When using a MRA amp in standalone mode you need to use a 24VDC power supply - the larger amp (24W) needs a 4 pin mini din plug which is painful as its not an off the shelf option for power supplies. When using the amps with the matrix switch you don't need a power supply - so that would mean that we can power the amps up via the digital Audio connection (RJ45) on the back - a sort of POE type setup. What are the specs for power on this connections and would it be feasible to power up the amps via the RJ45 plug when in stand alone mode? It may be simpler than trying to get a min din plug and guess the polarity