So I've got a 4 channel pre with scratchy sounding pots.
The volume pot on my Command 8 is scratchy on the right speaker.
One of my API 312s needs to be pounded on to stop hissing and spitting.

Is there possibly a simple solution, i.e. blowing some compressed air in 'em, or some lube of some sort?

Or something else I can do first before I have to send them to a tech?

Turn the knobs aboout 50 times. All the way. There is dirt in the pots.

You used to be able to get tuner cleaner from radio shack - you know that CFC based solvent and lube/protectant stuff.

I bet there's a replacement

I bet it isn't quite as good.





-tINY

Kris,

One other cause of scratchy pots, besides them being dirty, is a bad series coupling capacitor that's letting some DC get through. So if cleaning or exercising the pot doesn't solve it, that's the next place to look.

--Ethan

It seems like I've posted an answer to this question a hundred times over the years.
Rather than another, here's a similiar post I made some time ago.

https://www.gearslutz.com/board/showpost....99&postcount=4


Regards,

Vince Poulos
Pot & Switch Cleaningmeister

Thanks for all the responses. For the record, I did try the search function first. I love my Speck gear!

Just grabbed the 5% FaderLube in a mini-spray can, and the 100% Faderlube in a needle dispenser bottle direct from http://www.caig.com./ . Bingo!

Caig makes something called "Faderlube", huh? That's interesting, and good info. All the Caig products I've used have really worked well.

I was about to suggest Caig De-Oxit for the scratchy pots. Good stuff, even better than the old RadShack tuner cleaner. But I'd have to assume something called "Faderlube" would have that name for a good reason.

Faders->spray with oil.
For contacts->Spray without oil.

If you’re up for it you could try putting the modules in an ultra sonic bath, similar to the ones used to clean jewelry. When I worked at Cello we cleaned every single Neve and API module we had in house. (I still have nightmares about getting through all of the modules.) We even put the patch bay in Studio #1 in the bath. Everything came out squeaky clean with only the occasional problem. I think 3 or 4 modules out of 300 had problems. The patch bay had one point that had to be fixed. If you’re interested let me know and I can give you the recipe.

If the pots are sealed, that won't do any good... no matter now much stuff you spray at it.

This is known as 'excercising the potentiometers'.

But the cause is generally not dirt, but rather oxidation. The contact surfaces obviously cannot be coated with anything since that wouldn't allow proper contact, so if a potentiometer stays in one position all the time, the area where the sweeper isn't in contact can get a build-up of oxidation. Especially in humid climes.

When you exercise them, you're trying to get the sweepers to clean the contact surface.

If that doesn't work, you might want to try exorcising them.

Just a followup... The faderlube rocks. Works great.

I just ordered the faderlube as well. This thread really should get a lot of play with all the old analog consoles in this place.

Tetrachloroethelene cleans pots will not conduct electricity. This is the best contact cleaner out there.
But is causes Cancer!!!

Really dirty equipment can be partly disassembled and put in a home dishwasher (without the corrosive detergent) for a 90+% good result. Hot water works great. Turn off the hot element dry cycle and let it air-dry. This was/is standard treatment for tube Tektronix oscilloscopes full of diesel soot and fuzz.

Carbon Tetrachloride used to be the best no-residue cleaner ever. Causes cancer. Even more fun is if you put Carbon Tet in your ultrasonic cleaner: Phosgene (WWI toxic gas). Most ultrasonic cleaners have a warning sticker about this. So stick with recommended cleaners in the ultrasonic bath. Water is safe, and isopropyl alcohol is a decent degunker in an ultrasonic tank. Fortunately for the unthinking is that Carbon Tet is just about impossible to get. I'm hoarding a quart for "last resort" small cleaning jobs, in the same spirit as vintage DDT powder.

Cheers.