Class D Technology

savdllc,

     You stated: " but if one is chasing greater efficiency than Class A without sacrificing as much fidelity as Class D tends to do, Class G and H amplifier tech would seem to be the best choice."

     This statement implies that class D requires you to sacrifice significant fidelity when compared to class A/B.  As a user of various decent quality  class A/B amps exclusively for about 30 yrs (beginning with Adcom and then McCormak and  most recently Aragon) before trying various good quality class D amps (beginning 2 yrs ago with a budget ClassD Audio SDS440SC  then an Emerald Physics EP-100.2SE and currently D-Sonic M3-600-M mono-blocks), I can assure you I never felt I was sacrificing any fidelity with class D.  

    With all 3 class D amps I actually experienced quite the opposite; immediately noticing significant improvements in noise level, bass response, mid-treble fidelity being very similar to class A/B with my initial budget class D and clearly superior to my former class A/B amps with my admittedly better quality most recent class D amps.

     I know there are many here on Audiogon who have discovered  switching to class D is all gain with honestly no pain.   I'm concerned that comments like yours, and other posters earlier in this thread, may give readers the false impression that switching to class D involves some sacrifices in sound quality.
      I want to make it clear to everyone considering a switch from class A/B to class D amplification that these sort of comments may have been accurate for some early lower quality class D amps but are definitely not valid for current good quality class D amps.  

     Once you've experienced the extraordinary improvements a good recent class D amp will make in your system, you'll begin to realize how inaccurate, no longer relevant and simply untrue these types of comments are.    

     I can only rationalize these sorts of comments by assuming that these individuals have obviously never auditioned a recent good quality class D amp in their system or anywhere else.  Although it's possible  they're just parroting comments they've heard years ago about early examples of class D. 

     I'm grateful I ignored these class D myths and opted for an open minded home trial and suggest others do the same.

    Concerning class G and H, I have never heard either but I'm interested in hearing them.  Being an extension of class A and A/B amps, however, I would expect them not to have the same advantages of reduced weight and size that class D allows.

Thanks,
  Tim

Classes G, h have the same advantages of reduced weight and size that class D allows to a lesser extent.  The power supply is "variable" based on the signal.

BTW, is the highly rated Benchmark AHB2 amp considered Class D?

I'm concerned that comments like yours, and other posters earlier in this thread, may give readers the false impression that switching to class D involves some sacrifices in sound quality. 

Class D did exactly that at my house.
   

I want to make it clear to everyone considering a switch from class A/B to class D amplification that these sort of comments may have been accurate for some early lower quality class D amps but are definitely not valid for current good quality class D amps.

Not sure what you consider "current good quality class D amps" but to confirm, my comments are based solely on comparisons with the Ncore NC1200 Acoustic Imagery Atsah monoblocks ($10K/pair).

Once you've experienced the extraordinary improvements a good recent class D amp will make in your system, you'll begin to realize how inaccurate, no longer relevant and simply untrue these types of comments are.

Again, not here.  My evaluation started with four amplifiers, all of which I owned and the Class D Ncore amps were the first eliminated.  There were indeed sonic trade-offs and the Ncore amps did some things quite well (bass, tone, power, body and lack of noise).  For some, those attributes at would be enough since they were enjoyable to listen to but, for me, there was a missing musicality factor that ended up being a deal-breaker, at least in my system and to my ears. The Atsahs, like Merrill's Veritas, use the stock NC1200 amplifier and power modules.  I would like to hear those amplifier modules with a linear power supply as in Theta's Prometheus and I would also like to hear the NC1200 modules with an input buffer, as some are using like, I believe, Mola Mola in the Kaluga.
   

 I can only rationalize these sorts of comments by assuming that these individuals have obviously never auditioned a recent good quality class D amp in their system or anywhere else.  Although it's possible  they're just parroting comments they've heard years ago about early examples of class D.

Again, be careful painting with a broad brush.  Some of us have indeed auditioned and even owned amps considered to be "good quality Class D amps."  I ended up voting with my wallet. Class D amps are obviously getting closer to sounding as good as really good Class A or AB amps and in some specific implementations may sound better.  The Atsahs were good sounding amps but they were not as good-sounding as my other options.  There have been many positive reviews of the NC1200-based amps but for another perspective, read near the end of the linked review of the Mola Mola Kaluga.
http://www.monoandstereo.com/2015/08/mola-mola-makua-and-kaluga-review.html

mitch2

Isn't the term "musicality" subjective??? Meaning not everyone will hear it the way you do......

Absolutely, "musicality" is indeed subjective . I am not trying to convince anyone. My intention is to point out the inaccuracy of making broad generalizations about folks here who still like the sound of their Class A or AB amps better than the Class D amps they have compared against, and how that doesn’t necessarily mean they are only comparing against old Class D technology or less expensive Class D implementations.

I may not have defined "musicality" adequately but would add, the sound of the Mola Mola Kaluga described in the review linked to my prior post is not unlike what I heard from the Atsahs. Again, I thought they were good amps, just not as good as my other options.