Negative Feedback a deal killer?

The faster the amplifier, the less this is a problem! However, faster is not the same as 'real time'. I would say that this is in the realm of 'progress' where we have an improvement over something that was done 15 or 30 years ago.

I think you can see though that if the input and feedback were synchronized, that the delay of the circuit is going to have to go somewhere. You might need a substantial memory for that. The faster you do the scan, the more memory you are going to need...

Memory is getting pretty inexpensive these days, no?

I don't know, my memory seems to be departing and I can't get it back for love nor money. A good article on Chaos is in the book on modern physics edited by Paul Davies, "What Is Chaos That We Should Be Mindful Of It?". Maybe on the web for all I know.

Hello Unsound,

I think that H2Oaudio has the full right to participate as a "private user". The reason is that he is not a designer but a person who buys mass production B&W Icepower module and installs them in his chassis (I bet makes some modifications too) and place the label "H2O" on it. Incidently ihe same is with Bel Canto, Wyred4Sound, D-Sonic and bazzilion of others buyers of ICEpower modules.

The single exception, IMO, is Jeff Rowland who while uses B&W modules yet developed his own highly sophisticated power supply and with PFC at it. My hat off to him!

Athmosphere designed his equipment form A to Z and his post is 100% accurate. He is particualrly right in: " It has also been shown that feedback, due to the time delay, actually **increases** certain distortions, namely the 5th 7th and 9th harmonics."

In his 2nd post he acknowldge that "The faster the amplifier, the less this is a problem!" He correctly noted that "... faster is not the same as 'real time' " and he is right here as well - otherwise Spectron for example would list its distortion level as zero which they are not (but very small and even order of magnitude smaller in their monoblocks but its different mechanism in force).

Also, you are mistaken, not all class D amplifiers use the same fast negative feedback as you believe. Spectron explains its method on its web-site but, for example, Bruno Putzeys (formerly of Philips) uses exactly the opposite approach and his powerful class D amplifiers (under "Kharma" name) while expensive at $25k - $30k, are said to be excellent.

Regarding what H2Oaudio wrote in relation to the capabilities of Spectron amplifiers - I copied his post and e-mailed it to them. If they want they will answer.

I believe that B&O recommends to the users of their Icepower modules not to apply them to the loads below 2 Ohms - at least until very recently so I can understand this concern... Surely, Athmosphere amplifiers, particularly since he explained the "badness" of negative feedback, cam drive such loads with ease....otherwise I will start to believe that even Athpmosphere designs are not "perfect" and he is only human ... :--) :--):--)

Cheers, life is gorgeous!

I think our ears are the best test instrument.