Could someone please explain how a MOSFET quasi complementary output stage (all N-channel FETS) really works? Kind like the one off www.aussieamplifiers.com
Are the high-side FETs operating as source followers (for the postive side) while the low-side FETS acting like transconductance amps (for the negative side)? Please help!
Are the high-side FETs operating as source followers (for the postive side) while the low-side FETS acting like transconductance amps (for the negative side)? Please help!
N-channels rule!
Look in any catalogue and you will find seriously big N-channel Hexfets and IGBT's. Big enough to need bolts to attach the conductors. In contrast, P-channel devices wimp out comparitively early on the buahahaha scale. Super duper sized amplifiers (not necessarily audio) may well need to use a pair of N-channel devices for this reason.
GP.
Look in any catalogue and you will find seriously big N-channel Hexfets and IGBT's. Big enough to need bolts to attach the conductors. In contrast, P-channel devices wimp out comparitively early on the buahahaha scale. Super duper sized amplifiers (not necessarily audio) may well need to use a pair of N-channel devices for this reason.
GP.
If you need an example of a quasi-comp Mosfet output
stage, you can check out the 60 watt Mosfet upgrade on
an HK Citation 12 at www.passdiy.com
Sounds tho, like D. Self doesn't like quasi-comp Mosfets
stage, you can check out the 60 watt Mosfet upgrade on
an HK Citation 12 at www.passdiy.com
Sounds tho, like D. Self doesn't like quasi-comp Mosfets
I like to be agnostic about it, and I've made plenty of
money with both.
Bipolar are great if you are trying to get decent distortion
with a low bias AB amp. Home theater stuff is a good example.
Mosfets are the choice if you have high voltages and power,
or if you want simple Class A circuits. In general, they tend
to be easier to design with if you can afford lots of bias.
money with both.
Bipolar are great if you are trying to get decent distortion
with a low bias AB amp. Home theater stuff is a good example.
Mosfets are the choice if you have high voltages and power,
or if you want simple Class A circuits. In general, they tend
to be easier to design with if you can afford lots of bias.
Kilowatt said:And Slone loves them.
Slone does state MOSFETs will have more distortion than bi-polar. Self is just a bit more retentive about distortion than Slone.
Phil
Nelson Pass said:Properly designed, the Mosfets are a lot more rugged
since they don't have second breakdown at high
voltages. Your typical 250 watt Bipolar becomes a
wimpy 50 watt device at 150 volts. Not so with the
Mosfet.
MOSFET amps lose about 7 volts across the bias stage so unless you use a slightly higher voltage rail for the driver stage you lose a bit of power.
I designed a 450WRMS MOSFET power amp it has been very reliable for disco and guitar work.
I do tend to overdesign my amps with huge heatsinks and a pair of fans to keep it cool. It just never even gets warm.
I did find care has to be taken setting up the bias level and output DC offset voltage.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Solid State
- MOSFET Quasi Complimentary ???