The schematic for the First Watt F5 shows an IRFP 240 and IFRP 9240 in the output stage.
However, continous Id = 12 Amps for the IRFP 9240 p channel MOSFET.
Other DIY'ers have suggested Toshiba 2sk1530 / 2sj201 or 2sk3497 / 2sj618 partnerings.
However, these are also limited to 10 or 12 Amps.
Vgs(off) is between 2v to 4v for all of these Mosfets.
Gamut Amplifiers also use a single Mosfet pair per channel, but have much higher power ratings.
Also, what I consider to be important - very low output Impedance.
Years ago I designed a 1 hp DC motor speed controller with a FB180SA10 Mosfet.
This beast can handle 120 Amps @ 100 oC with a channel resistance of 0.0065 Ohms.
One possible p Channel Mate is a IXTN90P20P, rated at a meager 90 Amps @ 25 oC.
Both these MosFets also have a Vgs(off) between 2v and 4v.
The problem is they are about $35 each.
Does any one have any other suggestions for high current Mosfet's for a First Watt F5 ?
However, continous Id = 12 Amps for the IRFP 9240 p channel MOSFET.
Other DIY'ers have suggested Toshiba 2sk1530 / 2sj201 or 2sk3497 / 2sj618 partnerings.
However, these are also limited to 10 or 12 Amps.
Vgs(off) is between 2v to 4v for all of these Mosfets.
Gamut Amplifiers also use a single Mosfet pair per channel, but have much higher power ratings.
Also, what I consider to be important - very low output Impedance.
Years ago I designed a 1 hp DC motor speed controller with a FB180SA10 Mosfet.
This beast can handle 120 Amps @ 100 oC with a channel resistance of 0.0065 Ohms.
One possible p Channel Mate is a IXTN90P20P, rated at a meager 90 Amps @ 25 oC.
Both these MosFets also have a Vgs(off) between 2v and 4v.
The problem is they are about $35 each.
Does any one have any other suggestions for high current Mosfet's for a First Watt F5 ?