Really ? Mosfet mist ? Weak in the bass department ?Don;’t know about the "mist" remark Mr D. But yes for the same given complimentary pairs of Mosfets v (BJT) Bi-Polar,(both with great power supplies) the BJT output stage amp will deliver much more current (doubling down to 2ohms) into low impedance’s than Mosfets can hope to. This is why you’ll see the reputation for best amps in the world that can drive evil loads that many of the great speakers have, are BJT amps. Cheers George |
George, as usual, you are talking about drive capability (specs ), into extreme low impedance loads. ( 1 ) I would never own a speaker such as that ( 2 ) There are many fine mosfet designs out there ( 3 ) You obviously feel tube amps are not very good, because they, too, cannot handle the extreme low impedance loads ( 4 ) jeffvegas is your new best friend ( 5 ) Amps using either bipolars or mosfets, can sound wonderful ( 6 ) Mosfets need to be driven differently than bipolars ( at least, this is my understanding ). Not every designer knows how to work with mosfets ( 7 ) Mosfet designs sound closer to tubes, which is a good thing, to many ( 8 ) As I said......to each his own....ymmv... .Enjoy ! MrD. |
Having been repairing Counterpoint hybrid power amps that used MOSFETS and converting them to bi-polar transistors, my experience finds the MOSFETS are very musical but do not measure up in dynamics, clarity and frequency extension compared to the same amps I rebuild with Mosfets. Same goes for the Class A amps I build. BUT it does come down t the design and implementation. Happy Listening. |
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Kudos bigkidz, my experience also, you need dynamics for reality, you need frequency extension for the full picture, this is where BJT’s shine. This is not just me, but there are many quotes on line from lecturers on the subject. here is just one " BJTs tend to have better, more linear gain characteristics…and can give you a lot higher voltage gain than MOSFETs.…They’re also able to handle higher output currents…and have a lower output impedance.…That gives BJTs a huge advantage over MOSFETs…for building amplifier circuits…that need to provide a significant amount of output power…and or drive loads that have low input impedance.…MOSFETs are going to have a harder time…driving a low impedance load…because they have a higher output impedance.…" Yes and before anyone says it, you can make Mosfets lower in output impedance, just put a **** load of feedback around them and they’ll equal a BJT then, but we all know too much feedback sounds like c**p. Cheers George |
