N.Sano, T.Hayashi, H.Ogawa,"A high-efficiency class-A audio amplifier", AES preprint

[jez]

N.Sano, T.Hayashi, H.Ogawa,"A high-efficiency class-A audio amplifier", AES preprint

I have not been able to find a copy of the article in the title of the thread so..... Could anyone P.M. with a copy?
It was the basis for the Technics SE-A1 hand built high end class A amp from around 1978. A certain Mr. N. Pass described the article as "a masterpiece" and was inspired by it to patent one of his own creations.....
Thanks in advance,
Jez.

 

[smartx21]

N. Pass must be Nelson Pass.

 

[Danish]

AES E-Library: High Efficiency Class A Audio Power Amplifier (Class A+ Amplifier)

 

[tiefbassuebertr]

check out this pdf files:
http://www.diyaudio.com/forums/solid-state/23590-audiotek-69-technics-se-a1.html
http://www.bgaudioclub.org/uploads/docs/High_Performance_Audio_Power_Amplifiers,_B.Duncan.pdf
http://www.bgaudioclub.org/uploads/docs/Self_on_Audio_Second_Edition.pdf

 

[jez]

Thanks guys but already have all the references mentioned by Tief.......
It's just an idle technical curiosity to me rather than anything commercial and I'm not curious enough to part with $20 to get it from the AES!

 

[StevenOH]

This topology is useful for high power amps. Technics US pat. is #4115739.
Another approach, similar to Technics, is described in the Pioneer US pat. 4476444.

 

[Nelson Pass]

Sano, et al inspired my patent #5343166 which replaces
floating voltage sources with floating current sources in
a cascoded output stage.

 

[jez]

This topology is useful for high power amps. Technics US pat. is #4115739.
Another approach, similar to Technics, is described in the Pioneer US pat. 4476444.

I would have thought that the main use for the topology would be to make it practical to build 50 - 100 W etc "class A" amps, i.e. without heatsinks that double as central heating. For true high power amps other topologies such as class G or H would be more appropriate.
The problem with patents is that they are usually as clear as mud and shrouded in legalese but thanks for the references anyway.

Nelson, Thanks for the insight into your own patented version. It seems to get the best out of the characteristics of mosfets

 

[ontoaba]

#4115739 apr-1977 is better than #4476444 for me. Lagging supply in #4476444 will only happened in poor designed digital amplifier (supply swing). Amplifier work as voltage follower already gives many advantage for its digital part.
This is my digital supply with slew limited for 8KHz bandwidth (voice amplifier):

 

[ontoaba]

I forgot it. If the supply swing in #4115739 lag, it will also happen in #4476444, so there is no improvement in #4476444.

Faster version, it will cost less in eficiency.