My experience is similar to some others here and well-stated by timrhu, I stopped with the almighty NCore amps. They almost always sound impressive at first listen, clean, quiet, and cool running. For me though, they begin to show their true sound after a month or so. I've given up on them. In my case, it was a fatal flaw similar to that described in the review of the Mola Mola Kaluga by Mono & Stereo. I had no problems with high frequencies and for me it was more about inner dynamics and the presentation sounding whole instead of like a grouping of individual sounds...sort of like the difference between a band playing live and the same band creating a recording by dubbing one player over the other until finished. Sorry it is hard for me to explain, but the Class D Ncore just didn't sound as musical or involving, although they were clear, quiet and had excellent bass. I really wanted to like them best but kept thinking something was missing. So, what sounds better? The Class D I owned for over a year was the Acoustic Imagery Atsah, which is the Ncore NC1200 modules in CNC-milled aluminum boxes, very similar to the Merrill Veritas. At that time, I owned four amps. What I liked better were; Lamm M1.2 Ref - Class A McCormack DNA-2 LAE with full SMc modifications - Class AB Clayton M300 - Class A I still own the last two and in my system playing Aerial speakers the Clayton monos (300/600 wpc all in Class A) were easily the best sounding of the bunch IMO. |
"It’s like baking a cake" Actually, it’s more like frosting a cake that someone else baked. When I owned the Atsah’s (same Hypex Ncore modules as the Veritas, also in milled aluminum boxes) I had the opportunity to try different wiring harnesses between boards and from the boards to the binding posts. I tried high quality wire from Harmonic Technology (individually insulated multiple strands of OCC copper), Jupiter (high quality copper in cotton) and others and the differences between changing about 5 inches of wire did not even approach the difference between chocolate and vanilla frosting on the cake. I agree Cardas wire is good (I have Lundahl transformers using Cardas wire that sound very good) but I doubt it changes the basic signature of the amplifiers, and certainly no more than changing speaker cables. One thing Merrill does that I like is they apparently (not confirmed because I know of no posted pictures of the insides of Merrill’s amps) solder the wire directly to the boards rather than use the generic plastic connectors intended for the Hypex boards. However, I would have an issue owning a component where the manufacturer is so concerned with people looking at how it is constructed that they would not allow the end-user/owner to even open the box to change the fuse. |
Back to the OP's question (really two questions);
So my question is, if it weren't for efficiency & power, would there be any reason to own a Class D amp? Do they beat Class A in any other categories that count for sound quality? The obvious reasons to buy a Class D amplifier are power per dollar, efficiency, and form factor (i.e., small). They should also work well in powered speaker implementations. From a sound quality viewpoint, some, like Guido who posts here, have had good luck with cutting edge designs from Rowland and Stereophile certainly gushed over the Theta
Prometheus that uses NC1200 modules with a linear PS. However, even the Mola Mola that 6moons praised has received some responses that it is not quite ready to compete with the best. Based on my singular experience with a pair of Ncore NC1200 monos, the one sound quality based reason I can think of that somebody may like Class D over (high quality) Class A is low noise. The Ncore NC1200 amplifiers were dead nuts quiet. My Class A Clayton amplifiers are not as quiet as the Ncores but they are certainly no noisier than other Class A and AB amps I have owned, quieter than most, and quiet enough that noise is a non-issue. Sonically, the NC1200 amps came close to the Claytons in several respects such as having a nice tonal quality and full, powerful bass, but even in those strength areas, the Class A Claytons offer a bit more realism and enjoyment. In some other areas, such as high frequencies and soundstaging, I find the Claytons to be clearly better. With respect to sound quality and listening enjoyment, of the amps I have owned, I would rank the NC1200 amps about fourth. |
ultimate transparency / cleaness / hifi is no more their goal these days Those never were my goals. Although resolution and a quiet background (similar to what you may mean by transparency/cleaness) are expected attributes in higher end gear, excellent tone, dimensionality and dynamics are more important to my enjoyment and, in my experience, it can be hard to find all three in a component. |
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 |
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. |
All is good Noble100, I can certainly understand how folks like the Ncore amps so much since, in my system, they did a lot of things right
(bass, tone, power, body and lack of noise). However,
even with very good and highly regarded amplifiers, seemingly minor sonic characteristics can affect one's level of satisfaction with how their system sounds. Everybody has their own personal "right" sound. I really wanted those to be my "final" amplifiers because they had the desirable combination of high power, high input impedance, balanced operation (my system is fully balanced), small size, low energy usage, low noise, and the ability to remain powered up all the time. Unfortunately, my preference was for a pair of large, heavy, and hot Class A amplifiers. |
Guido, in your posts you have indicated the Merrill Veritas are among the Class D amplifiers you enjoyed listening to and that do not display, "any displeasing high frequency artifacts or limitations." I owned the Acoustic Imagery Atsahs, which should be a close sonic twin to the Veritas. Unfortunately, I cannot confirm the differences between the two since Merrill does not condone opening their amplifier casework and looking inside and I can find no posted pictures of the insides of a Veritas amplifier. Based on my review of online information, the differences between the Veritas and Atsah amplifiers include, hook-up wire and binding posts, individually milled spaces inside the Veritas chassis - although both use solid milled aluminum casework, soldered wire connections (Veritas), and the use of the Hypex input board (Atsah). I would not expect these differences to substantially, or possibly even noticeably, affect sonics as perhaps would items such as a linear power supply, input buffer or input transformers. One listener over at Whatsbestforum who tried both amps (and ended up buying Mola Molas) posted this; "They are sonic siblings. It would be silly to argue otherwise. The basic designs are the same. They both use the same unmodified NCORE SMPS and NCORE 1200 module from Hypex. Sonically, I would give the nod to the Veritas. They are a little more resolving, but not by much and I don't have them side-by-side. So, if an Atsah owner calls me out on this, I won't fight back." So, proceeding on the assumption that by owning the Atsahs for over a year, I have a mostly reliable understanding of how the
unmodified SMPS1200 and NC1200 modules sound, whether in the Veritas or Atsahs, then my question to you is, would you describe what you hear differently between the Veritas and the Rowland M925 amps that have earned the M925s a permanent place in your system? - Thanks |
Guido, Thank you for the detailed answer to my question yesterday. One attribute you stated, Aliveness of "black" background... Also called the sound of the silence between the notes... Or the reproduction of ultra-low level information. ...reminds me a bit of what I found missing from the NC1200 Atsahs, at least compared to my other amps. I am curious about what JRDG has done to bring out the best of the Ncore amplifier module but there are so many features incorporated in those amplifiers, over and beyond the stock Ncore modules, it would be impossible to isolate the specific contribution/benefit resulting from any one of the features. I hope to hear a pair some day. |
Their literature says Class D ICE output stage and MOSFET input stage |
Thanks Tim for the positive comments on D-Sonic. I am soon going to need to replace an aging 1984 era NAD 2140 that powers my outdoor system and I have been keeping an eye on D-Sonic for that purpose. |
if it weren't for efficiency & power, would there be any reason to own a Class D amp? Class D amps rock the category of watts per dollar, which makes them a good choice for powered subwoofers where the goal is control and damping of large drivers while imaging and spatial information doesn't matter. Do they beat Class A in any other categories that count for sound quality? Power and control, both of which are harder to achieve economically with Class A. Otherwise, Class D does not beat Class A in my experience comparing Class A Lamm M1.2s and Clayton M300s with Class D Ncore NC1200 via Acoustic Imagery. I owned all of those amps and compared them directly in my system over an extended period. The Class A amplifiers were way better at portraying music naturally and believably, which seemed to relate to the spatial representation of the individual sounds and instruments. The NC1200 amps also did not beat better Class AB amps, IME. Better sound quality seems to be the current goal of Class D designers, with pockets of manufacturers and owners claiming that certain topologies and products are getting closer or achieving the goal but so far, the marketplace has not seemed to fully agree in the long term. |
Tim
Class D absolutely rocks watts per dollar (except of course for
gallium-nitride transistor versions) so if they get the other stuff sorted they will be hard to beat. My only comparisons were the Acoustic Imagery Atsah which are a Ncore NC1200 implementation that I owned for over a year, and H20 amps that I had here for a very short time. I was initially impressed with the NC1200 Atsahs because of their dense tonality and hard hitting bass but after a longer period of listening and comparing there seemed to be something just a little off, or missing. It took me a bit to figure out that my issue was with spatial cues that lead to realism. The NC1200 amplifiers were not inexpensive when they first came out and even the Atsahs at the lower end of NC1200 were still $10K.
As to Class A, that doesn't necessarily get everyone to the finish line either, even if you neglect the heat and electrical costs. So much is related to amplifier-speaker synergy as well as the types of music preferred by the listener. In my case, the Lamms were not powerful enough to adequately drive my power-hungry Aerial speakers on the rock, pop, and blues music I most often listen to. The Claytons were much closer at 300wpc and they were just outstanding on tone but still displayed a bit of reticence on particularly dynamic passages. There are always trade-offs. My upgraded SMc/McCormack Class AB monos finally gave me enough clean power to properly drive my speakers through the most dynamic music, while also getting me sonically close to the dense tone, staging, and extension provided by the Class A Claytons. They are not necessarily better amplifiers than the Claytons but for my situation, speakers, and musical/listening preferences they are. |
