George - How about a Tom Scholze Power Soak? Have one I never use, don't need, (it won't work at 2 ohm and don't need it with the Super Reverb anyway) Don't need it for the MX, so it's gathering dust.
One thing to remember though, those things can be tough on transformers. The one I replaced in my MX was $125 around 10 years ago. And that's soldering it in myself, plus $35 to have someone test the transformer so I could be sure that was the problem. The power soak didn't fry it, I think a bad speaker jack did.
A tube amp with no load can fry a transformer. So one night at an audition I didn't know the speaker jack was way loose, the amp sounded really nasty, I switched to the Super Reverb. Glad I brought it, I didn't know if the MX would work at all, it had been acting flaky. So the speaker jack was popping in and out really fast when I played, speaker on and off a lot, next day I had a garbled sound no matter what volume level, the amp had always been super clean...
Anyway I don't need the Power Soak, been thinking about selling it...
JW - I've never used one, thought about building one a while back and using the Champ to drive it, never did though. To use it you just mouth what sound you want, words included, and it plays back through your mic. the tube carries the sound from the amp or voice box, that is shaped by what your mouth does, "reflects" back into the mic. They say it feels weird at first. I did a lot of reading up on them, a small amp, horn driver and plastic tube can be used to build one, A/B switch for when you want to use it, and all I would have to do is unplug the speaker in the Champ, plug in the driver and hose, and no modifications to the amp at all.
Still might at some point, but I would have to figure out how to swap things around, since I now use the A/B switch to run through both channels of the Super Reverb. Normal and Reverb channels have different sounds, and Normal channel is louder for leads, it works out great. But that would mean a hasty swap if I wanted to run a voice box made from the Champ. Should be a quick and simple one though, unplug from one channel of the Super, plug the same cable into the Champ.
I dunno...might find another horn and try it sometime. The horn I had got lost in the shuffle somewhere between here and Louisiana and back...
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