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Amp Issue

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Posted on August 14, 2020 at 14:05:37
Stuben
Audiophile

Posts: 654
Location: Guber Ohio
Joined: December 30, 2005
Contributor
  Since:
May 22, 2009
Guys,

One of my builds has developed an issue. After some time in service, one of the channels goes 100% with the volume at 0%.The other channel sounds slightly distorted.

I do do have CCS feeding the plates of the first stage. I can't imagine a POT failing like this or it would be that way when it's cold. Could I be getting imbalance due to not enough isolation between channels. I presently have a modest amount of resistance between the b+ each CCS. I have considered diodes to isolate the B+ for each CCS.

Any thoughts?

Stuben

 

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RE: Amp Issue, posted on August 14, 2020 at 18:54:20
Paul Joppa
Industry Professional

Posts: 6991
Location: Seattle, WA
Joined: April 23, 2001
I can however easily imagine a marginal solder connection to the ground leg of a pot failing in a temperature-sensitive way. Just sayin' ...

 

RE: Amp Issue, posted on August 15, 2020 at 05:54:27
Stuben
Audiophile

Posts: 654
Location: Guber Ohio
Joined: December 30, 2005
Contributor
  Since:
May 22, 2009
Thanks Paul,

Yea after the post, I thought some more about heat. I have had heat issues with position I placed the amp, in furniture with little head space. I've also had funky heat related issues in the past with CCS mosfets. They are great loads but can be a little sensitive. I will check my pot connections and others and move the amp.

Stuben

 

RE: Amp Issue, posted on August 15, 2020 at 10:10:26
Stuben
Audiophile

Posts: 654
Location: Guber Ohio
Joined: December 30, 2005
Contributor
  Since:
May 22, 2009
Checked the connections and one channel is open to grid to ground on the pot. Nice sounding AN pot. Looks like the pot connection has failed. I was able to wiggle it around and get some continuity to ground.


Thanks

Stuben

 

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