Class A Solid State Sound

George might not be right all the time, but he’s never wrong.

Thank you, and if so in other posts I’ve always admitted when I was wrong, and always started with the word "sorry".
https://thumbs.dreamstime.com/z/delicious-cartoon-character-sign-isolated-white-background-vector-il...

"To say it once again for the last time, complementary pair for complementary pair, you’ll get more amperage (current) from a BJT (bi-Polar) output stage than you will a mosfet output stage, end of story."

This is why all the amps out there that are "known" to drive huge current into sub 2ohm loads, like the Wilson Alexia S1 0.9ohm, and keep almost doubling their wattage down to that, are all BJT’s (bi-polars) output stage poweramps.

Cheers George

How about PS Audio's BHK  Signature 300 with a tubed input stage and MOSFET output stage using exclusively n-channel devices for both the positive and negative signals.  Claimed power output is 300/600/1000 wpc into 8/4/2 ohms and according to JA's measurements those specs are mostly confirmed with 370/620/950W into 8/4/2 ohms, although like many manufacturers, it appears they sort of fudge the 8 ohm power rating (lower than actual) so they can claim that the amp " doubles the output current with half the impedance."

I appreciate that they provide a power rating at 2 ohms but cannot help wondering the reasons for JA's comment that the amp "was less comfortable at lower powers into this low an impedance" (i.e., a 2 ohm load), and Fremer's comment that, "there's still more weight, power, and physicality to be had in the very lowest octaves."  Curious why an amplifier that provides 950 wpc into 2 ohms would be anything less than a powerhouse into low octaves.  Does the MOSFET output stage have something to do with it or, how about the dual differential design?

output stage using exclusively n-channel devices for both the positive and negative signals

This topology may not have low enough output impedance vs. push-pull complementary N/P pair.  And output impedance is freq. dependent so may be that could explain its performance at 2ohm.

JA - "The output impedance (including the series resistance of 10' of speaker cable) was on the high side for a solid-state amplifier, at 0.16 ohm at all audio frequencies."