"Eeyore" wrote in
message
Arny Krueger wrote:
"Eeyore" wrote
in
Arny Krueger wrote:
I notice that Self makes some heavy claims about a
proprietary implemention of class G.
I haven't heard that. I'd be curious to know how it can
be made proprietary !
http://www.dself.dsl.pipex.com/ampins/classg/g.htm
"Class-G is now out and about. So what has changed? This
would be easier to answer if there had been more
published on the technology; as it is I have to rely
pretty much on my own research. I found that Schottky
power diodes have eliminated the commutation-diode
glitching. Having peeled this skin from the distortion
onion, linearity was still signficantly poorer than a
Blameless Class-B design. This proved to be due to Early
effect in the output stage devices, stemming from the
sudden changes in collector voltage they experience in
Class-G operation. I had my own ideas about how to deal
with this, and you can read all in Electronics World for
Dec 2001 and Jan, Feb 2002. There is a fully worked-out
design, and even a PCB available to ease building it."
The "Early Effect" amounts to being an increase in beta
with increased VCE. The happens in a class-G amp when
the power supply voltage is switched to a higher voltage.
I notice that his ideas on the matter can only apparently
be read in the copies of EW mentioned.
His does pontificate a heck of alot !
I believe that Self also added some stuff on his allegedly new Class G
technology in his book.
"Audio Power Amplifier Design Handbook, Fourth Edition" It's about $50 in
paperback from Amazon.