Re: Vai using JCM 900's
I've seen video of him using the Legacy drive pedal through a Marshall stack before. Kind of indicates his tone being primarily preamp driven I suppose, with the head only serving as a PA to drive the speakers. Its probably just that they are just a commonly available amp in various locations. Orange does seem likely as they are a bit on the dark sounding side, which balances out with EVOs. I'm going to Generation AXE at the end of the month, so it'll be interesting to see what he's running there.
RG 2550 w/ evo2 breed neck
SZ520 paf pro neck stock bridge
Marshall Haze 15