I started messing around last week, and worked out some of the Overdrive Deluxe mods, but the Dumble style mods didn't really suit, in this case.
So the way I have it, I can run a triode either before or after the classic Fender : stage>TS>stage, for overdrive, depending on which input is used, and the push-pull pot.
Plugging into the Normal channel automatically puts the extra stage upfront, and plugging into the vibrato channel is stock. A push-pull DPDT adds a stage after, when in the vibrato channel.
Of course the by-product of this mod is that when in the Normal channel AND the switch engaged, you get a stage before and after. I have not even attempted to make this sound good yet
I still need to to plug in the reverb and make sure the vibe works too, but I don't see why not.
The old Normal channel panel pot positions are now gain controls for each triode, and I added a mid/raw pot, which dang near lifts the TS when cranked. Of course I still have both completely unnecessary bright switches to do something with, and in my case, that godawful "boost circuit" on the Vibrato channel Volume pot. Maybe stick a 50K between PI cathode and 470r, and call it half-power. Or maybe put a switch that bypasses the 3M3/10p recovery stage
The MV will be able to be switched in and out once I find a switched pot, and can go in any of the probably available holes in the back. I can get some good Stones tones at reasonable volumes, and this amp will be great for smaller gigs that require a little dirt.
Of course all values of couplers and dividers can be tailored to suit, these just happen to be what is working at the moment.
The only downside is that I had to clip the jumper between ring and tip on the vibrato side jack, in order to feed the signal there....so the input isn't shorted when nothing is plugged in. That's Ok though, because I never play my guitar through the amp when nothing is plugged in!
Cheers- J