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New cartridge, now some adjustment questions.

I recently purchased a Shure v15mxr cartridge on closeout and mated it to my music hall mmf-2.1 table. There has certainly been an enormous improvement in sound quality. Just this week my back-ordered Hi-Fi News test record came in, and after running its tests, I can hear that my cartridge is not tracking all the test tracks perfectly. So I have a few questions.

1) It has some difficulty tracking the 300hz test tone tracks on side 2. On all three tracks there is at least slight distortion at some point in the track. I tried re-aligning my cartridge, but got no signifigant change. What factor is typically at fault here? Is it cartridge adjustment, or some other factor?

2) On the bias setting (anti-skate) tracks, it tracks the first two perfectly, but starts to break up slightly on 3, and terribly on 4. My table has limited anti-skate adjustment, (weight on a string). I made it better with some adjustment, but given that these are also 300hz test tones (as the tests above), I assume the two are related.

This seems to be a very helpful record, except they don't give many suggestions as to fixing the problems you find! Suggestions would be much appreciated!
jed
viridian's avatar
viridian
4,184 posts
 
That would be it, although the other question I asked, if the table was perfectly level, will come into play here. The more important question, as posed by others, is does this happen when playing real music, or just when playing test tones? Of course going down to one gram would cause you to diminish the anti-skate as well.
jed OP
10 posts
 
Ok, the problem is showing up in the music as well. After listening last night, I have a problem with a low frequency breakup in the left channel. It seems to be centered at one frequency, higher than a drum or bass, as those are sharp and defined, but somewhere in the low-midrange I'm getting distortion. I tried varying the anti-skate, but with no improvement.

What next?

Viridian--yes, the table is level- to the extent that my bubble level is within the innermost ring at any point on the platter. The platter itself seems to be the limiting factor now.
dougdeacon
3,338 posts
 
Try increasing VTF a bit, maybe up to 1.1 or 1.2g. Then fiddle with antiskate again.

Here are some other possibilities:

a) the suspension in this new cartridge is still too stiff to track certain passages,

b) you've discovered this particular cartridge's performance limits,

c) resonance in the platter or plinth at the problem frequency,

d) cartridge misalignment (seems unlikely from the symptom you described, but who knows?)
viridian's avatar
viridian
4,184 posts
 
Doug's right; it seems like a pickle. The Shure is very high compliance, so that can probably be eliminated. Is it possible to use headphones to see if it is an acoustic feedback issue? The bass frequency makes it suspect for that. You might also put a small mirror on the turntable mat, without a record and lower the cartridge onto it with the anti-skate completely off. This will magnify any problems with azimuth, perfect tangency to the record. Sometimes, if the stylus does not meet the record squarely, these problems can come up.
dougdeacon
3,338 posts
 
Marty,
Great suggestion to use headphones to test for acoustic feedback.

Jed,
If you don't have a way to listen via headphones with the speakers off, try playing the suspect passages with volume set fairly low. Listen to the L speaker with your ear very close to the speaker. If the distortion only occurs at higher room volumes then acoustic feedback is likely the culprit.
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