1973 and 1975 was a significant phase for pedal effects as numerous phase shifters ideal for gigging guitarists emerged on the market. A handful of great-sounding but bulky units were introduced previously, like the Uni-Vibe and Maestro PS-1A, but this era saw the introduction of numerous guitar-friendly devices that included the Electro-Harmonix Small Stone, the Maestro MPS-2 Mini-Phase and its identical counterpart the Oberheim P-100 Phasor, the dazzling, sophisticated Mu-Tron
