Deep Equinoxe: Voltage Controlled Eight Stage Phaser Module

Constructional Difficulty: Moderate

This is an upgrade of our four stage OTA based phaser design, the Oakley Equinoxe. The original was wonderfully lush and smooth and similar in sound to the phaser used by Jean Michel Jarre on the Oxygene and Equinoxe albums. The Deep Equinoxe goes further. An additional two or four stages can be added deepening the effect creating a very rich and animated sound.

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 and two switches control the module:

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

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

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

LFO rate: This pot adjusts the speed of the LFO.

Norm/Deep: This two way toggle switch selects between the classic four stage Oakley Equinoxe mode and the Deep modes.

Six/Eight: This two way toggle switch selects between six stage or eight stage phasing when in Deep mode.

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.

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.

The Deep Equinoxe uses a standard Equinoxe PCB (issue 5 or above) with the Deep Equinoxe daughter board installed neatly above it. A simple six way interconnect joins the two boards together. Please note that the Deep Equinoxe board cannot be easily retrofitted to older Equinoxe boards.

Power (+/-15V) is provided to the board either by our standard Oakley 4-way header or header. Current consumption is approximately 45mA per rail.

The board size is 143 mm (high) x 72mm (deep).

Sound Samples

Bass drone firstly in NORM (4 stage), SIX and then EIGHT. Modulated by internal LFO set to a slowish speed.

Bass drone firstly in NORM (4 stage), SIX and then EIGHT. Modulated by the internal LFO set to a faster speed.

Simple riff firstly in NORM (4 stage), SIX and then EIGHT. Modulated by an external envelope which sweeps the frequency.

Simple sequence with triplet delay using the internal LFO to modulate the phaser's centre frequency.

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.The Deep Equinoxe is set to NORM mode.

The Deep Equinoxe as a MOTM format module in a natural finish Schaeffer panel. The Deep Equinoxe board fits on top of an issue 5 Equinoxe PCB. Note also the use of the Sock4 socket board to help keep the wiring to the sockets neat and tidy.


Click here for how to order.

Deep Equinoxe Daughter PCB issue 1 ......... 12GBP
Equinoxe issue 5 PCB ..................................... 19GBP

Both of the above PCBs are required to complete one Deep Equinoxe module.

Sock 4 issue 2 PCB ........................................ 5GBP
Equinoxe pot bracket kit .................................. 0.75GBP
J201 J-FET ....................................................... 3.50GBP

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.

All prices include VAT at UK rates. Shipping and postage is additional to these prices. See also the FAQ page.

Equinoxe ready made modules will be available from


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.

Use 'save as...' button to download and view the files. IE users need to right hand mouse click and then choose 'save as'.

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

5U format in natural finish

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.

A closer view of the Deep Equinoxe daughter board. The two boards are joined by a six way flexible interconnect - you can see the top part of the connection labelled 'DEEP'. I have used the LM13600 dual OTA in this particular unit but you can also use the more common LM13700 too.

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Copyright: Tony Allgood.
Last revised: September 01, 2018.