Equinoxe: Voltage Controlled Phaser Module

Constructional Difficulty: Easy

This is our hugely popular version of the classic four stage OTA based phaser. Wonderfully lush and smooth, it is similar in sound to the phaser used by Jean Michel Jarre on the Oxygene and Equinoxe albums.

The unit includes a useful internal low frequency oscillator with accompanying bicolour LED. The centre frequency of the phase shifter can also be controlled by an external control voltage. Thus allowing envelope generators to be used to sweep the phaser to create filter type effects. Four front panel pots are provided:

Frequency: this controls the frequency of the two notches created by the phase shift network.

Emphasis: this accentuates the feedback signal within the phaser to create a deeper effect.

Modulation: A simple attenuator to adjust the level of the internal LFO or incoming CV.

LFO rate: adjusts the speed of the LFO.

The internal LFO produces a triangle wave output which is also available from a front panel socket, LFO OUT. This allows you to use the internal LFO for other modulation purposes. The LFO signal is automatically routed to the modulation depth pot when no jack is inserted in the CV IN socket. The module features an on board jumper to select whether the LFO OUT signal is inverted or non inverted compared to the modulating signal.

The unit is designed to work with standard MOTM/Oakley signal levels, although it could be easily converted to be driven from other sources including an electric guitar.

This unit is also available in small format (Euro size) as the RS400 Phaser from Analogue Systems.

For DIY builders of this module it is possible to purchase the Sock4 circuit board which is available separately. This little board speeds up the wiring of the four 1/4" sockets and reduces the chances of any wiring errors.

Power (+/-15V) is provided to the board either by our standard Oakley 4-way header or Synthesizers.com header. The board size is 143 mm (high) x 72mm (deep). Current draw is around 40mA.

An enhanced version of this module is also available featuring up to eight stage phasing. This is the Deep Equinoxe.

Sound Samples

Classic swirling chords similar to that heard on the Jean-Michel Jarre Album 'Equinoxe'. This particular sample was played on a Korg Polysix with standard string patch and ensemble mode on.

Single sawtooth wave from an Oakley VCO used as the raw input. The phaser is swept upwards manually by the Frequency pot. Emphasis is at 75%.

Three sawtooth VCOs feeding the phaser. The frequency is being swept on every note by an external EG triggered by the keyboard gate. Emphasis at zero. No other filters are used.

Three VCOs, one tuned an octave up. Again the phaser is being swept with an EG. This time the attack time is set to a medium amount so you can hear it sweeping upwards. Emphasis set to 100%.

Slightly filtered pink noise is fed into the phaser. Using the inbuilt LFO to modulate the frequency of the phaser. Emphasis at 100%. A little digital reverb has been added to the final output.

The Equinoxe issue 5 as a MOTM format module in a black finish Schaeffer panel. Note the use of the Sock4 socket board to help keep the wiring to the sockets neat and tidy.


Click here for how to order.

Equinoxe issue 5.1 PCB .................................. 16GBP

Sock 4 issue 2 PCB .......................................... 5GBP
Equinoxe pot bracket kit .............................. 0.75GBP

The optional Pot Bracket Kit contains the three 16mm Alpha pot brackets required to complete one module.

All other parts can be purchased from you usual electronic component supplier.

Shipping and postage is additional to these prices. See also the FAQ page.


User Manual

Builder's Guide

Construction Guide Our handy guide to building Oakley DIY projects

Parts Guide Our handy guide to buying parts for Oakley DIY projects.

Schematics are only available to purchasers of the PCB and will be sent via e-mail when the board(s) are shipped.

Front Panel database

A Schaeffer front panel can be made for this module. The database can be found by downloading the following link:

5U format in traditional black

To read these files you will need a copy of 'Frontplatten designer' from Schaeffer. The program also features on-line ordering, so its now even easier to buy your panels from Scheaffer.

The company are based in Berlin in Germany and will send out panels to anywhere in the world. Delivery to the UK normally takes around ten days. For North American users you can also order your Schaeffer panels from Front Panel Express.

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Copyright: Tony Allgood.
Last revised: February 29, 2024.