ClassA, how does it work?

lumanauw · 10th March 2008, 06:40 AM

http://www.google.com/patents?id=tUu...udio+amplifier

How does it work? Why the example use only +/-14V, and the selfoscilating frequency only 100khz?

Won't work for +/-50V at 400khz?

TheMG · 10th March 2008, 12:49 PM

All it is is a Class D amplifier driving a Class A amplifier output stage. Doesn't make any practical sense, since you're losing nearly all the benefits of the high efficiency of Class D and end up with a VERY inefficient amplifier.

fredos · 10th March 2008, 01:37 PM

I think that MG didnt read carefully...The class d just lift the low voltage psu of the class a amplifier to provide high voltage output swing. Since it lift the power supply form the middle point, no power supply perturbation will affect the class A stage. Funny that this is very close to the labgruppen patent...

Pafi · 10th March 2008, 03:56 PM

I'm almost sure I have seen the first figure (I mean: an equivalent schematic) earlier than 2006. I don't think this is an invention. It's sooo trivial!

Ouroboros · 10th March 2008, 04:39 PM

Peter Walker back in the 1970s spoke about the possibility of a Quad405-like current dumping arcitecture but using a class-D amp as the beefy 'current dumping' source.

Tim__x · 10th March 2008, 08:33 PM

Current dumping is a different concept.
This is class-H/tracking supplies, it's not all that unique, it's not new, and it's not that great of an idea.

lumanauw · 11th March 2008, 10:33 AM

I can only guess, this schottky+1000uF is a clever way to make use of the residual of IRAUDAMP system. IRAUDAMP use pre-filter feedback point.
Fredos, I think it is a bit different than labgruppen patent, since the sources of final mosfets are only connected to schottky+cap bank floating supply. I also don't know how can we adjust the margin (VDS) of this scheme. Maybe adjusting the cap value?

10th March 2008, 06:40 AM	#1
lumanauw diyAudio Moderator Emeritus Join Date: Oct 2002 Location: Bandung	ClassA, how does it work? http://www.google.com/patents?id=tUu...udio+amplifier How does it work? Why the example use only +/-14V, and the selfoscilating frequency only 100khz? Won't work for +/-50V at 400khz?

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10th March 2008, 12:49 PM	#2
TheMG diyAudio Member Join Date: Jan 2008	All it is is a Class D amplifier driving a Class A amplifier output stage. Doesn't make any practical sense, since you're losing nearly all the benefits of the high efficiency of Class D and end up with a VERY inefficient amplifier.

10th March 2008, 01:37 PM	#3
fredos diyAudio Member Join Date: Mar 2005 Location: Quebec	I think that MG didnt read carefully...The class d just lift the low voltage psu of the class a amplifier to provide high voltage output swing. Since it lift the power supply form the middle point, no power supply perturbation will affect the class A stage. Funny that this is very close to the labgruppen patent...

10th March 2008, 03:56 PM	#4
Pafi diyAudio Member Join Date: May 2004 Location: Budapest	I'm almost sure I have seen the first figure (I mean: an equivalent schematic) earlier than 2006. I don't think this is an invention. It's sooo trivial!

10th March 2008, 04:39 PM	#5
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	Peter Walker back in the 1970s spoke about the possibility of a Quad405-like current dumping arcitecture but using a class-D amp as the beefy 'current dumping' source.

10th March 2008, 08:33 PM	#6
Tim__x diyAudio Member Join Date: Jun 2004 Location: Edmonton area, Alberta	Current dumping is a different concept. This is class-H/tracking supplies, it's not all that unique, it's not new, and it's not that great of an idea.

11th March 2008, 10:33 AM	#7
lumanauw diyAudio Moderator Emeritus Join Date: Oct 2002 Location: Bandung	I can only guess, this schottky+1000uF is a clever way to make use of the residual of IRAUDAMP system. IRAUDAMP use pre-filter feedback point. Fredos, I think it is a bit different than labgruppen patent, since the sources of final mosfets are only connected to schottky+cap bank floating supply. I also don't know how can we adjust the margin (VDS) of this scheme. Maybe adjusting the cap value?