Ampeg SVT-8 Pro Bass Head, preamp tube (2 x 12AX7, 1 x 12AU7), power amp: solid-state, 2500 watts @ 2 ohms, 1300 watts @ 4 ohms, 800 watts @ 8 ohms, tone controls: bass, mid, treble, mid tone control: 5-position, ultra low/high switch, balanced DI-out, effects loop, preamp out/power amp in, power amp emulation circuit, mute button, speakon out, dimensions whd: 19" x 3.5" x 14", weight: 23 pounds