The Future of Audio Amplification

John Atkinson measured PS Audio's M700 monoblocks ability to produce 700 watts at 1%, and over 100 watts at 0.005%, both figures into 4 Ohms at 1K. At 30 watts into 4 Ohms, which many of us never exceed at normal listening levels, that number fell to 0.002%. From 20 to 20K at 20V, that number never rose above 0.2% into 4 Ohms; the figures were better into 8 Ohms. Not that distortion tells but a part of the story, is something not to worry about with well-designed Class D amplification.

@stevecham 

I'm talking low level distortion. .5, 1, 2, 5 watts... Very, very few class AB amps perform as well as a class A amp at single digits or fractions of a watt. Looking at a few class D examples measured on Stereophile, the low power distortion is horrendous. Looking at the Mytek Brooklyn, it makes a nifty .002% at 50 watts, but at .1 watts it's almost .02%, and the distortion waveform looks like a dumpster fire. None of the other measurements look much different for any other class D amp. That's an ungodly amount of distortion for such a low power level. Nobody can say with a straight face that kind of distortion isn't significantly coloring the sound. Most of what we call treble is defined by the behavior of amps below half a watt. 

Sorry, but even the most rudimentary 2 stage single ended class A amp can best that kind of performance. 

Class D amps sound cold and analytical to me. Maybe its all the feedback or the output filter. Meat is ultimately taken off the bones somehow.

Having said that, Class D is the future for better or worse. There is quite a bit of cost savings involved for amp makers. They can be pretty good with a tube pre amp as a bandaid.

I still have never seen a LED TV that can come close to my plasma. Plenty of people will say that LED has gotten better and surpassed plasma.

I guess it comes down to what we value and what properties are important to us. Class D and LED both win in efficiency and that is extended to form factor.

So 0.02% distortion is an "ungodly" amount huh?

Talk about dumpster fires...

Nelson Pass once said

"The first watt is the most important watt"


Cheers George