Compressor crackling

[TwototheValley]

It seems that the more it squishes the signal, the more crackling is audible. My guess is that it may be the compression pot. I can't be sure, but I think it gets worse depending on the position of the knob.
Thats the best I can describe it. I tried cleaning it but no help, although it dosn't have the same kind of sound that a dirty pot makes.

So far I've replaced the power supply, power jack, trimpot, stomp switch and the LED.

Hmm...

Quoting this old thread from 2014 but thought it better being posted here, as it describes pretty much what I'm getting with a second-hand V-comp I picked up.

That is, a faint but noticeable crackle/sizzle when the compression engages, even at moderate compression settings.

It has clean power, and I've installed a new tube in case the existing one was on it's last legs, all to no avail.

Using a passive Fender P with flats. Interestingly, the noise is not quite as bad if I put a clean boost in front of the compressor, but I'm not sure whether that's just because the boosted signal is swamping that background crackle.

Has anyone had any similar issues with other compressors, and pinpointed the problem?

Dodgy optocoupler? Failing capacitor? As simple as replacing a pot?

Any help would be appreciated!

 

[tedsalt]

I wouldn't think it's a potentiometer as they typically make noise while being adjusted, when they need to be cleaned. Have you tried just moving the pot to clean it? If that doesn't work, try DeoxIt.

If that doesn't work could be something else.

Has it always been this way? Maybe an incompatibility in your signal chain?

How is the device being powered? Is it on shared power or isolated power?

Good luck!

 

[TwototheValley]

I wouldn't think it's a potentiometer as they typically make noise while being adjusted, when they need to be cleaned. Have you tried just moving the pot to clean it? If that doesn't work, try DeoxIt.

If that doesn't work could be something else.

Has it always been this way? Maybe an incompatibility in your signal chain?

How is the device being powered? Is it on shared power or isolated power?

Good luck!

Thanks for the reply.

Pots turn without any real noise to speak of.

It's on isolated power with a filter (as it's one of those with a quirky 12V AC requirement).

I've moved it around in the chain and used it in isolation, and the crackle always seems to be there, only when compressing notes over the threshold (If I reduce the compression to zero it disappears, even with the make-up gain cranked to maximum). It probably always has been there, but I've noticed it more when I've been playing some quieter stuff, now it's hard for me NOT to notice it.

I suspect it might be a component beginning to fail (?capacitor), or possibly a solder joint. The unit is at least 10 years old, and while in good condition, I'm not sure whether it's been subject to a few knocks over the years.

Still, I'd like to try to fix it as it provides a nice type of compression and is quick and simple to dial in.

 

[yberwaffe]

To me it sounds like a capacitor is going downhill.
Replace the electrolytes first, usually they fail first.