Something I noticed while putting the reverb pot back into the circuit is that previously it was wired incorrectly -- the wiper lead was hooked up to the 3nF cap rather than the 470K resistor (and vice versa). Which might explain why I was getting some weird oscillations with the reverb pot in my earlier experiments.
Thanks for sharing the link! I didn't know that Brad's Guitar Garage was a youtube page -- I misread angelodp's post and thought he was recommending I send the amp to Brad to rebuild. But very cool that he's doing instructional videos, I'll check it out. I've already watched basically everything Uncle Doug has done, so I need some new bedtime TV.lonote wrote: ↑Thu Nov 21, 2024 11:48 pm After looking more, I would be inclined to do as @angelodp mentioned earlier & strip/rebuild the board.
Not sure if you are aware of the YT videos by Psionic & Brad's Guitar Garage (previously mentioned)..? They have any number of relevant videos, & this one especially fits the bill. https://www.youtube.com/watch?v=KYs0beb3l1w
For the time being though, I'm happy with how the amp is sounding. Next steps will be to get the reverb RCA jacks sorted, hook up the original speaker, and read up on the bias vary tremolo circuit. Thanks again everyone for your help!
Posting the current voltages for posterity, and in case anyone is interested. Still higher than stated on the schematic, but within the +/-20% range.
B+ 442
V1
1 ) 176
2 ) 0
3 ) 1.62
6 ) 172
7 ) 0
8 ) 1.56
V2
1 & 6 ) 423
2 & 7 ) 0.02
3 & 8 ) 8.44
V3
1 ) 184
2 ) 0
3 ) 1.39
6 ) 183
7 ) 0.04
8 ) 1.52
V4
1 ) 258
2 ) -0.8
3 ) 2.56
6 ) 220
7 ) 24
8 ) 69
V5
3 ) 439
4 ) 431
5 ) -39
6 ) 0
V6
3 ) 439
4 ) 431
5 ) -39
6 ) 0
