Wondering on how I could modify a stock ST-70 so I could adjust the bias on each output tube individually using a "balance" pot similar to Shannon's design? I understand the circuit needed to measure the current on each tube, can copy that off my diytude board design.
What I am looking for is info on if a 10k or 20K linear pot can be used to adjust the current from side to side? Basically I want to come off the existing pot and go into a second pot that adjusts the ratio.
Any ideas or suggestions guys? The chassis I got was already drilled for the extra pots and I like the idea of balancing rather than trying to adjust 4 tubes individually.
I don't trust the "matched pairs" I buy today to stay matched for long!
Thanks,
Ed the Solder Slinger