Although the RPSU can be used with an internal mains transformer, I recommend that builders use
an external low voltage output line lump or wallwart type mains adapter. This keeps all the high
voltages away from your project and ensures your safety. An example of such is the Yamaha PA-20
which is available from all larger music stores. Later on in this document I will give details on how
to build your RPSU module to suit your chosen method of supplying power.
The RPSU is 150mm by 51mm in size. It is a two layer board and made from double thickness
copper to reduce unwanted voltage drops along the copper traces on the board. Unlike the issue 1
RPSU board there are no trimmers to set the voltages to e/-15.00V. The SRE330 main
board's circuitry is not bothered whether the voltage is exactly 15.00V but only that it doesn't
change once the SRE330 main board has been calibrated. The RPSU board thus needs no trimmers
and produces a little over +/-15.3V when built as recommended.
The RPSU requires an AC supply of a minimum of 15V to work correctly. When used with a centre
tapped AC supply, such as that from the PA20 or internal mains transformer, the current taken is
approximately 0.4A (RMS). With a single phase supply, such as that from a standard AC output
wallwart supply, the current required will be in the order of 0.7A (RMS).
The three way power socket that will fit the Yamaha PA20 power supply.