I have been rebuilding a Sound Valves M60 monoblock amp. The power supply needed quite a bit of work, and while I was at it I replaced many of the smaller electrolytics. In getting the amp working again I discovered an adjustment pot in the preamp section, but no instructions for how to set it properly. I'm attaching the schematic and the pot is P1(20K) on the 12AT7. In other amps like this there were identical value resistors used in the plate circuit and the cathode circuit. I could just adjust the pot so that the plate and cathode resistance values are identical - but it seems like they could have done this with fixed resistors in the design. So it seems like there is some other reason for this adjustment.
I have searched for info on the Sound Valves amps and how to adjust this pot, but can't locate anything.
I'd appreciate anyone who has experience with this particular amp or this type of amp to give me some insights on how to make this adjustment.
Thanks.
I have searched for info on the Sound Valves amps and how to adjust this pot, but can't locate anything.
I'd appreciate anyone who has experience with this particular amp or this type of amp to give me some insights on how to make this adjustment.
Thanks.