Here's from Craig at Eddie Current:All Moth amps had manuals with schematics. If you got the amp it should have been sent in a wooden crate with the manual. That amp is 17 years old and it is likely the electrolytic caps are dried out which would account for the buzz. I don’t have any documentation on the Moth amps, and don’t work on them.You need to measure the bias resistor to see what the bias voltage should read. The 45 tubes need about 36mA, so if the resistor is 1 ohm the meter should read 36mV. Make sure you have the correct tubes, I have not seen a 45 tube that looks like that.