect
on distortion, and that it was not always possible to optimize both
simultaneously - because the stylus to cantilever angle is fixed.  The
Shure folks recommended a visual adjustment of the stylus rake angle, and it
was this recommendation that I relayed in my first post.  A summary of
their results appeared in Audio magazine several years ago.
-- 
Julian Vrieslander 
Neurobiology & Behavior, W250 Mudd Hall, Cornell University, Ithaca NY 14853    
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