Dennis Had Inspire Amps

[oldtech0]

I have added a switchable regulated/non regulated screen voltage to the PSE mono blocs. output tubes. I can now safely run the 6F6 output tubes on these guys. I also changed out the cathode bias resistors 750 to 560 ohm. Bumped up the bias a few ma.
I am just floored how good the 6F6 tubes sound. I have only used the glass enveloped tubes so far. When I do not see any red plate issues over time I will put the metal cans in. I have also added bias and output tube plate voltage test jacks. That has shown that there can be a 30-40 VDC difference in 5Y3 rectifier tube output. Who da thunk? I also have a bad 5R4GY that puts out 100 VDC less than my other one. Nice to know some of what is happening in the amp without flipping it over on the bench.