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on the current draw – the more outputs that are connected to inputs increases the current
draw slightly. It may also increase when any LEDs light up.
An M4 ring terminal crimped to 24/0.2 insulated wire. This sort of connector is suitable for connecting to
the output terminals of the PSU2.
I recommend that you use a Yamaha PA-20 or PA-30 power supply. These are neat tidy
external power supplies that keep the dangerous mains voltage away from your modular. The
PA-20 will allow a maximum current of 520mA (0.52A) to be drawn from each rail. While the
PA-30 will allow up to 780mA (0.78A). Both the PA-20 and PA-30 are centre tapped AC
supplies with three wires within their output cable and use a three pole connector.
Other power supplies are available and they come in lots of different variations. Other than AC
output voltage the two key specifications are output current (please don't call it 'ampage'), and
whether the output is centre tapped or single phase. In almost all cases the outputs of standard
AC output power supplies are single phase. You can tell because they only have a cable with
two wires inside which terminates in a two pole connector.
A single phase AC output supply will allow only slightly more than a quarter of its rated
current output. For example if you are using a 500mA (or 0.5A) AC wallwart* then the most
current you can take from this power supply module is around 125mA from each rail. That is,
take no more than 125mA from either the +15V supply and 125mA from the -15V supply.
Various companies make linelumps** with a greater capacity than 500mA. If you can get a
single phase 1A output one than this will be able to drive up to 250mA per rail.
The Oakley PSU2 can be used with full wave or half wave rectification. The former allows it
to utilise split AC outputs. With full rectification and using a centre tapped power supply the
amount of current taken from each 15V rail can be up to just over half the rated current
output of the power supply. The Yamaha PA-20 supply is rated to give an output voltage of
35Vac (with a centre tap) at a load of 0.94A. Once rectified and smoothed this means that a
maximum current of 0.52A can be drawn from each rail.
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