I have a power supply a Kenwood PS-30. It usesd two 2n5885 transistors. I have seen other power supplies use 2n3772 transistors. In any case I would like to use power mosfets instead of bipolar transistors if it would be better. I know the mosfet wont be turned on all the way so cant take advantage of the low ohms there, so I guess my question is: Will a mosfet be better than a bipolar, running cooler and dissipating less heat? If so what kind of modification would I need to make? I am thinking of adding a resistor from the gate to ground and adjusting the gate voltage accordingly to obtain the proper output. But I could be way off here. What is your take on this? How can I use a mosfet as a pass transistor in a power supply or is it a bad idea?