Hi and thanks for the tip. After Hot Chili themselves, Analog man (mike) was the first guy I spoke with. He doesn't have them. I also asked if he had at least the schematics, so I could have someone make it for me - I know a great tech in Germany that builds custom gear for me from time to time) - no luck here either and Hot Chili never answered to my request of the schematics.
So I found a guy in the UK, Dave Hall (DHA - Dave Hall Amplifiers). He's building me a custom pedal with a variable plate voltage switcher instead of knob (to switch between 12v and 24v). It will be a twin tube pedal, all hand wired, with tone controls (which the Tubester lacks) and the ability to select channels 1 or 2 independently and combined them.
It will cost me 220 GBP, which is about the same price of a Tubester.
And yes, applying less voltage to the tube plate would produce the same effect EVH used on his Marshal with a variac...Brown Sound.
I own a THD BiValve and it has this feature of hi and low voltage switcher and it's amazing!!!
Dave Hall sells his pedals on eBay. Check it out: Dave Hall Amplifiers - mine will be based on the VT1 Purist.
Ciao!