Think that might not be an option...that will possibly remain a mystery. The OP should post this amp on various forums to trace the origin of this one.. since it's a pcb amp it should be built in certain volumes, so somebody must know something.zaphod_phil wrote: ↑Wed 04/21/21 4:26 pmWhere's the schematic for whatever amp this is?
Bieworm wrote: ↑Wed 04/21/21 3:58 pmWow.. I think you need to check some voltages. This is with the amp fully dimed?..
The low end is out of balance...
Maybe Josh or someone else here knows where to start looking?
The cathode bypass cap seems rather small..try clip a large value in parallel with alligator clips. At least 1000uf 63V. It's the cap at V4. Watch out for the polarity when testing that... negative to ground
You could have more control over that by reducing the cathode bypass cap on V1, but with the pcb that's a pain in the a$$ when you don't have the know-how and skills
I looked up that OT.. it's 30W??? That's a skinny little iron, no? Maybe what we're hearing is that little one choking on its food? The PT ain't no heavyweight either for that matter. Sounds like this thing is running to its limits