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
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:
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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