The Keeley Psi Fuzz marries op-amp and germanium fuzz stages under one roof with controls for volume, tone and fuzz for an effect that traverses spectrums of fuzz from vintage smooth to sludgy attack. Based on the original IC Muff with personal appointments and attenuation by Robert Keeley himself, this pedal is just what the doctor ordered for those who want a vintage voicing in their fuzz with the option to press into more aggressive territory.