Jet City 20 bias pot bad

[M Fowler]

Was at my guitar store and they sent this Jet City amp home with me for repair.

The bias pot would go in and out. If you touched the bias pot with chop stick it would work. Tried resoldering but the problem was the bias pot was loose and just poor quality. (50k bias pot)

Replaced that with a 47k I had on hand and then metered it. 382v to the plates and I set it to 21mA. Screens were 361v.

I like the crunch channel and it gets loud.

Mark

[xtian]

Look like decent traces on that PCB, huh?

[M Fowler]

Yes I thought the amp was solidly built with good traces. I don't are for the input and speaker jacks on PCB that will be the next fix I'm sure.

[Reeltarded]

Friend has one of these with the clipper circuit off a Jose schematic.

Thumper! I like 'em.

[M Fowler]

Did that make a big difference in the amp? These amps seem to get to a good distortion level but then nothing more after that. I still liked how it sounded.

I don't think I have that clipper Jose notes

Mark

[Reeltarded]

I will ask where the diodes ended up, but I think just opposing transistors off the master INPUT to ground was where it was when I liked it best.

If you put it on the output the volume controls how much. I like it to be an integral part of the sound on the input side.

[M Fowler]

The local music store said this is the third amp with a bad bias pot.

Mark