class XD - Doug Self is at it again

[jan.didden]

Hi,

Anybody seem this, any opinions? Touted as the next breakthrough in analogue amps, well, don't know about that.

http://www.cambridgeaudio.com/assets/documents/840Awhitepaper8-2-06web.pdf

Certainly the technique is far from new. They refer to a UK patent, anybody can get a hold of that?

Jan Didden

 

[SY]

Take a look at John Broskie's writeup at www.tubecad.com .

 

[jan.didden]

Take a look at John Broskie's writeup at www.tubecad.com .

Yes I have seen that. The idea comes and goes in many places, that is why I would love to read the patent application. I am always fascinated by literary attemps to present as a 'breakthrough' things that are already gathering dust...

Jan Didden

 

[AndrewT]

Hi,
I cannot fault the white paper.

There are similarities to the ClassA conversion used to linearise ClassAB push pull opamps.
Which came first?

Can we reduce dissipation in the converted opamp this way?

How does the XDpp work?
What is inside the -a stage that varies the CCS?

 

[Paul Ranson]

This may link to the patent...

http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=GB2424137&F=0&QPN=GB2424137

Paul

 

[sreten]

I cannot fault the white paper.

Hmmm........

Well its a white paper so it doesn't have to be accurate.

IMO it sets out to deliberately mislead the reader into
thinking it is applicable to EF output states, it is not,
though they haven't bothered swapping the types
of the output devices, a PNP is shown as NPN.
(figs 5, 6 and 7)

It only works well with CFP outputs.

🙂/sreten.

 

[Jan Dupont]

Have a look at this thread;
http://www.diyaudio.com/forums/showthread.php?s=&threadid=87916&highlight=

😉