This circuitry enables the player to achieve the dynamics and tone of a loud stadium-level amplifier at low to moderate volume levels. A second distinctive and crucial feature of the design is that an active mid-frequency preamp is positioned at the front of the FET distortion circuitry. This design characteristic provides the user with a wide sweep of tonal possibilities with any amp or guitar combination. This is the definitive pedal for adding the ultimate dirt channel to your amplifier. Simply engage the footswitch! It operates on 9V DC negative center power