While creating SS-11 we were guided by the motto - minimum size with maximum functionality for full tube overdrive with the highest quality components. The SS-11 is brother to the SS-20, but designed to be different. While the SS-20 is the more aggressive "METAL" pedal, the SS-11 was intended and manufactured for that famous CLASSIC tube driven over saturated guitar tone that eveyone loves and craves. The SS-11A Classic version is designed to cover all the classic jazzy, overdrive, and rock sounds of vintage tube amplifiers. The gain circuitry of LEAD channel is slightly less aggressive than the SS-11B (Clean and Crunch are the same). However, don't misjudge the A unit. It has plenty of bite and dirt, as seen in the demo videos. The SS-11A is a perfect choice for the guitarist who wants to cover everything!