Tube Amp Archive

yeah, that's just the camera angle making it look like the NFB wire is grounded.

The OT secondary ground is the black wire going to the left side of the speaker jack - the grey is the 16 ohm tap, green is 8 ohm, and yellow is 4 ohm

the OT is actually grounding at the speaker jack - the white wire you're referring to is the NFB wire

i had to let this project sit a while to keep myself from getting too aggravated, but here's some more info finally: It seems that the problem is somehow tied to the negative feedback circuit - I can either disconnect the NFB wire or cut the presence pot to 10 and the oscillation goes away. I'm gues...

Thanks much for the replies! In response: I have tried different power and preamp tubes I have tried reversing the OT leads - it squeals like mad when I do that. I've gotten my lead dress as short and neat as my chassis will allow also I've tried grounding R3 at the tube socket with no change. Also ...

Hello all, I've been trying to solve an oscillation problem on my 2204 build for the past 2 months with no luck. The Problem At low volume (below 2 or so) the amp sounds perfect; once the Master Volume passes that point there is a bad unnatural distortion/buzz when a note is hit - it is noticeably w...