The Big D is an extremely versatile distortion pedal capable of many different sounding ranging from a light bluesy ovedrive to modified hi-gain tube amp distortion. The Gain control varies the amount of overdrive. The Level varies the output. it sounds best if set a bit louder then with the pedal turned off and the Tone control the amount of bass response for a really BIG growling tone! 5-way Diode Select: Left to right, 1. Classic overdrive, tight and controlled 2. More output and gain then #1 3. Still more output and gain, increase bass response 4. More output then #3, less clipping, a more open sound 5. Less overall output verging on fuzz with slight compression. It also ahs a clip that changes the dynamics of the clipping. Hard: Increases output, less clipping Soft: Less output, more clipping.A lot of control over the type of overdrive - this pedal can do all your distortion pedal jobs from blues to hard rock, to metal on up to vintage fuzz, and modern industrial type tones.