"D" amps, general discussion who's 1 and why?

My recent, limited experience with a Class D amp mimics quite closely that reported by several others above.

I bought a bel canto 300 to use in a second system. For fun, I tried it in my main system (Dynaudio S 3.4, Rogue 90 tube amp, Rogue 99 tube pre, Cary 303/300, Acoustic Zen cables). My overall impression was that it really is a very good amp, warm and musical across the board with a remarkable amount of detail in the mids.

After a few days of pretty careful listening, I decided the class D amp gave up depth in the harmonic overtones relative to the tube amp.

I'm not sure if that is standard audiospeak, but it is standard babble among instrument builders. When you strike a note on a guitar (or any resonant object, really), you hear the primary note loudest--the fundamental--but you also generate a series of higher frequencies that reverberate and these provide considerable depth to the sound. Guitars for some types of music (say, flamenco) and built to minimize overtone structure and others (say, for Celtic) and sometimes built to enhance it.

I decided that the bel canto offered a strong fundamental but considerably less overtone structure that the Rogue. Still, the differences were slight and I still like the amp a lot (and love that's it's "green"). But if you're after complex overtones, it might not be ideal.

I do appreciate the my 300 is not bel canto's best, and I suspect some more expensive designs or different implementations may be quite different.

Info on overtones: http://en.wikipedia.org/wiki/Overtone

Dev, I've heard the Spectrons and the new Bel Canto and think that they deserve serious consideration. I'm feeling no need to replace my Continuum 500 and I'm finding it's 1000 watts into 4 ohms and very refined pre-amp section up to the task of driving my speakers and managing my system.

Running the Spectrons bridged as mono-blocks yields astonishing power without sacrificing anything in detail and refinement.

I have not heard the Spectron or Bel Cantos in my system, but only in show systems, but I heard enough to tell me that they're making contenders for serious system.

The cosmetics of the Rowland are amongst the best for my taste. Those cosmetics are backed up with solid, close tolerance chassis design that's more than a pretty face. IMHO, you can't go wrong with Rowland, unless you're expecting your amp or pre-amp to warm up the sound. If you like neutral, transparent and dynamic, then you need to look at Rowland.

Dave

I can make my class D system sound sublime or miserable depending on what I hook my amps up with. I know, because I have done it time after time.

Every time someone brings over a glorified digital filtered digital source, the sound closes up, harmonics are lost, proper gradual decay becomes severely truncated.

Non-shielded power cords will strangle the sound. On the flip side, unnecessary insulation on speaker cables will transmit white noise.

Use ordinary power cords, good ol' hose speaker cables, and a wonder SACD player, and you have a class D disaster in the making.

Muralman1 said:

"Every time someone brings over a glorified digital filtered digital source, the sound closes up, harmonics are lost, proper gradual decay becomes severely truncated."

I'm not understanding what type of source you refer to. I see that you have a PS Audio Lambda, so you're not anti digital. (I loved my Lambda until the nylon gears on the drawer stripped after many years of usage). Could you give an example of a source that you're speaking of?

I'm using a Playback Designs MPS-5 SACD player with my Rowland with fantastic results. Of course, there are many differences between PS and Rowland (beside the 60-miles between their shops), so they're going to potentially react differently to same sources.

I DO agree that you have to be careful with ICs, PCs and speaker cables with Class D and you need to be aware of RFI and EMI when placing components around these devices. Chassis design is critical to minimize interaction, and some Class D amps are more prone to interaction issues than others.

Dave

Dcstep, as you know, the Lambda is a transport. Mine has a new wheel. Also,
it has been given a big lift in sound by Henry Ho. My DAC is an Audio Note
2.1. This too has been highly advanced with updated electronics. The DAC
has 4 NOS tubes. For tube lovers this is very essential. The tube's
spaciousness and natural delivery is faithfully preserved.

Every over and up sampling player sucks the stage both horizontally and
vertically. Also, all harmonics vanish. The difference is striking. I have had a
Modright tubed Sony SACD here, and with the same negative results.

The tubes do no good in resurrecting the SACD's performance. The digital
filter damages the tube's good qualities.

The why is easy to understand if you have any knowledge of the quantum
mechanics theory. The complete signal is an ever changing pulse of great
complexity traveling near the speed of light. There is no way a circuit can
differentiate and deftly cut out the, "distortion," without taking music
nuances with it. I can prove that here.