Harse hum from 2:90?

[RBoogN]

I just bought a used 2:90.With the volume all the way down on my guitar my ADA really humms loud! I plug back into my 2:95 and its fine.The noise effects both channels.I pulled off the cover and tried new p/a tubes & nothing.I noticed in resistor slot R101 there are two resistors soldered together and directed into the board???Is this normal?I havent seen any thing like this or heard it as well???

 

[Gregwor]

You might just have a ground loop problem. Try ground lifting your units or purchase 1 or 2 audio line transformers and place them at the power amp end of the cables (going into the power amp 'in').

Also, to eliminate the power amp as being problematic, plug your guitar directly into the 2:90 and switch the input sensitivity to 'instrument' and see if the power amp still buzzes/hums. I suspect your power amp is ok and it is just a grounding problem.

 

[RBoogN]

Thanks for the reply.I will try this tommorow.I cant really shitkick the neiborhood tonight.Although Id like too.