Good location for reverb mixing resistor in bassman/marshall like preamp?

[pdf64]

I like that design (especially the 'boing')- have you built it?

[Chuck H]

I like that design (especially the 'boing')- have you built it?

Oh yeah. It was a special request from a customer. The speakers are G12H30's, the PT is a custom order from Edcor and the OT was filched from an old Fisher amp. It sounds great. I told the guy that he has a nicer amp than I do (he thought I was teasing). Because of the highish voltage the bias wiggle trem is pretty much limited to clean tones. It sounds a little garbled as soon as the amp begins clipping. I won't be using bias wiggle trem on such a design again. Otherwise I'm very proud of it. I've never had a Vox amp and that was my favorite "mode" on this build. So now I NEED to build a simpler version for myself. It's on the long list of things I'll get to if I ever have the time and money.

EDIT:
P.S. If anyone decides to build one of these know that laying out the lead dress WRT stability is important. Being somewhat experienced with designing for this I didn't have any problems with my original plan. But I can easily see where it could go wrong if one were at all cavalier about it because the "mode" switch is a single six pole rotary (with a little American flag on side and a little British flag on the other ). Keeping tender leads short and avoiding instability from lead proximity was the primary focus of the circuit layout. With the first triode output, NFB and other circuits meeting at the same switch there's a little dancing to do. Sorry, I never drew up a layout for this one but having it go right on my first attempt means it's not THAT hard.

[tubeswell]

FWIW - Here's the schematic for the amp I mentioned earlier. I've since reconfigured this amp to have a simple AB763 front end (and cut the number of pre-amp tubes to 5 LoL), even though it sounded great in this initial configuration. Ignore the voltage notes in red on this version of the schematic - they are all over the place