From the blurry schematic I could find for this amp, it appears that the cathodes are grounded, thus meaning this amp is grid biased. Does anyone know the test points I should be looking for to measure the output transformer center tap resistance to pin 3 of the output tubes, and then measuring the voltage drop? I tried the input to the HT fuse, and got some very mismatched readings. Perhaps they are correct and my 5881's are very mismatched, but I'm in over my head a bit on this one.
My measurements are as follows: Left tube (Sovtek 5881WXT) Resistance 69.7 ohms, Voltage drop -2.6 volts, plate voltage 505 volts. Right tube Resistance 69.3 ohms, Voltage drop -1.36 volts, plate voltage 507 volts. From these measurements, I get a plate dissipation of 18.84 watts for the left tube and 9.94 watts for the right tube (facing the chassis from the power tube side).
Why did I buy a Russian amp, lol?