ampdoc1 - that looks really similar to something I'm just planning out, how neat.
I'd love to hear some of your experiences with trials of that build.
My idea might be a bit different, I'm building into a silverface bassman and am thinking that the bass channel will be tweed bassman and normal channel will be the ODS lead.
Then, I'm going to add a switch to express-ize the tweed bassman side in some manner - this is the part I haven't quite settled on but I think you had a similar idea.
The reason my thought may be different is that I don't want a pure dumble tone, and the express tone doesn't have to be pure express either. I like dumble leads when the "clean" side has a bit of grit (pab on, turned up) so I don't think I'd do the changes in EQ and power section. Did you feel this was really needed? When you used one EQ which one did you use?
Were you able to get reasonable volume levels between the multiple parts? That is the part I've been racking my head around. I feel like I can do what I want to do but that the express part will just be overly loud compared to others.
The amp I built used the Express EQ values, but you will notice that throughout, I have used a lot of different combinations on the plate and grid resistors/caps, This was done stage by stage using my ears. But, easy to change to taste.
My design lets either EQ channel to use the Dumble OD or not. Not really necessary to have both, I just wanted to have a couple of EQ choices. All in all, the mix/tone of the amp is very easy to set for either clean or OD, and the Trainwreck values sound great with the Dumble OD. The values I show here for the alternate EQ channel is from a Roland Jazz Chorus, but, a lot of other choices could be easily substituted, or just use one EQ as my original amp did.
The tone was very, very good. The amp retained the TW pick sensitivity with or without the OD section, and the OD just added that smooth-ness and "bloom". No problems with setting the controls to get great sounds between clean and OD. Basically set the clean signal for the required tone/volume level, then adjust the OD input and output to taste..
Volume wise,.. this is a ~40 watt amp. If you want less volume, incorporate a smaller power amp design, or add a VVR.
