Boss DS-1
Guitar pedal Boss Distortion DS-1 is equipped with three knobs: tone (Tone), Distortion (Dist) and volume (Level).
With Level You can adjust the output level, and Dist controls the degree of distortion. In the middle position, which is fixed by a click, the sound has a uniform proportion of the top and bottom. The optimum position of the knob colors - just left of the middle, as a DS-1 provides and so many top.
All the benefits of a DS-1 pedal appreciated Steve Vai and Joe Satriani, because it is when you play lead guitar it reveals its the best.