OK guys, not my first rodeo but this one has me scratching my head. I have a pair of Coincident Frankenstein-MkII monoblocks. One is dead quiet, one has a psudo 60Hz hum with the amp hooked to the speaker and no input hooked up. Here is what I have tried thus far:
- Cheater plug on power cord to lift ground (no change) If this had worked I would just get a Hum-X and be done.
- Swapped all three tubes between amps (no change)
So if it's not a ground loop on incoming power and not a ground loop on the RCA input (unhooked) what can it be? Possibly a bad filter inside the amp? Anyone have ideas?