So what's the secret behind the PT999's timeless tone? Simple  the circuit used today is exactly the same as it was when first introduced in 1974. While many "reissue" effects on the market today are far from true to the original designs, Maxon has taken pains to keep the PT999 circuit unchanged for close to 30 years. The PT999's four-stage phasing circuit offers 720 degrees of phasing sweep variable from .2 to 14 Hz (cycles per second). The PT999's FET's (Toshiba #2SK246) are carefully sorted and matched by hand to produce the smoothest phasing sweep possible with low noise. Unlike other phasers, the PT999 runs negative feedback of the signal to each phase-shifting FET for less distortion. Internal trimmers adjust center frequency and width of the phasing sweep (calibrated prior to market, we recommend adjustment of these trimmers be left to a qualified electronic technician).

If you demand classic phase shifting effects without compromising your guitar's signature tone, the PT999 Phase Tone has no equals.