The recommended option: The Yamaha PA-20
This is a linelump supply and features a fixed 17.5-0-17.5 volt AC output at 0.94A maximum. This
means it gives us two AC outputs with a centre tap or mid point reference voltage. So unlike a more
common single phase AC adapter output with two leads, this one has three. This means you need to
use the Oakley RPSU in full wave rectification mode. That is, both fuses must be fitted and all four
of the big rectifier diodes.
The PA-20 is made for Yamaha products and they are available from Yamaha spares departments
as well as many music shops, eg. Thomann. These are CE approved and connect to the mains via
your local mains connector. They will be different types depending on the country you need them
for. It comes with a handy three way plug at the low voltage end that you can use with an
appropriate socket. If you wish you can ditch their connector and use your own.
In the UK the line lump’s part number is V9812300 and the is around £35. If you are buying these
direct from Yamaha and, for some reason, are asked why, the probably best thing to say it is for a
MG12/4 mixer.
Once rectified, smoothed and regulated the Yamaha PA-20 can deliver up to 0.52A continuously
into both 15V rails.
You should fit both fuses and both should be anti-surge types and rated at 800mA, often written as
800mAT on the fuse body.
The European version of the PA-20. Other country's units are similar but will have the local mains connector
fitted.