2:ninety humming

Triaxis, Quad Preamp, Stereo Power series, Recto Preamp

Moderators: Guitarzan, Grandor, ned

Post Reply
kilgoretrout5447
Bottle Rocket
Posts: 3
Joined: Tue Oct 24, 2017 11:20 am

2:ninety humming

Post by kilgoretrout5447 » Fri Nov 02, 2018 12:57 pm

Sup gents. I just picked up a 2:ninety with issues for dirt cheap, and I am having trouble killing the hum. Hoping another tech might have run into this. There's threads out there, but none seem to have the answer. It is waaay worse on channel A, but slightly present on channel B. It goes away when you turn down the level control. I have swapped all of the tubes around, and tried new tubes on both channels and preamp. I recapped the power supply. Not the bias caps though. When I scope the input of channel A at the jack, it seems clean, but at the other end of the wire, I get sort of a clipped half wave 60 hz ripple. Bias caps? But that would affect both channels equally right?
Only other place I can think to check is the 10k uf 16v caps in the switching matrix. Has anybody run into this?

Post Reply