Help with bias voltage, it's too low

[elegost]

That voltage should be a lot more than that! I think you have the primary of the PT wired wrong or if you're using the voltage selector shown on the schematic I think it's set for 220V.

Check the other voltages from the PT What do you have on each filament lead in respect to chassis? If it's also low them that really points to a primary side wiring error (or wrong switch setting).

This would also explain the bias voltage being so low.

Ok i will go through the wall to PT wiring again. That must be the problem area because i just made an all new bias rectification setup on a breadboard with all new resistors, diodes and caps based on mhuss's schematic and i'm getting similar results.

[elegost]

Ok mystery solved, the mojotone layout has the 120 and 240v leads swapped on the voltage switch and I blindly followed it. I really should have caught this.

Thanks everybody so much for your help!

[Reeltarded]

REVERT the circuit BEFORE starting the amp..

Right.. just sayin'...

[elegost]

Yah I moved the bias supply tap to before the standby switch.

I think I'm going to mail Mojotone about fixing the errors in their layout for future noobs like me. Maybe the jcm800 is not popular and that's why no one has caught them.

[Reeltarded]

Those emails go to their spam folder. You wouldn't be the first.

[rp]

That pict of you holding both probes w/ one hand scares me, I know you needed the other hand to take the pict, but really, get yourself a set of these so you can clip to the chassis or ground.