Class D Technology

sean I think that is a particularly strong application for them that may be hard to match as cost effectively elsewhere.

I think they are also a fairly safe bet to be able to technically drive most any speaker well up to a certain volume depending on specific amp used. Meaning the ability to get teh most possible out of most any particualr speaker.

That’s not to say I would even think they always will sound best.

For example, I anticipate my Triangle Titus monitors, which are small but known to be very tube amp friendly, would sound better (within their limits) with a good SET OTL or push pull tube amp. I plan to try taht someday soon and see.

My Bel Canto amps do a great job of driving the Titus on paper technically, and still sound quite good together, but the sound is somewhat lean in comparison to the others. I have found that corner placement with teh bass reinforcement that offers does help a lot.

Also I would say that in general the best Class D amp demos I have heard over the years also tend to be with bigger and better more full range speakers that have no problem delivering flat bass to the lowest octaves when driven well.   That's one of the hardest things for any amp/speaker combo to do.  Just like Class D amps excel for use in Subwoofers, they also excel for use with speakers that require no separate powered sub to sound great when driven well.  

anyone care to list the best sounding Class D amps?

Thanks mapman. That is consistent with the new KEF LS50 active monitor. It uses Class D for the bass and Class AB for the highs. 

Non-linear & lots of distortion that needs to be cleaned up with an output filter.

I don't understand what you mean by that.  Class D is extremely linear.  Class D modulator, converting voltage to duty cycle, resembles Delta-Sigma D/A converters (principle of operation is the same) that are extremely linear.  Output filter, Zobel network,  is only used to obtain average value and reduce amount of noise on the speaker wires (that is inaudible).  Like with any amp - don't guess and just listen.  I like sound of my small class D Rowland amp.  I like imediacy, transients, liquid midrange, low noise floor and composure under loud passages (regulated power supply).  The only problem I had initially was lower midrange.  It was a little thin sounding.  I replaced speaker cables with Acoustic Zen Satoris and lower midrange came back.  Cello sounds like cello and I can hear "chestiness" in male voices.  Perhaps the question is not whether class D is worse or better than class A (Jeff Rowland makes some wonderfull class D amps), but rather if it is better for you, for the money you can spend.  Switching technology is very promising - just look at SACD - pretty much the same as class D.  I agree with George that switching frequency should be increased, since 50-60kHz bandwidth limitation introduces around 20deg phase shift at 20kHz (causing wrong harmonics summing), but I'm not even sure I can hear such nuances.  There are many highly praised amps that have similar bandwidth, I'm sure.  

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?

Yes the new Belcanto 600 monoblocks, they were the best of the Class D's I've heard so far, but still didn't convince me to go to the dark side yet.

In the future when the switching frequency is up around 3-5mhz then the filtering can do it's job properly without it's effects influencing the audio band.
The Belcanto 600's did a series of output filters to counter this, but it has it's own set of problems.

The Technics are up to 1.5mhz but you pay for this $$$$$

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

Cheers George