Geezer Butler and his bass tech, Terry Weity, gave a close-up look at the new bass rig Geezer's using on the road with Black Sabbath. Backstage in the Air Canada Centre, they talked in depth about the amps Geezer uses, and how he gets his humongous bass sound. At the center of Butler’s massive bass tone: a massive bass rig.

Weity gave a run-down of the bass amp set-up. It consists of four 500 watt Hartke Kilo heads all running at once. Weity said the amps’ graphic equalizers help him shape Butler’s tone. He also said the amp generates great distortion. Butler loves the amp’s distortion, adding, “It’s a good distorted sound, and you can control it, have as much or as little as you want without blowing the amps up. It’s great.”

The bass tech mentioned that the Kilos can each run two speaker cabinets at once, and a blend knob controls the mix of the two different cabs, which gives Butler even more control over the bass tone. He uses each of the amps to run two speaker cabinets, with two amps running each running two 4x12 cabs and the other two each running two 2x15 cabs. Considering how high he sets the gain and volume on the amps, Weity said Butler’s definitely taking advantage of the amps’ considerable power. All the eq frequencies he keeps flat, except for cutting a little low end from the amps pushing the 2x15 cabinets.

The bass legend joined forces with Hartke amps last year, and has been playing the Hartke Kilo ever since. The amp is featured on Black Sabbath’s new album, ’13.’ For more details on the Hartke Kilo, visit Hartke’s site.