Line6/Bogner spyder valve hum.

[catstrat]

Spider valve

Hi Jazz P. It is a spider valve hd 100. Let me run a signal into the pwr amp in jack and see what happens. I did replace the bias filter cap and the bias diode for grins and then i set all the bias pots to the lowest bias voltage i could get at-52 volts. Tested it with o/p tubes in and now i have 430 plate volts which is where i would expect it. I think i'm on the right track. I installed the 2 p i tubes and one tube has higher plate voltage then the other. Maybe a shorted tube. The hum is still there but not as bad. My effects board voltage is now at +/- 10.2 volts. I'm going in the right direction. Thanks.

[catstrat]

I ran a signal into the power amp in and the o/p was clear and strong, No hum at all. Signal into input jack and it passes signal but still has a bad hum.

[Jazz P Bass]

The schematic is here: http://music-electronics-forum.com/a...00-scheme-.pdf

By going in the Pwr Amp In jack, you are bypassing the preamp.
The 'hybrid' part.
More like a computer.

Forget the PI.
The plate resistors are different values (200K, 82K).

[catstrat]

Thanks everyone. I spoke with the customer and told him it's best to let line 6 deal with it. I do not work on digital period. I determined the hum is in the preamp section. Before i can successfully fix something , i have to be clear on how it works. Digital electronics is something i don't care to tackle. But the Gallion Krueger is back on the bench though. I'm just a gluten for punishment.

[Jazz P Bass]

It's a shame that you are bailing without even 'looking' at the various preamp power supply rails.

On the schematic first page, it shows the the input jack board and on it you will find a buffer opamp & the +5Vdc & -5Vdc rails.
The board header can be lifted to see if this affects the hum.
If it does, then you have narrowed it down already.