[DecibleDude]

I've been under the impression for a while that MOS FETs run cooler than other output devices. It occurred to me that I'm probably missing something because I remember that a MOS FET Hafler amp I once had used huge heat sinks and was only about 100 wpc. By comparison some other MOS FET amps have relatively small heat sinks. Can someone explain this seeming dichotomy to me.

Thanks

[FullRangeMan]

I've been under the impression for a while that MOS FETs run cooler than other output devices. It occurred to me that I'm probably missing something because I remember that a MOS FET Hafler amp I once had used huge heat sinks and was only about 100 wpc. By comparison some other MOS FET amps have relatively small heat sinks. Can someone explain this seeming dichotomy to me.

Thanks

It depend on some factors>
Bias load used in the circuit
Max load values recommended
Max temperature value allowed
Room temperature etc
There are new Transistors releases everyday, they are always evolving.

[DecibleDude]

Thanks FullRangeMan.