The DOD Overdrive Preamp/250 is an officially license e-pedal. This high-gain preamp has been a classic for nearly four decades. It can be used to produce a natural distortion, or overdrive the input of a guitar amplifier to increase the amp's natural sustain at any desired volume. At a lower gain setting the Overdrive Preamp 250 can be used to produce soft "tube type distortion." By increasing the amount of gain, extreme distortion rich in odd numbered harmonics can be produced creating a full rich sound.