The Control Modules

The circuit board for this project has now been discontinued. Ready made Control-3 modules are available from

These three modules are simple but very effective control modules. Each Control module is based around the same circuit board, the Four-pot PCB. This is then simply built up in one of the three ways to match your chosen panel option.

The Control-1 module in a standard 1U wide Oakley panel. This module features four independent voltage sources.

The Control-1 generates four very stable voltages. The output can be varied from -5V to +5V for each of the four outputs. Each output is completely separate and can control many modules without loosing accuracy. When the control knob is central, ie. pointing directly upwards, the output voltage is zero volts. You can use these voltages to control other modules within a modular synthesiser. For example, you can add offsets to CV inputs to increase the range of existing modules. This way you can drive your Oakley VCO to very low frequencies and use it as an LFO. Or you can deliberately cause audio inputs to go into asymmetrical distortion by forcing the input amplifiers into overdrive.

The Control-2 1U wide module. This features two voltage sources and one reversible attenuator.

The Control-2 generates two stable voltages in a similar fashion to the Control-1. However, this module also features a highly stable reversible attenuator too. In this section the control knob can be set so that the gain of the attenuators input is anything from -1 to +1. This means that the input signal, CV or audio, can be inverted and attenuated at the same time. You can make -4V into +4V and vice versa, or turn positive envelope outputs to negatively going ones.

The Control-3 2U wide module. This features four switchable voltage sources that can be used as reversible attenuators as well.

The Control-3 module is the big one. This uses a 2U wide panel to acheive multiple functions. You can use it as four separate voltage sources. Each section has a dedicated switch that can turn the output off and produce an accurate zero volts. Each section can be used as a reversible attenuator when the input jack socket has a jack plug inserted.

Remember that all three modules are made from the same 'Four pot' PCB. You simply build it up as your option dictates. On the board there are four identical reversible attenuators and one precision 5V reference.

Please note: the PCB has no additional mounting holes and is fitted to the front panel by Oakley pot brackets only.

Project Downloads

User Guide

Construction Guide Our handy guide to building Oakley DIY projects

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

Links to schematics are available to purchasers of the PCB or module 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 a 1U wide Control-1 and Control-2 modules, and the 2U wide Control-3 module.

The databases can be found here: control1.fpd, control2.fpd and control3.fpd. To read these files you will need a copy of 'Frontplatten designer' from Schaeffer. The program also features on-line ordering, so it's 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: October 06, 2011.