Deep Equinoxe: Voltage Controlled Eight Stage Phaser Module

PCBs for this module are now discontinued

There are two suggested front panel designs. The one on the left is the original two switch variant, while the one on the right uses a single three position switch.

This is an upgrade of our four stage OTA based phaser design, the Oakley Equinoxe. The original Equinoxe is a wonderfully lush and smooth effect and similar in sound to the phaser used by Jean Michel Jarre on the Oxygene and Equinoxe albums. But the Deep Equinoxe goes further. An additional pair of double stages are added, to give a total of six and eight stages respectively, 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 'two position' switches or one 'three position' switch, 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.

The number of stages used is determined either by two 'two position' switches as my original design, or by the newer design that uses a single three position switch. For the two switch option the two switches are as follows:

Normal/Deep: The top toggle switch selects between the classic four stage Oakley Equinoxe mode and the Deep modes.

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

For the newer single switch design, the switch simply selects between four, six or eight stage modes directly. The single switch is more intuitive to use, but uses a less common switch and is slightly more complex to wire up.

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 0.1" 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. Maximum current consumption is approximately 50mA per rail.

The main board size is 143mm (high) x 72mm (deep) and the Deep Equinoxe daughter board is 77mm (high) x 65mm (wide).

The two switch version of the Deep Equinoxe module in the MOTM format with 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.

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 module built with the single switch option. The special 1P3T switch selects between four, six and eight stage modes.


Builder's Guide

User Manual

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 (two switch version) in traditional black

5U format (two switch version) in natural finish

5U format (one switch version) in traditional black

5U format (one switch version) 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.

The Equinoxe main board connects to the Sock4 socket board with an eight way 0.1" Molex KK interconnection. The Deep Equinoxe connects to the main board via a six way 0.1" header and socket system.

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Copyright: Tony Allgood.
Last revised: March 25, 2024.