Maestro

PS-1A Phaser

MODULATION

PHASER

Description

The Maestro PS-1A Phase Shifter is a seminal six-stage analog phaser designed by Tom Oberheim in the early 1970s. Originally intended as a tabletop unit for keyboards, it quickly became a staple for guitarists seeking lush, rotary-speaker-style modulation. The circuit utilizes Field Effect Transistors (FETs) as tuning elements within cascaded all-pass filter networks to create its signature warm sweeps. A notable feature is the gradual ramping effect when switching between its three preset speeds—Slow, Medium, and Fast—mimicking the acceleration of a Leslie speaker. The unit’s simple interface consists of three colorful rocker switches borrowed from Lowrey organs, an affiliate company of Maestro's parent, CMI. It is renowned for its use by legendary artists such as Alex Lifeson of Rush and John Paul Jones of Led Zeppelin.

What's missing here?

We know that this pedal exists, but not much more.

You can change that by submitting improvements to this pedal! Don't worry, it's quick and easy with our Pedal Creator.

Technical data

Width

000.00 mm

Depth

000.00 mm

Height

000.00 mm

Weight

000.00 mm