TT set up question


I was listening to a friends TT yesterday and it sounded really good, but on two LPs there was a crackling sound near the end of the LP. This sound did not occur earlier in the LP, and both of the LPs were new. What did he do wrong?
uppermidfi
This si known as "inner groove distortion" and is an indication of a cartridge alignment problem. Some cartridges are more susceptable than others. Carefully check alignment and anti-skate settings.
Sounds like end of side distortion to me. Did it sound like a coarse fuzziness during load passages, or more like the tics and pops of dust on the LP ?

Hello. have him recalibrate as noted by Kentamcolin. However, I have also experienced surface noise when playing new records even after calibration. Some new pressings are susceptible to noise due to the cutting process and residue/contaminents which is left behind in the grooves. Have him thouroughly clean the playing surface which is recommended with all records, new or used.

Happy :D Happy :D Tunes!!
Inner groove distortion can be caused by misalignment of the cartridge or incorrect anti-skating. The alignment and overhang settings should be checked with an appropriate guage that is usually supplied with the tonearm. If you notice that the distortion is mostly in one channel, then it's usually the anti-skate setting. Distortion in the left channel (the inner groove wall) requires a decrease in anti-skate force, while distortion in the right channel requires an increase in the setting. The proper anti-skate setting should allow the cartridge to ride more centered in the groove, with equal force and tracking ability for both channels. Good luck, and let us know what you find.
I haven't had a table for a while, but how do I know if his antiskating is set right? Which way should the arm deflect when it's raised from the LP?
I have used the Wally Skater in the past to set my anti-skate on my Kuzma Stogi tonearm. I found it interesting that the factory recommended setting based on my cartridge VTF and the Wally results were different, by quite a bit. I confirmed the Wally anti-skate results with a test record.

Nsgarch has posted an interesting method for testing anti-skate. It is is the opposite of what you mentioned. Instead of deflection of the tonearm on the rise, look at what happens to the stylus when you lower it onto a spinning record. If you don't have the anti-skate set correctly you will notice a deflection one way of the other. Good light and perhaps a magnifying glass help with this test.
I haven't had a table for a while, but how do I know if his antiskating is set right? Which way should the arm deflect when it's raised from the LP?
Observing which direction an arm deflects during cueing does not tell you how to adjust antiskating. That idea is absurd.

One problem at a time. You haven't answered Seandtaylor99's question, which was important and well chosen. Identifying your friend's problem depends on the answer.
It wasn't end of the side distortion, if it were, I would have responded to the question. There was probably a couple of minutes left on each LP every time it happened. The sound was similar to an electrical discharge.

Doug, sorry for being too stupid to know that my idea was absurd! If only I knew as much as you...

Clio, that's some good advice, I will check it next time I'm there, or just pass the info along.
That's the last time I ever answer one of your threads. If you knew it was not end of side distortion why didn't you specify so in the original thread. You could be a little more gracious with people who have voluntarily tried to help you out.
Uppermidfi,

Please relax. I didn't say you were stupid. I said that a theory you postulated was "absurd", ie, "unrelated to reality". That was a statement of logic concerning a hypothesis, not an insult. I could come up with much better insults than that, honest!

Why didn't I explain antiskating in a nice, friendly way? For very good reasons. It was kind of Clio09 to offer all that excellent information, but antiskating has little or nothing to do with your friend's problem. That problem is important and needs to be addressed without distraction.

Since you've twice refused to answer Seandtaylor99's very pertinent question and are uncomfortable with learning I doubt I can help very much. I will offer this: tell your friend to STOP playing valuable records on that rig. Those noises like "static discharge" indicate a high probability of permanent vinyl damage from every play.

This can be fixed, usually quite easily, but not by adjusting antiskating.

Good luck,
Doug
I did answer Seans question! I wasn't ignoring him becuase I did not appreciate his response. I did not think it was the issue, so I didn't respond. I had no idea people were so thin skinned. I had never heard of end of side distortion before he mentioned it, but as I pointed out it was not at the end of the side, IT WAS SEVERAL MINUTES BEFORE THE SIDE ENDED!

I am trying to help a friend, I cannot explain this anymore clearly than I already have! I don't know what's missing from my explaination.
The gist of Sean's question was whether this noise tended to occur during loud passages. (He actually wrote "load passages", which probably didn't help you interpret the question.) At any rate, you haven't answered this yet.

So, was this "static discharge" noise coincident with dynamic peaks in the music? Or did it also occur at random moments during quiet passages?

Think carefully about the answer, the diagnosis depends on it.
"IT WAS SEVERAL MINUTES BEFORE THE SIDE ENDED"

End of side distortion can occur anywhere in the last couple of tracks on a side. It can start several minutes before the side ends. It is typically coincident with the louder passages of music and sounds similar to an over-saturated cassette recording. It varies from LP to LP and can be almost impossible to eradicate on some LPs.

Minimization involves very careful cartridge alignment using a protractor, a bright light and a steady hand.

Depending on the deck, the cartridge and the LP you might have to live with some distortion (or replace one or all of the above).

I don't know why I bothered really, but there you are ... take it or leave it.
At the point when it occurred I never thought to recall what was happening in the music. I don't know if the passage was loud, or otherwise.

The reason the distortion stood out was because it wasn't anything we had heard on those LPs before. He didn't know what was wrong, and I had never heard of this kind of problem before.

Sean, thank you for trying to help. It isn't that I don't appreciate your help, I simply didn't understand what was taking place, or how to explain it, and then how it related to the question you asked. Maybe I read through your response too fast and missed the gist of it.

It seems as if the discharge was random as opposed to being associated with loud passages, but again, I'm not positive.
Since you're unsure, here are the main possibilities. There are three common causes of "static-like" noises:
_____
1. Pressing flaws from the factory.

These can occur anywhere on a record, though they tend to occur on the L channel more than the R. There is no cure except to replace the record.

Since you've heard these LP's play without such noises this can probably be ruled out.

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2. Stylus mistracking due to inadequate downforce, record dirt and/or stylus dirt.

This tends to occur in timing with dynamic peaks in the music. That is when a stylus is most likely to mistrack. It is also more likely to occur as the stylus get nearer the center of a record.
This can be cured by addressing the causes. Records must be cleaned before the first play. Styli must be cleaned after every side. Then try increasing VTF until the noise goes away.

IMPORTANT: stylus mistracking must be cured immediately to avoid scenario #3.

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3. Permanent damage to the record from being played under the conditions described in #2.

Since this damage is caused by problem #2, it occurs at the same times.

It is nearly impossible to hear the difference between #2 (active mistracking) and #3 (damage from previous mistrackings). The only way to know is to try the cures for #2. If these don't help then one suspects #3.

There is no cure except replacing the record.

You've got some detective work ahead of you. Good luck!
Doug
I'm not sure when I will be able to get back to his place to listen again, but I will be listening differently when it happens. He has the zero dust stuff and a record cleaner, but that doesn't rule out the possibliity of dirty LPs.

Is there a point when tracking weight is simply too much? I know he has a digital scale, but that doesn't rule out errors. I'm just trying to get some ideas here, I don't have answers.
Is there a point when tracking weight is simply too much?
Yes. Every cartridge has a range of VTF where it tracks and sounds best. Too light and you get the problem described above. Too heavy and high frequencies usually get smothered. Heavier still, above the design range of the cartridge, and you risk accelerated wear of the suspension, stylus and vinyl.

For an excellent primer on how to set VTF (and VTA) by ear, give your friend this link:

http://www.walkeraudio.com/fine_tuning_your_turntable.htm

I know he has a digital scale, but that doesn't rule out errors.
Very true. A scale can't help you find the optimal VTF for a cartridge. That must be done either by listening to music or with test records. All a scale can do is:

a) get you in the ballpark and,

b) identify the optimal VTF after you've found it by listening.

Knowing the exact VTF a particular cartridge likes makes swapping cartridges and other adjustments go faster. Otherwise a scale serves little practical purpose.

Doug