Hi, Vacuumlanders.
I just read this in IEEE Specturm magazine.
http://www.spectrum.ieee.org/feb08/5953
It's about a Belgium chap, Bruno Putzeys, who designs state-of-the art
Class-D amplifiers - that's solid state switchers for the uninitiated.
I have long recognized that a solid state unit can be a better "short,
thick wire with gain" delivering "any" current at "any" voltage at
"any" frequency into "any" speaker load at "zero" distortion (OK, some
hyperbolae here!) than a tube amplifier. However, I've always felt
that the epitome of the solid-state power stage was the big linear P-P
MOSFET. Thus, I've never liked Class-D audio. But I may have to revise
my prejudices!
There are two short reference to tube audio in the article. One
states that the Bruno's latest Class-D amplfier has "30,000 times less
distortion than some (sic) tube amplifiers". OK, that "some" hides a
lot... An 50C5 O/P stage in an "AA5" AC/DC radio receiver may have
10% THD at at 2 watts (or less)... Unfair reference, any decent tube
amp can beat 0.1% easily. Hmmm, I'd settle for 30,000 times less than
10%, or 0.00033% THD. Indeed, the figure given is 0.0003% at 20 KHz
at "full power" - the latter not defined but presumable at least 20
watts/ch, likely more.
So, read and enjoy. I'll stick to tubes for the fun, the "hands-
on" (anything can be fixed), the rosy glow and the overall vintage
aura. Oh, and for serious listening? (That's classical piano for me.)
A 40 lb, over 100 wpc linear S/S stereo unit and a pair of Ditton
442's... don't shoot! <g>
Cheers,
Roger
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