High end Class D amps?


Just an observation and a question. Are there 'high end' Class D amps out there that are just as good as Class A, A/B amps? I realize that's a sensitive question to some and I mean no disrespect---but whenever I see others' hifi systems on social media, all of the amps are A or A/B. There's always Pass, McIntosh, Moon, Luxman, Accuphase, etc. Where are the Class Ds? For folks out there that want more power for less efficient speakers and can't afford the uber expensive Class As, A/Bs, what is there to choose from that's close to those brands? Thanks
bluorion
OK, so in the world of Purifi, alongside Apollon (Austria)
https://www.apollonaudio.com/

or March (Australia)
https://www.marchaudio.net.au/

or Nord (G.B.)
https://www.nordacoustics.co.uk/

you're also got ATM Audio (Spain)
https://atm-audio.com/

Audiophonics (France)
https://www.audiophonics.fr/en/

Rouge (Italy)
https://en.rougeaudiodesign.com/

and Vera (Norway)
https://www.vera-audio.com/

among others.

In the US you've got VTV, so beloved of a certain member of Audiogon
https://vtvamplifier.com/

and at a very different price point LKV
https://sites.google.com/view/lkvresearch/home

A lot of these produces share the same or similar input buffers and power supplies, as well as the Purifi module, though it isn't always clear on the websites exactly what goes into each unit.  Some differences are attributable to the quality and cleanness of the construction, some (perhaps) to design, unique components, and topology.

GaN is already here with Orchard, AGD and others, while the much-delayed and much-anticipated LSA Voyager is reportedly coming soon (perhaps).

@mrdecibel What a class D amp potentially brings to the table is the ability to be neutral in a way that most solid state amps of traditional design cannot: they can be designed to lack brightness and harshness. For this reason alone they can work quite well on horns.


We are still in a period of the Wild West; there are a lot of different approaches to class D implementation and they sound different, so you have to be patient.
Danish Lyngdorf TDAi3400 is right up there with Hegel 390 in my book. Of course the former is class D. Their room perfect is actually quite stunning and it has Spotify Connect, Tidal Connect and Roon. Absolutely perfect device for folks who still want an amp and passive speakers in this day and age. (Dynaudio Focus XD powered speakers are my reference now.) 
@speakermaster, I have many of those amps you speak of. I want to try Class D, and judge for myself.
You want to find a good quality class a a/b amplifier because class d amplifiers come with a list of sound quality issues especially in the midrange and above. You can find very good amplifiers at not unreasonable prices this way and get much better sound than new.


Yeah, absolutely true! In 1995. 

You want to find a good quality class a a/b amplifier because class d amplifiers come with a list of sound quality issues especially in the midrange and above. You can find very good amplifiers at not unreasonable prices this way and get much better sound than new.


A real sleeper, very powerfull bi-polar, hard to find in good nick, and can be cheap, because it’s not in audiophile circles. https://www.usaudiomart.com/details/649216490-yamaha-p2200-p2200-power-amp/
Get hold a good condition Yamaha P2200 a bias it up 2 x as much Class-A as they can take it, they made them for band use to be very rugged.
And they use the very best, expensive, Alps Black Beauty volume pots, so feed your dac direct in and use them, a killer linear power amp.

https://ibb.co/s5T05Z5
https://ibb.co/wWtwf4r

Cheers George
So, in a nutshell....I want to try a Class D amp. I am looking for 1, that can do all of the best things, tubes and solid state, do wonderfully ( I would say we all want this ). Black background, dynamic, fast and well tempo'd, neutral in tone, no added warmth or color, a beefy power supply ( 50 years later and I still believe in this ), a well damped, non resonant chassis ( this too, is necessary ), well, something that can make my Lascalas ( modified and tweaked, of course ) sing more than how they sing, now.. I have been strictly using solid state for the last 20 years ( no tubes for me, unless a reasonably priced unit gives me all of the above ). The amps that have been in rotation, in no particular order ( all modified ) : Smart Theater Systems TA 242; an original Edge Audio M8 ( Maker Audio ); Yamaha P 2160 ( I have 6 various Yamaha pro amps ); ADA PF 201 ( the sleeper of the bunch ), and a few more. I use a Luminous passive ( they only way for me ). I want to spend as little as possible, to get all of this. Let's have it. 
A very expensive ($12,000usd) active 2 way speaker, with questionable origins for the class-D module inside.
If so then I tip my hat to Dutch and Dutch.

The 8c's cumulative spectral-decay plot (fig.6) is one of the cleanest I have measured, especially in the treble! In summing up the Dutch & Dutch 8c's measured performance, all I can say is "Wow!"—John Atkinson


Looks very to me, like it could be one of the 50 odd different subwoofer/PA modules Sanway makes, has a very similar layout to them all, time will tell when a pic of one comes up.
https://ibb.co/61hrMyJ

Cheers George
The modules in your photos are not the modules in the Dutch and Dutch
So your saying you can get a pic of the modules in the Dutch and Dutch so you can post one up???

If not then time will tell when we finally see a pic of the module, if they are not the Pascal M-Pro2 made by Sanway China, that are used in the Rowland Research and Red Dragon amps. 
We’ll have to wait and see what they are, to see if Pascal are capable of making their own modules instead of using Sanway or any others, as they have done.

Cheers George
^^ Really did you open one and look at it?

Really!! did you even look!
A blind man with "minimal" tech skills can see they are the same manufacturers subwoofer modules from Sanway who sold them on Alibaba for $100 each
Post removed 
@tvad ,
I am surprised that the AGD did not replace your existing amps. They had replaced a reviewer's SET amps in his system. So I was thinking very highly of the AGDs. Would love to hear from you about the differences between the AGDs and the Audio Notes. What was it that you did not like?
^^ Really did you open one and look at it?

I looked at your photos none of those are in the Dutch and Dutch. 
As an example the Dutch and Dutch 8c uses Pascal after testing various modules because they could get them for a better price and couldn’t hear or measure any difference. I believe Buchardt uses Pascal as well.
They are not Pascal’s modules, like ricevs fiddles with Ice modules, they are tweaked by Pascal, but are $100 Chinese Sanway subwoofer modules, as I’ve shown before with identical pictures. That Rowland Research and Red Dragon also use.
https://forum.audiogon.com/posts/2085585

Cheers George
The initial problem I had with AGD was the gimmickry of the tube enclosure, but I have to say that the pretty much universally positive reviews have brought me around.
No never heard the Orchard but the owner posts on ASR if you would like to ask some questions. He had a 10% off sale before Christmas. 
Post removed 
Then next you lot may as well just tell us to use this 6000watt!!!!! Class-D Behringer for just $600us.

Let me tell you, that on the Wilson Alexia in an a/b it was trounced by the 40 x times less powerful!!! Gryphon in dynamics and bass control. The Behringer was thin, anemic, weak in the bass and sounded like it was struggling
This post is using a Guilt by Association logical fallacy, which is that since the Behringer amp is class D and struggles, therefore all class D amps will struggle on the same load. Logical fallacies are false by definition.

 It's my understanding that efficiency has been the primary advantage and raison d'etre of class D amps since the get go. Their further efficiencies in weight, size and cost are just peripheral advantages. 
One advantage of class D amps that isn't mentioned so much is how they make distortion, and what sort of distortion they make. The distortion is mostly based on the linearity of the encoding system and deadtime used in the output section. A good deal of this distortion tends to be lower ordered harmonics. A second advantage is that if you use a self-oscillating circuit (which is an idea that's been around for about 20 years or so) then it is possible to put far more feedback in the design than is possible (for the most part) with traditional solid state designs. This is how the Purify module is capable of such low distortion. This also results in an output impedance that is so low its pretty difficult to measure. **That** simple fact means that the amp can act as a voltage source into speaker loads that are quite a bit less than one ohm, even if its power supply can't support doubling output power at full power into such a load. But if the amp is playing at a few watts (IOW: normal listening volumes) it will do so with ease.


The best measuring class D amp modules at this time are the purifi and Ncore. That's not to say others like ICE or Pascal are not good, most likely they would be indistinguishable in properly designed implementation. As an example  the Dutch and Dutch  8c uses Pascal after testing various modules because they could get them for a better price and couldn't hear or measure any difference. I believe Buchardt uses Pascal as well. There is no reason class D amps should be expensive at least by audiophile standards unless the company uses high priced case design, name recognition,  added coloration through implementing purposeful distorion by way of tubes etc... , more features like the Nad M33, room correction,  dac, streamer. 


     I’m with twoleftears, I’m always up for a thorough discussion on all the class D amps that owners think are noteworthy. I’m very satisfied currently with my 6 year old pair of D monoblocks but I’m constantly curious about the latest examples and I’m very interested in reading about opinions on them, whether from owners or those that have personally auditioned them.
     I became a member here back in 2013, and if I recall correctly, that’s about the time that the newer, very high quality class D amps began becoming available. At that time, I remember there were a lot of forums from owners of various brands of these very high efficiency, small, lightweight and relatively affordable class D amps that were being extolled as also offering very good full frequency range performance.
     These claims of very good full frequency range performance seemed to be a major point of disagreement on the forums at that time. The class D naysayers were typically proclaiming they were only suitable for bass amplification, sterile midranges lacking body along with bright and fatiguing treble.  
      Even as long ago as 2013, the class D amp advocates were proclaiming many of the latest D amps were much improved, powerful, dynamic with high quality full range performance, including the vary important midrange and treble frequencies, in their systems with a variety of speakers.
     After reading many of these early forum discussions on the merits of class D amps, I was a bit perplexed and frustrated. Were these amps as good as described by many? Why was there such a polarization of viewpoints, with avid opinions on both pro and con explanations? Were these class D amps, being examples of newer advancements applied to a somewhat older technology, any good or not?
     I finally realized I was unlikely to receive any objective answers to my questions by simply reading Audiogon and other audio forums about them. So, I decided I needed to just pick out a reasonably well performing and priced class D amp, purchase it on a free 30 day in-home trial basis and determine the technology’s viability for myself in my own system and room.
     I bought my initial class D amp, a Class D Audio SDS-440-CS high powered stereo unit from a company in California, based on its generally favorable reviews and reasonable $540 price.  To state I was impressed by this relatively small and lightweight amp would be a serious understatement. It easily outperformed my 2 prior decent quality and high powered class AB amps, an Aragon and a McCormack, in driving my Magnepan 2.7QR main speakers I used at that time.
     So I finally had my answer, even a budget class D amp performed very well in my own, very important just to me, opinion. I was definitely impressed, but somewhat unexpectedly, this only made me more curious about the practical applications of this new to me class D technology.  As a result, I fairly quickly decided to purchase a few more D amps to see just how good higher priced and quality examples might perform. I next bought a stereo Emerald Physics EP100.2SE unit and then a pair of monoblock D-Sonic M3-600-M amps.
     My main points? The D-Sonics are the best performing class D amps I’ve used to date, Just like twoleftears, however, I’m still curious about new advancements in class D amp technology in general and I welcome any reasonable forum discussions on the subject.
     I also suggest, for any others uncertain about the performance level provided by class D amps in general, that individuals don’t rely on taking mine or anyone else’s opinion on the topic.
     Instead, I recommend individuals take advantage of one of the numerous class D amp company offers, of no risk free in-home trial periods, and just decide on the merits of the class D amp or amps for themselves.

Tim
@phd


I had a HCA-2 and still have a PSAudio GCC 250 (moded as new by Chris Johnson) that I bought when it first came out. I then had several W4S models > Emerald Physics 100.2 SEs with upgraded fuses > Audio Alchemy DPA-1> PS Audio M700s, and now, and for the foreseeable future, my awesome EVS 1200, though I am still in line for the Voyager GaN


Stereophile has a very nice review of the $2500 Marantz 30 integrated

If you think of the number of people on the planet, who are audiophiles or enthusiasts, and among those who own speakers whose impedance dip to less than 2 ohms - that must be 0.01%? Don't know. But for the rest of us folks the Purifi would be more than sufficient.
+1 @twoleftears 
Would love to hear from other Purifi owners experience who own Nord or March.
I have a March Ncore P502. It's a very neutral amp which to me is the best thing you can say about an amp. Never heard an Apollon but they measure very well and inside they look tidy and well laid out. 
Evidently, it was too much to hope for some reasonable discussion of the virtues of the Apollon, with perhaps some owners of competing brands like Nord and March contributing also.  But so the 'gon goes.
If speakers should strive to be efficient why shouldn’t amplifiers? Efficiency is always a good thing. 

Even worse, efficient speakers tend to be big heavy and bulky. Efficient amps the opposite.



     It's my understanding that efficiency has been the primary advantage and raison d'etre of class D amps since the get go. Their further efficiencies in weight, size and cost are just peripheral advantages. 
     Their further relatively constant improvements in performance and sound quality are, in strictly technical terms, just 'friggin breasts'!

Tim
If efficiency is the definition of a perfect amp class D is closer than any other. 

     I've actually grown to like georgehifi and consider him similar to an old dog that's just become a fixture around the Audiogon shop. 
     Sure, he barks at predictable times about predictable topics, grudgingly respects and roots for class D while constantly throwing shade on it, poops inside the house a bit too often, probably has fleas and is generally about as useful as nipples on a male mouse. But aren't these some of the qualities that make him so endearing and lovable, too? 

Tim
@jaytor - For sure. I wasn’t sure I read the spec right . . . the output impedance of the 1ET400A is specified as <65μΩ @ 1kHz.  Sixty-five millionths of an ohm. The output terminals will add more impedance to the circuit than the module itself!
@djones51 - if your definition of an ideal amp is a perfect voltage source, meaning an amp with zero Ohm output impedance, then a class D amp gets closer to this ideal than any other amplifier topology. Class D amps have much lower output impedance than class A or A/B amps. 
You make it sound like the Wilson Alexia is the most popular speaker on the market.
No, I use them as my friend owns a pair, he's reviewer, so we get many amp to try on them, and they are one of the the most difficult speaker to drive,  especially for Class-D,  as they have an EPDR of just 0.9ohm in the bass.
If a linear amp was a perfect voltage source it would double every time the impedance halves. So if it does 500 watts at 2 ohms it will do 250 watts at 4 ohms and 125 watts at 8 ohms. It's not that it's important it puts out no more it's that even if we were talking about a perfect linear amp it couldn't . 
You make it sound like the Wilson Alexia is the most popular speaker on the market. How many of these has Wilson sold?

 I’ve owned a lot of speakers over the years and none had an impedance curve that dropped below 2 ohms. If you own Wilson Alexias then maybe the class D amps that have been discussed aren’t the best choice. But if I owned a speaker this expensive, I probably wouldn’t be driving it with an amp that costs well under $10k. 
Then next you lot may as well just tell us to use this 6000watt!!!!! Class-D Behringer for just $600us.
I didn't say that; I didn't say that all amps are equal, nor that they sound the same, nor that they are of the same quality.

I did say that I fail to see any relevance to this "doubling" business that has become an audiophile touchstone. Those who claim it is important seem to resort to pseudo-technical handwaving. Maybe there is a reason, but I've never seen it laid out in valid technical terms.

And YOU didn't answer MY question: If an amp can put out 500 watts at 2 ohms, why is it important that it put out no more than 250 watts at 4 ohms?
It doesn’t matter. It puts out 500 watts into 2 ohms. That’s enough for most users. I consider "doubling" an irrelevant factor.

Then next you lot may as well just tell us to use this 6000watt!!!!! Class-D Behringer for just $600us.

Let me tell you, that on the Wilson Alexia in an a/b it was trounced by the 40 x times less powerful!!! Gryphon in dynamics and bass control. The Behringer was thin, anemic, weak in the bass and sounded like it was struggling
https://www.bhphotovideo.com/c/product/1427354-REG/behringer_nx6000d_6000_watt_class_d_power_amplifi...
George does not understand class D and even though I have tried to educate him he refuses to learn.  I expect some statement now about EPDR. It will be wrong.
@georgehifi -- It doesn’t matter. It puts out 500 watts into 2 ohms. That’s enough for most users. I consider "doubling" an irrelevant factor. Does the amp generate enough power for the intended use? If so, it’s a good choice (as far as power goes). If not, it’s not.
By the way, your statement is logically equivalent to saying that if an amp does put out 500 watts at 2 ohms, it is somehow lacking if it provides more than 250 watts at 4 ohms or 125 watts at 8 ohms. Why should that be a problem?