The infamous Monolith Magma! A gnarly Sunn Beta Lead clone preamp. This one has been completely gone through. Wiring cleaned up, connections resoldered, all new op-amp chips & power transformer. This is a fire breathing monster! The drive aside, the clean tones are great. I've gotten a very good Geezer Butler type tone out of it. Just dropped $300 in parts & labor, fresh from the tech!