Adam Jones

In this diagram, it shows Adam using a Dual Rec as part of his guitar rig.

This YouTube video features DunlopTV and their interview with Adam Jones's guitar tech since 2001, Chris "Frank" Leahey who points to the Diezel (4:18s) and says, "And these Diezels which are insanely loud."

In an interview for Guitar World magazine, Adam said, "Right now, for my live setup I’m using two Diezel heads and an old vintage Marshall bass amp that’s been hot rodded. The good thing about the solid-state stuff is if you know what you like, you can go to any store and buy exactly that. But with the tube stuff, you gotta find the amp and hold onto it. I’ve never heard two Marshalls that sound the same"

In this image of Adam Jones of Tool performing live, two Diezel VH4 100W Tube Guitar Head Amps can be seen.

This article from Gibson's website suggests that Adam Jones experimented with using a vintage Sunn "lead" head in the studio when recording Lateralus

Live and in the studio, Jones uses a blend of amps. Two favorites are a 1976 Marshall Super Bass and a Diezel VH-4 “blueface.” On the latter, he never switches out of the ultra-high-output third channel. During the recording of 2001’s Lateralus, he reportedly experimented with a vintage Sunn lead head, too, and for 2006’s 10,000 Days he blended his Super Bass and Diezel with a Bogner Uberschall and a Riveria Knucklehead. Jones drives all his amps hard to achieve his responsive tone. He also uses Mesa Boogie Dual Rectifiers and Marshall and Mesa cabs

Live and in the studio, Jones uses a blend of amps. Two favorites are a 1976 Marshall Super Bass and a Diezel VH-4 “blueface.” On the latter, he never switches out of the ultra-high-output third channel. During the recording of 2001’s Lateralus, he reportedly experimented with a vintage Sunn lead head, too, and for 2006’s 10,000 Days he blended his Super Bass and Diezel with a Bogner Uberschall and a Riveria Knucklehead. Jones drives all his amps hard to achieve his responsive tone. He also uses Mesa Boogie Dual Rectifiers and Marshall and Mesa cabs.

In an Instagram story from Adam Jones' account, he showcases a Mesa/Boogie Mark VII Tube Amp Head. The video begins with a close-up of the amp head and then zooms out to reveal the head is sitting on a Recto 4x12 straight cab with a custom grey grille cloth on a podium, before panning towards an empty venue. The accompanying text indicates that he is conducting a soundcheck for a gig, suggesting the amp's use in his live setup.