[dr_daw]

Hey gang,

So about 14 years ago I built a Paia 2ch tube pre kit. I used it for a year or so, then two things happened; I started to notice that signals were only distorted in the negative swing on CH 1, and I accidentally applied phantom to the outputs (as the pre was connected to an analogue mixer that had PP across all channels). At the time I didn't have a function generator so I wasn't able to troubleshoot.

I did find a few blown caps from the 48v hit, changed those out years ago.

I have since become obsessed with this old project since I repaired a function generator kit. I've been trying to figure out what's going on with both channels for the last few days. Ch 1 mostly works; but it still only distorts in the neg swing of a 1kHz sine wave (through the tube drive section). Ch 2 on the other hand seems to be having an issue with the tube drive section not functioning at all; as well as no PP or Drive LED.

I know this is a weird thing and not many are likely familiar with this kit. I do know that there are some of you out there with more electronics training than myself. I have traced the signal through the circuits and can't quite isolate the issue.

On CH1, I'm guessing some form of DC offset is being introduced by a damage component. On CH2, I'm guessing the caps weren't the only thing that got damaged from the 48V hit to the output section.

Thanks guys...