Larry Sheehan
Well-known member
This hum is overpowering. Following suggestions, I pulled V1 (12ax7a) and the hum disappeared. I treid swapping in other 12ax7s I had and which don't introduce hum used in V2 socket, but the hum persists.
I have a schematic, but it's larger than the 300k limit to post here. I can read schematics, albeit slowly, have a good head for debugging, and have a multimeter and scope.
The amp is on a pc board, but by tracing from the tube sockets I should be able to follow a signal along.
I believe I have ruled out a bad V1 tube. I don't know where to look next. Any suggestions? I've got sense enough to work safely in the chassis and I really believe I can learn something valuable by shooting this bug. All help greatly appreciated.
I have a schematic, but it's larger than the 300k limit to post here. I can read schematics, albeit slowly, have a good head for debugging, and have a multimeter and scope.
The amp is on a pc board, but by tracing from the tube sockets I should be able to follow a signal along.
I believe I have ruled out a bad V1 tube. I don't know where to look next. Any suggestions? I've got sense enough to work safely in the chassis and I really believe I can learn something valuable by shooting this bug. All help greatly appreciated.