The ?black sheep? of the 9-Series the Sonic Distortion offers the best characteristics of transistor and op-amp circuits in one compact unit. The SD9?s unique Low Boost/Hi Boost Tone control offers more low-end beef than other pedals while it?s Distortion and Output controls can provide up to 55 dB of gain boost. At low gain settings the SD9 functions perfectly as a full-frequency overdrive. Higher gain settings turn the SD9 into a hand-held monster; providing gut-wrenching grind and singing sustain that will make a clean amp dirty and a dirty amp downright evil.