40, 50, 60, 70% Plate Dissipation on Grid Biased Amps

[TelRay]

hello all,
I was watching this video from Youtube amp repair star Uncle Doug and thought it would provide a good topic of discussion
Basically using the adjustable bias control of an AB763 Fender Deluxe Reverb and evaluating the output with an oscilloscope, audio editor and by ear