Live he has been using UL's striaght out of the box. Back in the 90's, he used a Kolbe head and preamp in a wet/dry setup.
If I'm not mistaken, he had the Kolbe GP1 preamp and a modded 2204 into his Kolbe ported 4x12's. I use to have a few pics of his rig from backstage...
I just found this from an interview with him in Guitar Player....
"How do you get your sound?
I’m trying to keep that process simpler these days, so I’ve been using the same rig in the studio that I use live—two VHT Ultra-Lead half-stacks loaded with Eminence speakers, and a Harry Kolbe preamp. My effects include a DigiTech Whammy, a Tech 21 XXL, a Prescription Electronics Outbox, an Ibanez TS9 with an 808 mod, a Boss NF-1 Noise Gate, an MXR Blue Box, an Analog Man CompROSSor, a’74 Vox wah, a Roland volume pedal, a Korg SDD-2000 digital delay, and a VHT Valvulator. My big, special secret right now is the Boss RV-5 Digital Reverb set to its Modulation setting.
I’m still using custom ESP Horizon guitars with the Floyd Rose systems, because my new signature ESP models with DiMarzio Airzone pickups haven’t had the chance to settle in with the dropped-D tuning. I’ve been using D’Adarrio strings forever—a .010-.052 set. I use thick, Clayton 1.52mm picks, because I have a nerve-damaged thumb from a run in with a beer glass, and I need that thickness in order to feel them."