Until Fulltone"s OCD (Obsessive Compulsive Drive), pedals just couldn"t hold up to what a high quality amp could do. You lose all the touch sensitivity, and you can forget about those complex Harmonics. It"s always been somewhat of a compromise using Overdrive pedals until now. The Fulltone OCD is designed to replicate the dynamics and harmonic structure of an overdriven tube amp, it uses a unique multi-stage distortion circuit, as opposed to the more common diodes-in-feedback-loop/diodes-to-ground configurations. The designers at Fulltone made the OCD for themselves, but they"ll let you use it too. And you"ll love it!