I am currently trying to get a 4 amps output with 28 volts from a wall-mount rectifier(RW748U) that has ajustable current of 0-12 amps, and voltage without load of 54 volts and 48 volts with load. This rectifier has a power rating of 700W. I have burnt resistors trying to connect in parallel and then in series. This is a urgent project requirement that is due next week. The power out of this rectifier has to give power to the power amplifier that we are trying to build. Can a circuit diagram be given of the best calculatons of the resistance to use and what about the power ratin of the resistors? What sort of load can I test the power supply with? As far as the manual of this rectifier is saying, the current is adjustable therefore it means that it will only chew up the current required for the load.