My amp has the SDS cap mod, the old quad cap removed from the circuit, 100uF 160 volt caps in place of the two stock 50 uF caps on the bias circuit. Most of the resistors underneath measure close to original except the two 1,000 ohm resistors between pins 5 and 6 of the output tubes measure 750 ohms. Mine came stock with a small diode where I have seen some MK 3s have a small selenium rectifier. I kept the original Dynaco driver boards and didn't take any measurements there.
1) Are these voltages dangerously high for the amps well being?
2) Will it effect the sound quality?
3) What could be the cause or causes?
Sorry, one more question, I'm thinking about replacing my driver boards with the tubes4hifi boards, how do they sound compared to the old Dynaco boards?
This is a great site, thank you everybody.