Class D Technology

georgelofi you are correct about switching frequency being teh key to even better Class D amps in the future.

Have you listened to any good quality class D amps or are you judging solely on technical interpretation?

Fact is the good ones sound very good today, as good or better than most. There is plenty of reviews and such published that support that.

I can vouch for it as well FWIW.

Thing is I am over 50 and do not hear to 20khz like I know I could when younger. So I am not the best one to judge what’s happening at the highest frequencies in detail.

In general, its something of a good thing not to be able to hear up to 20khz because there is often more noise and distortion at those frequencies than music.

Check the audio frequency music chart and one can see little music happens at the highest frequencies people can hear. It’s mostly "air". That’s part of music granted but since most audio involves a compromise of some sort, this is a reasonable one.

All I know is I cannot concretely fault anything in the sound I hear from my Class D amps with any speakers up to the task of handling all they can deliver. Most people would be thrilled with them. They are the quietest amps ever, with a totally black noise floor. At least that’s what I hear.

gdhal I think one of the things switching amps excel at is delivering power and current for very short periods of time which makes for excellent detail and transients. Its a very important aspect of music that often distinguishes great sound from just good. Power and current specs alone as published probably do not indicate an amps ability to deliver power and current quickly and efficienctly for very short periods of time when needed.

One way this is refelcted uniquely with the Class D amps I own and use compared to others is detail and articulation of the bass in particular. It is leaps and bounds more articulate and detailed than any other amps I have owned or even heard. When I first heard it, I was shocked thinking my bass was gone when in fact it had leaped to an entirely different level not heard prior.

My impression is tube amps tend to be a bit softer in this regard (which some may actually prefer) and class a/b SS amps often just miss it altogether.

Class A amps, tube or otherwise are historically the ones that probably do this best, but that is changing.....

Lots of great responses. When switching frequencies are 5x higher than today's, what will be improved? Will that prevent the saw tooth waveform challenge? Or prevent the need for a low pass output filter?

What makes today's class D amps sound cold and dry? I have experienced this firsthand with an ICE Module that I once owned.

Mapman alluded to a totally black noise floor. I also experienced this with the ICE module. So far, this is the only benefit other than efficiency & power output that has been discussed and can be attributed directly to the Class D topology. Or maybe this noise floor issue is unnatural and sounds are being cut off prematurely by not allowing for decay?   

CD's have become listenable....maybe some day so will Class D's

" What makes today’s class D amps sound cold and dry?"


I’d attribute it to the high damping factor in combo with the aforementioned transient capabilities.

Mine definitely sound best with speakers that like high damping. Usually larger ones with larger drivers that are inherently harder to control.

They are more towards the cold and dry on my little Triangle Titus monitors.

Not so on my somewhat larger and more extended Dynaudio Contour monitors or any of my other much larger and more extended speakers.

They are the cats meow on my largest the big OHM F5 series 3 floorstanders with much larger Walsh style driver often cited as benefiting from monster amps with high damping. That is very true!