IIRC, Dave Weyer was the tech at West Coast Organ & Amp that did a lot of work on Jimi's gear. It'd be fair to say he did as much, if not more than the more commonly known Roger Mayer in the way of modifying Jimi's gear, stuff like replacing Marshall transformers with bigger, non stock units so as to run the (power) amp in straight class B etc. Head on over to the Metroamp forum & check out what he has to say (Jimi Hendrix forum). Goes into detail on a lot of stuff, how he modded Fuzz Faces, wah's etc. Some interesting reading in a few different threads. Cheers