Maestro PS-1A Phase Shifter — legendary early ‘70s analog phaser designed by Tom Oberheim for Maestro/Gibson. Features the unique 3-speed rocker switch system with smooth Leslie-style ramping between speeds, delivering deep, lush vintage modulation. Famous for classic rock, prog and keyboard tones. Rare and highly collectible USA-made effect. *SOLD AS IS - Needs service / calibration - only about half the stages seem to be present in the cycle - very asymetrical*