The issue 2.1 Oakley EPSU built with the
linear option that uses a more traditional 78M05 to create the +5V
rail. Note also the 0V bonding point and 0V connection to a ‘grounding’
4mm banana plug.
The Oakley EPSU is a triple output (+12V, -12V
and +5V) power supply design that is perfectly suited to powering
a small to medium sized eurorack modular. Final output current
capability is dependant on AC power source, the choice of
smoothing capacitors and the heatsink used. However, with a
suitable heatsink, capacitors and power source the Oakley Euro
PSU has been tested successfully at up to 1A (+/-12V) and 250mA
(+5V).
The PSU module must be fitted to a suitably
large metal panel to act as a heatsink for the two or three power
devices.
It is designed to work with our Euro Dizzy power distribution board. Up to four Euro Dizzy
boards may be connected directly to the PCB via the faston
connectors fitted to the board. Other makes of distribution board
can of course be used.
For safety reasons it is expected that the
unit will be used with a external centre-tapped linelump (mains
adapter) like the Yamaha PA-20 or PA-30. The PA-20 will allow the
PSU module to provide up to 520mA per 12V rail, while the PA-30
will supply up 780mA per 12V rail. The +5V rail can be created
with either a standard linear 78M05 regulator or equivalent
switch mode convertor.
Greater current outputs can be
supported when used with an appropriate transformer or line lump.
The board will support mains transformers with either twin or
tapped secondaries.
A component level
mains transformer should only be used if you know how to connect
high voltage wiring. On no account should this project be powered
by a component level mains transformer if you are not familiar
with fusing, earthing and safe connection of high voltage
equipment. For safety reasons Oakley Sound can only endorse using
this module with a low voltage input, such as the Yamaha PA-20 or
PA-30.
The two main power devices must be fitted
to a suitable heatsink to allow heat to be safely taken away.
This is the ‘switch mode’ option which uses a DC-DC convertor for
the +5V rail.
The power supply uses standard
parts throughout and requires only a simple voltmeter to set up.
The circuit board takes less than an hour to build.
Various options are available
for different types of switching, earthing and power on
indication. The strong glass fibre PCB is silkscreened for easy
component identification. It uses generous pad sizes, through
plated holes for easy soldering and wide 2oz copper double sided
tracks for reliable operation. The PCB is 5.95″ (151mm) x 3″
(76mm) in size.
Project Downloads
Euro PSU issue 2 Builder’s Guide
Euro
PSU issue 1 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.
An earlier version of the Oakley Euro PSU
driving three Euro Dizzy boards on a rear mounted 4U high 19″
rack panel.
The three pin power socket for use with
external PA-20 and PA-30 power supplies.
A direct mains powered EPSU driving four
Euro Dizzy boards.
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