Here is the schematic I’m working on. It’s subject to change but I think this will be the general idea. I’m trying to keep it an 18 Watt Marshall sort of thing.
It a cascaded first tube, just real basic with a coupling cap and volume knob.
The tone control might look a little different but it is Marshall in origin. That tone control is from the Marshall 2046 Specialist. It’s a little off the beaten track Marshall model that, apparently had quality issues but it’s tone control works pretty well and sounds good. Here is the Specialist schematic.
The other thing I’m experimenting with is the PPIMV. I was trying to make the master volume sound better as it is turned down. I got the idea to look into what guitar players were doing to improve the sound of guitar volume knobs as they are turned down. I saw that adding a resistor and cap in series was a popular mod. So that’s what i tried and it sounds really good. I’ll probably leave the master volume alone.
Probably the main thing I’m looking to tweak is the split load resistors on the second stage. I feel like I need to fine tune how much to drive the phase inverter and output tubes.
Hey, DNATOR! I know this was posted a long time ago but I came across it looking for EL84s in use. And here you are. You might not remember me. It was longer ago when I started tinkering, with you help, with my Crate V33. That got my interest rolling and I built an AX84 kit. Now I have 3 amp designs of my own and a thriving sales and repair business. I am Activax Amplification (@gmail). I’d like to thank you for your patience and help, I do owe you for that.
Your amp here looks nice. I have one with a similar power amp but my preamp is pretty different. I like this design partly because I favor using PPIMVs; all my amps use them in one way or other. My customers like them too, after they see how they work in my boxes.
Anyway, just wanted to say howdy and Thanks after all this time. And to give this design a thumbs up.
Ken Graves
Hey Ken, I saw your comment on the Rockhead video and thought the name looked familiar. Congrats on the amp business!
My old V33 has been sitting under my bench for years and years. I keep thinking I’m going to do something with it one of these days…
This particular amp has been reworked but I agree on the PPIMV, they are pretty handy.