Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Koop on November 21, 2018, 08:44:49 AM

Title: Right channel hum and imbalance.
Post by: Koop 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?

Title: Re: Right channel hum and imbalance.
Post by: Paul Birkeland on November 21, 2018, 09:51:03 AM

Quote from: Koop on November 21, 2018, 08:44:49 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?

Title: Re: Right channel hum and imbalance.
Post by: Koop 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.

Title: Re: Right channel hum and imbalance.
Post by: Paul Birkeland 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?

Title: Re: Right channel hum and imbalance.
Post by: Koop on December 03, 2018, 12:18:25 PM

No i did not.  I Might just order a new pot and try that instead.