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Phaser

MXR Phase 90 Clone w/ "script" toggle mod - March 2020

BYOC Classic Phaser Icon

The Circuit

I based this circuit on the The BYOC Classic Phaser, which is a clone of the MXR Phase 90. The original Phase 90's are known for a slightly different tone than the modern ones, and I included a custom mod that allows me to toggle between the two modes by adding or removing the 22k resistor between IC3 and IC5.

At first this circuit did not work for me since I didn't match the characteristics of the JFETs. There is a lot of inconsistency in the manufacturing process of JFETs, and since a phaser requires all of the JFETs to respond identically, one must purchase extra JFETs and measure each one to find six that match.

This pedal is currently still on a breadboard awaiting a permanent enclosure.

BYOC Classic Phaser Boost Schematic

Components

Resistors:

  • 2 - 4k7
  • 10 - 10k
  • 5 - 22k
  • 1 - 56k
  • 6 - 150k
  • 2 - 470k
  • 1 - 1M
  • 1 - 3.9M

Capacitors:

  • 2 - .01uF film cap
  • 6 - .047uF film cap
  • 1 - 10uf Electrolytic
  • 1 - 15uf Electrolytic

Diodes:

  • 1 - 5.1v Zener diode

ICs:

  • 6 - DIP 8 socket
  • 6 - TL071 Single Opamp

Transistors

  • 4 - 2N5952
  • 1 - 2N3906

Potentiometers

  • 1 - C500k
  • 1 - 250k Trimpot

Hardware:

  • 1 - 125B Enclosure
  • 1 - 3pdt footswitch
  • 1 - LED
  • 1 – DC Jack
  • 2 – 1/4" mono jack