Warm Audio Mutation Phasor II Phaser Pedal

The Warm Audio Mutation Phasor II is an electro-optical phaser pedal that recreates a classic 1970s analog phase-shifting circuit. Built with a six-stage optical design using light-dependent resistors rather than FETs, it produces thicker, deeper phase shifting than standard four-stage phasers.

The Rate control adjusts sweep speed from 0.1 Hz (one sweep every ten seconds) to 18 Hz for fast, choppy modulation. The Depth control varies the width of the frequency sweep, from narrow, subtle movement to wide, dramatic sweeps across the full audio spectrum. The Feedback control routes part of the phase-shifted signal back into the input, emphasizing the notches and peaks of the phase sweep. At higher feedback settings, the "wooshes" become more pronounced and resonant, producing the kind of intense, underwater phasing associated with 1970s psychedelic recordings. The electro-optical design delivers smoother transitions than FET-based phasers because the light-dependent resistors respond with a natural, organic curve. The pedal works on guitar, bass, keyboards, and synthesizers.

Specifications

• Circuit: Electro-optical phase shifting, buffered bypass
• Phasing rate: 0.1 Hz to 18 Hz
• Controls: Rate, Depth, Feedback
• Components: RC4558P op-amps, vintage-style diodes, carbon resistors, film capacitors
• Frequency response: 20 Hz to 20 kHz
• S/N ratio: 86 dB (below 2V input)
• Power draw: 150 mA
• Power: 9V battery or 9V center-negative DC adapter (not included)
• I/O: 1/4" input and output
• Dimensions: 165 x 89 x 51 mm (6.5 x 3.5 x 2")
• Weight: 0.91 kg (2 lb)