Keeley set out to take a classic design with lots of history and make it obviously something new. To do this, they took the op-amp version of the old PI and inverted one of the stages, brought out the midrange, tightened the bass and, most importantly, added a Germanium transistor output! Yes, this is a op amp-transistor hybrid. Don’t be miffed by op-amps in your pie folks, the germanium touch at the end makes everyone smile around the shop here. The resulting Psi Fuzz provides thick sustain for creamy leads.