Clockworks PS 101 Instant Phaser

The Clockworks PS 101 Instant Phaser by Eventide is a vintage rack-mount effects unit that was in production from 1971 to 1977. It employed a series of eight FET-based analog all-pass filters to deliver lush phasing while preserving the original tone. The phaser introduced new concepts, including the use of the "Envelope" of the signal to drive the sweeping effect and the incorporation of two "decorrelated outputs."

The controls of the PS 101 Instant Phaser include:
- Function (Far Right Knob): Selects one of the four control types that modulate the phasing filters to create phase-shifted effects.
- Depth: Controls the mix of direct and phase-shifted signal.
- Oscillator: Controls the rate at which the low-frequency oscillator sweeps through the range of the phasing filters.
- Manual: Allows for full-range control of the phasing filters based on the knob's position.
- Envelope Follower: Tracks the input signal's amplitude to control the sweep of the phasing filters.

Additionally, the PS101 can be used to generate a "pseudo stereo" effect and simulate the Doppler Shift phenomenon. The Instant Phaser was priced at $575 in 1974, equivalent to more than $2,800 in today's dollars.

The PS 101 Instant Phaser was designed to eliminate the costly and tedious job of setting up and implementing the special effect known as "phasing" or "flanging." It was one of the first effects boxes used live and was known for its capacity to spread a mono image across the stereo field.