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 systemsand 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-Dizzypages 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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