I'm having some issues with this amp. The master volume is scratchy and and fluctuates between a weak signal and full volume unless I fiddle with the knob and get it to the "spot" , similar to an iffy radio station. Also, boost foot switch and effects loop don't work. Are these fixable issues?
This is a fine amp, and has been killer at my shows. At worst I could salvage it for the speakers, but I'd really like to get it working again
The scratchy jumpy volume sounds like a potentiometer that needs to be replaced, easy fix for a tech.
As for the fx loop, it is line level, not instrument level, meaning it was designed to work with Pro rack gear (+10db) rather than traditional stomp boxes(-4db).
I'm not sure what is your issue with the
boost/fx loop exactly, but in theory all fixable regardless of the issue.
Did they use to work?
Have you had the switch set to footswitch rather than normal or boost on the front panel?
Have you tried replacing the relevant preamp valves for boost and fx loop?