AMPLIFIER HEAD FOR BASS 2x500w head, 1000w (bridged mono) at 4 Ohm, Class A preamp with 12AX7 tube, Equalization control: bass, middle and treble, Brightness selector, Limiter (led), Passive and active inputs, Balance ( A/B outputs), Balanced XLR direct output, 1/4'' Jack output, Effects loop, 2-unit rack format