I'm pretty sure (at least from all the interviews with people who were there) that Jose was like the best amp tech available, and EVH availed himself of him.
Tried a master volume, didn't like it, so jose took it out. Jose taught him how to set up his amp with the dimmer switch and blah blah.
The "extra super special secret" is a great marshall that's got great tubes and is running at 83 or whatever the fuck it was - just a superlead/plexi circuit matched to a great player.
People don't want to hear that. They want there to be a magic secret that makes their garbage boomer playing sound like EVH. I honestly think most of what they think is the Legendary Brown Sound (trademark) is just a superlead and greenbacks and a player playing alot of major sounding chromatic passing tones over blues with a 6/8 swing.