At what VTF are you running the cartridge?
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Jed, the Hi-Fi News test disc is very challenging and, basically, it is intended to show the breaking point in just about every setup somewhere in those grooves. My recommendation to you is to set aside the test record and play a good quality classical orchestral recording. Listen carefully, and make some final VTA and VTF adjustments by ear. If the orchestral music is being played cleanly, you're in good shape irrespective of what you hear on the test record. For setting up by ear, follow Lloyd Walker's turntable set up recommendations.
You say that you are tracking at 1.5 grams, that would indicate that the brush is down. Have you tried putting the brush up and tracking at 1gm? Sometimes, the brushes don't work right. Have you checked the plinth of your turntable to be sure that it is level? A static balance arm depends on the table being level to work properly. When you hear the breakup, which channel breaks up first, left or right?
The instructions that came with the sure indicated that VTF be set at 1.5 grams, and if the brush was down, actual tracking weight would be 1 gram. I have not been using the brush, as even before I had the test record I could hear the effect it had on the music and the noise floor. With the brush down on the test record, the cartridge does not track well at all. So you are saying I should try 1 gram, without the brush?
Jed, please read the directions that came with the Shure again. They indicate that you must track at one gram with the brush up, and one and a half grams with the brush down. This is because the action of the brush pushes the arm upward. The actual effective tracking force is the same either way. You are tracking way too heavy. Try again, you are way off. Remember, this will cause you to reset the VTA and anti-skate as well. You did not answer my other question. Which channel breaks up first?
Viridian is correct about the brush and its effect on VTF. You've got it backwards.
I agree with Rushton on the HFNRR test record. It's an interesting toy with little practical utility for dialing in a cartridge. Check out the link he posted for a much more reliable (and educational) method for adjusting VTF and VTA.
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?It's likely that nothing's at fault. My best arm and cartridge ($4K and $7K list respectively) behave exactly the same way. If the "buzzing" is about equal on all three tracks that's some indication that antiskating is set pretty well. Other than that, those tracks are of no practical use.
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.Those tracks are nearly useless, and if misunderstood (as you're currently doing) they can be a positive menace, because you will set antiskate too high.
It is incorrect to think of those four tracks as some sort of test, which a better rig or better adjustments will "pass" by playing the later tracks "better". My best sounding cartridge "tests" far worse than my worst sounding cartridge on those four tracks.
One of the problems with those tracks is that they're all near the inner grooves. Unfortunately, the skating force we're trying to compensate for varies across the record. Adjusting antiskate for one particular groove that's near the end (or beginning) of a side will necessarily result in a setting that is progressively less accurate the farther the arm moves from that track.
This is why the three tracking test bands on side 2 are better for a first approximation antiskate setting. They're evenly spaced across the record so you can choose a reasonable compromise for antiskate, which is always a compromise. As your ears get more finally tuned, you'll be able to adjust antiskate by listening to music. Then you can file the HFNRR record away among your other idle curiosities! ;-)
Ok, I have set the VTF to 1 gram, without using the brush. I have run some of the test tracks again, and the break-up is more on the left channel, although fairly constant on both. (For the 300hz test tones on side 2). I will spend some time listening tonight, and report back. Thanks for the help so far.
If breakup is more on the L channel on all three side 2 tracks then you probably need to reduce antiskate a bit.
If the cartridge is brand new, don't go too crazy. Just get it close and listen to music for 50-100 hours. Check it again after the suspension has a chance to break in.
Cheers, don't forget to enjoy the music!
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.
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.
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.
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?)
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.
Great suggestion to use headphones to test for acoustic feedback.
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.
Thanks for all the responses. It's definitely not acoustic feedback - I should have mentioned that all of my listening is through headphones. I increased tracking force 1/10 gram at a time last night, and listened to music. At 1.5 grams, the breakup is gone. At that tracking force it also tracks the test tracks nearly perfectly, especially as I spent some more time adjusting anti-skate. So, is there any problem running at 1.5 grams? (although I'm not sure I want to know, as it definitely sounds best at that weight!)
Viridian- I'm using the turntable basics mirrored alignment gauge, and aligning the cartridge body square to the grid lines. To the best of my current ability, the stylus also looks square, but it's pretty hard to see. Is this what you meant?
You need to also consider that the Shure scale is quite inaccurate and insensitive. I've compared my Shure scale readings to a calibrated digital scale and found mine to be off by .4 grams (read 1.1 when actual weight was 1.5) and another scale was off by .3 grams in the other direction.
Go with sonic results of experimentation, just don't go to extremely high downforce.