Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pbman1953 on October 19, 2015, 09:16:04 pm

Title: Bias pot for a Peavy classic 30 or delta blues amp
Post by: pbman1953 on October 19, 2015, 09:16:04 pm

Has anyone done one before?

Easy install?


Worth it? Or just buy the right tube set

Title: Re: Bias pot for a Peavy classic 30 or delta blues amp
Post by: sluckey on October 19, 2015, 09:29:20 pm

Both look straightforward on paper. Just replace R63 with a 50K pot and replace R64 with a 22K resistor.

Title: Re: Bias pot for a Peavy classic 30 or delta blues amp
Post by: pbman1953 on October 20, 2015, 06:53:35 am

Is it worth it to do it?

Title: Re: Bias pot for a Peavy classic 30 or delta blues amp
Post by: sluckey on October 20, 2015, 08:26:04 am

That depends on how accessible R63 and R64 are. They are likely mounted on a board. This style pot would probably fit the board nicely and be easy to adjust if the board is easily accessible. I used this Bourns trimmer on an old Harvard. Or you could always drill a hole in the chassis for a panel mount pot.

I think it's worthwhile to have a bias adjustment ***IF*** it's not too difficult to actually install the mod. I can't make that call on those Peavys without seeing them.