Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: rundgrenrules on June 30, 2022, 12:51:30 pm

Title: Check My Work - Non-Reverb Princeton Bias Balance
Post by: rundgrenrules on June 30, 2022, 12:51:30 pm

I just posted about adding a bias balance pot to a 5e3, and here I would like to do the same to my Princeton. Since the Princeton already has an adjustable cathode bias, it should be a much simpler affair. I will need to add this AFTER the Intensity pot so I can keep the bias-wiggle tremolo. Does my wiring look correct for use with a center-tapped 10k pot?

Thank you!

Title: Re: Check My Work - Non-Reverb Princeton Bias Balance
Post by: sluckey on June 30, 2022, 01:34:46 pm

Looks doable to me. Easy enough to try. I wonder if/how the tremolo strength may be affected?

Title: Re: Check My Work - Non-Reverb Princeton Bias Balance
Post by: rundgrenrules on June 30, 2022, 01:56:14 pm

Well, I am coming from a JJ 6V6 pair and using one of two pairs of old RCA tubes that are less-than-matched (15mA idle current difference).

I'd like to use these RCAs and get rid of the comparatively 6L6-ier sounding JJs, and would like to just be able to use any pair of tubes I have on hand (matched or un-matched). 

I am going to pop this in and give it a shot this evening.  I would THINK that the bias vary tremolo would be preserved since this is placed downstream of the Intensity pot and keeps the two power tubes separate from that point.