Powering Your Oakley Sound Modules

How do I power my Oakley Modular system?

I recommend that you build the Oakley Low Voltage power supply. It is safe, and relatively easy to build and set up. I do two types, one for 5U systems and one for Eurorack systems.

What are the other options?

You could buy a prebuilt power supply module from an electronic parts supplier or modular retailer. Some are obtained as open frame types. This is where the high and low voltage parts are accessible to misplaced fingers. Careful placement and assembly is essential for safe operation. Some are semi sealed units that have a metal cage around them to protect them and you. Choosing linear types over switch mode power supplies (switchers) should offer you lower noise and greater long term reliability. Some of the newer but more expensive switch mode supplies are very good but all of them will be electrically noisier than a good linear design.

For 5U there are many open frame linear types to chose from but the one I would recommend is the Bel Power Solutions HAA15-0.8AG. This supplies 800mA per 15V rail and is good for about 15 modules.

Wiring up these open frame supplies isn't quite as easy as one might think. So before you buy one make sure you know what you are doing - particularly regarding high voltage insulation and earth bonding. All power supplies give off heat when they are working and linear supplies generate lots more heat than switchers. Either type of power supply must be fitted so that they do not get too hot. Fitting your supply inside a sealed wooden box will inevitably lead to overheating.

Sorry, I will not enter into any discussions regarding building your own power supply or modifying an existing one.

Divide and conquer. Several smaller power supplies are often better than one big one.

Try to arrange your system so that each case of modules has its own power supply or power supplies. Try not to distribute power between cases as the long leads and additional connectors involved will introduce unwanted voltage drops and increase problems with module interference and stability.

A single 5A power supply may sound perfect for your large system but consider what happens if the power supply breaks down. Firstly, your whole system is down. But more importantly, if the power supply has failed in such a way so that it now allows the unregulated voltage from the transformer to reach your modules, this could damage all the modules in your system.

Furthermore, having one big power supply makes it more difficult (but not impossible) to distribute the power to all the modules.

The other problem with large power supplies is their ability to supply large currents into a fault. If there is a problem on a module and the power taken by that module becomes excessive, a smaller supply may well detect this and shut down or limit the current to a safe amount. A 5A supply will happily push 5A into a single faulty module and possibly cause more problems.

What are the Oakley Dizzy and MU Dizzy?

The Dizzy, MU Dizzy and Euro Dizzy are power supply distribution boards for the Oakley/MOTM, MU formats and Eurorack systems respectively. They do not generate power, but allow you to connect several Oakley/MOTM, MU, or Eurorack modules to one power supply. See the Dizzy, MU Dizzy, and Euro-Dizzy pages for more information.

Can I run 5U Oakley Modules from +/-12V rails?

All 5U Oakley modules are designed and optimised to run from +/-15V. However, some may run from +/-12V as they are. However, the great majority will need modifications, usually some resistor value changes, to run properly from the lower voltage (like the SuperLadder, ADSR/VCA). Some modules will not run on +/-12V at all (like the midiDAC).

Due to lack of time I am not able to answer any specific queries regarding the modification of 5U modules so that they can be powered from +/-12V rails. I would normally recommend that you purchase a +/-15V power supply. You will benefit from a larger headroom for all your signals too.

Can I run Eurorack Oakley Modules from +/-15V rails?

All Eurorack Oakley modules have been designed to run from +/-12V. Most will also run from +/-15V, although some will need some resistor values changing. Due to lack of time I am not able to answer any specific queries regarding the modification of Eurorack modules so that they can be powered from +/-15V rails.

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Copyright: Tony Allgood
Last revised: September 11, 2019.