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Noisy volume pot after recap

rstloup

rstloup

pfm Member
Hi everyone,

I recently got my 42/110 recapped. When I plugged it in after repair, I immediately was hearing some painful distortion on the highs on familiar recordings so it went back to the repair person to see what's wrong. One other thing that did occur after the recap though is that the volume knob started to make a hissing noise when you adjusted the volume. The person fixing the amp suggested it was likely a dirty volume pot. He hasn't explained to me yet -- or at least not very clearly -- how the pot wasn't making noise before the recap but is now. Do you all have any thoughts or experience with this?
 
I suspect he made a mistake fitting one of the caps, unlikely to be the pot.

He will probably magically fix it.
 
If DC gets on the pot it will crackle or rustle. Anyway, a recap should be followed with a few hours burn-in and then a full functional test. You sure this repairperson is competent with audio gear?
 
MJS said:
Sounds like DC on the wipers. Someone got the tantalum capacitor polarity wrong.
Click to expand...
This or dust that’s been spread inside the pot. The cure for the latest is to clean and lube with proper stuff and/or turn the pot up and down to both ends back and forth about 30 times to wipe off the dust.
These pots are usually so high quality that they rarely fail.
 
Probably DC on the wipers yep. If it hasn't cleared over maybe 24 hours tops then the capacitors are faulty or fitted the wrong way round or an unsuitable type such as Oscons (or other organic polymer type) have been fitted.
 
The person who did the repair is reputable here+ was recommended. The suggestion about DC on the wipers is something I passed onto him. I think something just went wrong and hopefully it can all be fixed.

One other question, the other thing I noticed after recap was a difference in how I ran the volume on the amp. I usually was at 1/4-1/2 through the volume knob but 1/4 up after the repair was incredibly loud. Is this normal?
 
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