SQ differences between different amps

LittleCar_w/12s

Well.. as for why to use Mosfets:
-- They are MUCH more stable at higher temps
-- They don't draw as much power (talking about wasted power draw here, not power for the speakers)
-- Run cooler
As for BJTs:
-- Much more frequency stable at higher amplifying factors
-- Draw lots of power that is wasted to make them Temp stable (referred to as degenerative feedback)
-- They inherently run hotter because of this /\

-Jerry

LittleCar_w/12s

I have a ? for BKNauss:
Why do manf. always boast a Mosfet power supply? I have had no problems with h-bridges made of BJT's. They just hate silicon??
-Jerry

neomagus00

okay, that helps a lot too. i didn't understand the decade bit, but i get it now. why does it begin to shift phase before the xover point? or, if there's no simple answer, you can throw up a couple of those links and i can see how i do w/ them, then maybe you can try again to educate my dum bass . even if i don't get all of it, they should help somewhat - at least so i know what an h-bridge is, etc.

jerry - if most manufacturers use mosfets, who uses bjt's? they sound like a better product (at least from what you've said, and for my application), so i may be interested in getting an amp that uses them.

exalted512

Originally posted by LittleCar_w/12s

Why do manf. always boast a Mosfet power supply?

for the same reason they boast peak ratings
-Cody

LittleCar_w/12s

Man, that was a due answer... sorry I asked
-Jerry

AustinKP

Are there any good amps that use BJT's instead of MOSFETS? If so, are they worth the money?

neomagus00

hey, i was searching for an old post, and if anyone has an answer to the last post of this thread, can they throw it up here?

LittleCar_w/12s

Older lines of amps, I think it's typical for newer amps to use mosfets because of the design cost of producing a degenerative feedback circuit for standard transistors. The standard transistors have to be balanced to not distort from heat caused by peaks in output. The mosfets tend to be unable to handle the power of transistors, so what we get today is half mosfet, half transistors, it's really hard to say, and you can probably bet on both being in there.
Timeline would be... tubes, germanium transistors, silicon transistors, then mosfets... it's really hard to say what's better, and like I said, most use both technologies inside.