Do ClassDAudio Amps Have Proper Decay Of Notes?

The trouble with Class D is the frequency of the switching noise, (the saw tooth you seen on the top of this bandwith limited 10khz square wave)

http://www.facstaff.bucknell.edu/esantane/movies/10kHz10v4ohmsquare.JPG

In the future when the components are faster and the switching noise is much much higher then this noise can then be filtered out effectively and then not effect the audio band.

At the moment it will always influence the sound quality of Class D as it’s too close to the audio band not to effect it after being filtered out.

Manufacturers either filter it out low so it’s not there but the trouble with that is it’s filtering way down to 5-10khz, into the audio band, which ruins any decay/harmonics of the music signal.

Or they filter it up high,, and let through the switch noise to the speakers, this then sound hard and etched, some go for the middle ground with a bit of both.

Cheers George

BTW: that "future" much higher switching frequency I talked about above, is closer than we think.

Technics with their SE-R1 are showing vision by developing their own much fast switching frequency transistors, double the norm that’s around now. It would still be better if it were 5 to 10 times faster, but it’s small steps to a good end for Class D. Then you’ll see me sell my big hot power hungry boat anchors.

But the amp is expensive at around $22,000.00usd I believe.

http://www.technics.com/us/products/r1/se-r1.html#overview

And you can bet they’re not going to sell those transistors to just anybody.

Just one reviewers words of what he heard:

"Listening to tracks that we’ve heard 100s of times — and on excellent systems at that — is now a revelation of once hidden nuance and detail. Not only are we hearing things we’d never heard before, we’re hearing it in a way we’ve never heard it before. A music system that sounds like a live performance is a tough goal to attain, but Technics’ flagship nails it."

Cheers George

While I've seen graphs that dramatize a digital waveform I honestly can't hear anything that would suggest a stair stepped waveform or "digital noise" from any of the switching amplifiers I've listened to

Yes as Ralph has corrected about class D classification not being digital.

Also the "digital noise" I believe is an analog switching noise and is around 600-800khz, too low to be effectively completely filtered out of the audio band without effecting it with early hf roll off.

The new Technics SE-R1 with their new proprietary transistors takes this switching noise up to 1.5mhz which is a step in the right direction.

But from those in the know the switching noise needs to be up around 3-5mhz to make the filtering completely effective, and not to intrude into the >audio band at all, then it will take Class D into proper hi-end amplification.

That’s when I’ll sell my hot inefficient heavy boat anchors and also go Class D, and the smart linear amp manufactures will have their fingers on the "sell my business button" before this this technology comes along for anyone to source these new super fast transistors, or compete with the Chinese.

Cheers George