Mosfet mist?


Greetings,

I have read several articles on the sonics of mosfet amps to include Adcom,B&K,Counterpoint,Perreaux,etc. What exactly is mosfet mist and how would one know what to listen for. Are some amps more prone to this mist than others? I have a Perreaux 1150B doing woofer duty on a pair of Focal 706s spkrs(A modified Parasound 1000A on top)How would say the 1150B compare with a B&K in relation. Thanks.
south43
By the way Adcom especially the older ones, like the 555 used Bipolar transistors and they sucked. They were suppose to be the poor mans Krell, no way.
The 'MOSFET mist' is a term coined that points to the problems of driving extremely capacitive inputs of the output devices of a MOSFET-based amplifier. If the driver circuitry lacks the current to deal with this capacitance, there will be a high frequency roll-off, hence the term.
Very well said Atmasphere,that is exactly what happens and I have heard it on speakers with a lot of capacitance in their crossover networks like 18/24db designs and large caps in thier woofers,shunts for instance.Mosfet amps tend to sound quite nice with 6db network speakers.Now back to my collected Mosfet Mist.Anybody out there want any free samples?
Would you rather be bipolar or have a mosfet mist? The choices are unsettling.
Atmasphere is the capacitance of the MOSFET that you describe is it of the non linear kind i.e. does it bounce around at different frequency and amplitudes?