Right channel hum and imbalance.

Koop · 1384

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Offline Koop

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on: November 21, 2018, 08:44:49 AM
I upgraded the stock pot to an ALPS blue velvet. I am experiencing some slight channel imbalance shifted to the right. More bass resonance and rumble than the left. Also , the with pot maxed out to full there's no humming, however when i back it off to any other value there's a low hum in the right channel. I've checked all the solder points and my measurements are accurate to what is stated in the manual. Is this a tube related issue?



Offline Paul Birkeland

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Reply #1 on: November 21, 2018, 09:51:03 AM
I upgraded the stock pot to an ALPS blue velvet.... Is this a tube related issue?
Did you listen to the amp with the stock pot first?  Did you mount the Blue Velvet to a PC board?  From which vendor did you buy your Blue Velvet?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Koop

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Reply #2 on: November 21, 2018, 09:57:36 AM
Yes. I originally bought the amp second-hand without Speedball installed a few years. I installed the speedball upgrade and all was good. About a month ago I took the entire amp apart and rebuilt it as it was starting to become noisy and wanted to paint the Chasis and base anyway. I bought the pot from Parts Connexion. 100K. I did not mount it to a PC board.



Offline Paul Birkeland

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Reply #3 on: November 21, 2018, 01:07:23 PM
It's a PC board mount pot.  When you mount wires right to those pins, the wires will tend to pull too hard on them and you'll damage the pot. 

Did you do a voltage check when you rebuilt your amp?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Koop

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Reply #4 on: December 03, 2018, 12:18:25 PM
No i did not.  I Might just order a new pot and try that instead.