The solo uses three pairs of carefully matched (or should we say, carefully mismatched) clipping diodes to produce asymmetrical clipping. The three pairs are accessible via the “hot, melt, burn” slider switch. This has the effect of making the SOLO clip very much like a tube amp going into natural power-tube distortion.

Pro Co Sound also makes several other highly regarded effects including the popular RAT2, Turbo RAT, You Dirty RAT, and Deucetone. Each effect has its own unique tone structure.