The NAD M33 will cancel your complaints about Class D

There are many reasons to like one type of sound over another. Even among what are considered very good amplifiers there’s a broad range of tastes and preferences among audiophiles. Just ask a SET aficionado!

However, no class is more maligned, inappropriately, than Class D. To hear some regulars tell it, Class D sound will thin your blood, make your teeth fall out and ruin your enjoyment of just about everything because it sounds so (fill in a lot of tropes from the 1980’s here).

I’ve been listening to NAD’s prior collaboration with Bruno Putzy and I can tell with some confidence that none of those tired old tropes apply. For reasons related much more to tonal balance than anything else, I’m sticking with Class A/B in my main system, but with the introduction of the next gen Anthem AVR receivers and the NAD M33 I may be making the switch back to class D.

You don’t have to like the M33 or the Anthem’s but can we at least agree that it’s time to retire the old guard of reasons not to buy Class D? Lets lay those poor phantoms to rest.
If I were in the market I'd be giving a serious listen to Class D.  Why the heck not?  And if it causes the weeds in my garden to shrivel up, so much the better.
These are good products but don’t change anything.  Some will listen to Class D and buy it and others still won’t.  So what?  That’s been true for quite awhile.  People can buy whatever they want or not.    Newer  technology  will always tend to get better over time.  Some will never buy in because they prefer something else. 
i recently got a devialet all in one integrated, the sound is spectacular
I am using a Nuprime ST10 class D and have no complaint. 
I don’t pull enough watts to justify a class D amp. Just to be buying a new amp? Really?

No thanks.
I have been using class D for almost five years now (Devialiet 400 mono block) and I haven't heard anything better in the class A/B till now.

I believe it is a matter of taste rather than good or bad. 
I have had two Devialets, previous NAD generation and various other class D bits and pieces. Can’t stand them for that very reason: tonal balance. Nothing wrong with them. So I disagree. D is not yet there. High end is not about class D yet. 
Admittedly I haven’t heard the M33, the latest Lyngdorf or any other Eigentakt hardware. But reading Darko’s review (not first person experience, agreed), one word strikes a cord: out of the box the amplifier sounds a bit lean. Darko had to make good use of Dirac to get it to play to his taste.

And I remember my days with Devialet and WA Duettes. One had to buy the garden hose variety power cord because Devialet was very fussy about mains quality. A power regenerator would be even better. Only Transparent Reference would do as a digital cable. A lot of people would vouch for Entreq grounding products. Silly expensive speaker cables (I had to get to 15K Transparent Reference XXL to bear the sound) but even then, sitting down, I would end up dissecting and reasoning, not enjoying the music. 

A clear trend emerged where people would go to great lengths and spend silly money to convince themselves that this class D or that was the bees knees and they really enjoyed the sound when in fact they would equalise, filter and tune the sound to try and compensate for the inherent class D flaws. 
Also the Devialet was an absolute nightmare for all other Hi-Fi components - I think it was injecting a lot of junk in the mains. Even my TV was suffering, until I got a power plant. 

Someone hasn’t heard anything better than his/ her Devialet. Have they tried a Gryphon Diablo, a Pass Int or any number of other serious integrated A/B amps? Maybe and of course in the end it’s all a matter of taste.

 I would certainly love to have an anorexic, slim, cool and power efficient amp, possibly an all in one solution to get rid of all the big, heavy and geeky looking boxes in the lounge (no, I am not into HiFi porn). Devialet would have been my ultimate Hi-Fi system if it would have delivered ultimate sound. Everything else was superb, if bling. I sold it within 6 months of trying, really trying to convince myself I was enjoying its sound. 
I auditioned both the Gryphon Diablo and Aavik U-300 when looking for a top class all in one solution. In the end I went with the Aavik. It was close and had I just been looking for amplification alone it would have been even closer. The DAC and Phono stage in the Aavik were better however to my ears.

Both are fabulous products.
Lets lay those poor phantoms to rest. But Phantom, the Devialet ones are class D, well Analog Digital Hybrid (ADH) amplification. My Kii Threes are class D designed by Bruno, digital is the future and the future is here now.
Happy Thanks giving,the music will tell the story,get what sounds good to you,and do the research!
Dsonic has a lot of measurements for their Class D amps posted on their website.  I was impressed!

The map is not the territory.

The measurements are not the sound quality.

I think, from expensive experience, that the NAD M33 will not convince me that Class D amplification is better than or equal to the better class A/b amplifiers.

If forced at gunpoint to put my life on it (for some strange reason), I would stake my life on it as being the outcome.

We all hear differently., we all see differently. We all have different physical skills. we all think differently.

Your chess game skills or skill tests or skill sets, and pshycial aspects as related to the intangible aspects of mind, and bodily capacities, are not mine.

One given person’s assessment of Class D or comparisons of any kind..(in reality, not human projection)... will stand little to no chance of satisfying all persons, or even a majority. That is a logical outcome of the points at hand in the given equation.

Humans are not a number on a sheet of paper. They are a steaming living writhing heap of variables within themselves, never mind when trying to compare them to one another.
Over time, commonalities may emerge. Believing in those commonalities is a general good thing but in the specific, factualizing them as a universal truth, is a not just a mistake but a logical fallacy that humans tend to take on. Instinct and emotions manipulating the formation of logic. the kind of mistake that humans tend to make. the herd part of the mind, it is.

eg, most people get their understanding of consciousness quite wrong and understand it in rather simplistic and incomplete terms. that their idea on/of human awareness are.. well, their awareness itself. Which is, in many cases, horrifyingly incomplete but...100% perfect to them ( Gödel’s incompleteness theorem as a mind set).

Logically, when analyzing humans and how they work or how the gears can be no other way. Everyone tends to think or pattern their thought formation on being a complete person with 100% skill sets of mind. Not true. It’s just a thing that human minds do. We work with the tools we’ve got to the point that we project them as all of reality - both inner and outer. That sort of thing is unconscious instinct, not logic, or is it representative of actual reality. It’s tied to the ego loop of the voice in the head. Part of the wiring of the fleshy box, it is. Our complex ’integrated with others’ norm, is outward looking, never inward.

Then the aspect of how the mind suffers Pareidolia on not just the visual front but it is known to exist as a hardcore hardwired norm in the world of human hearing.

Where we preload sound shapes into the mind and tack them on to the beginnings of sounds heard, so we can process sound in real time. Eg, when we dance to the beat, it is an act of anticipation, like throwing a rock at a moving target.

We (individual humans), as a norm, don’t hear a timed cymbal, what we get.. is our norm of a cymbal recording, that overwrites the incoming sound with the impression of a norm that is stored in our minds. this is how we process speech and words in real time.

Defeating that system, is a core point in realizing where fidelity in audio - begins and ends. To stop processing our own inner soundscapes, and open our minds and ears to hear the new, in detail and micro detail.

Added to that, is varied levels of intelligence, varied levels of sound libraries, varied levels of processing power, varied levels of native levels of hearing quality and capacity..and more. Just to describe one human vs another.

Next it is suspected that hearing capacity,being tied as a fundamental in the mind, has a variance, between individuals, that is akin to that of intelligence. Where a variation of 5 IQ points means either half the cognitive speed, or twice the cognitive speed, depending on the direction of the differential.

Nor is the idea of human intelligence and a given associated hearing package as being the same, in a given person vs the other. Some might be considered to be mentally less capable in numerical calculation or whatnot, but have superb hearing skills, or vice versa.

Variation in humans, in all ways and directions and combinations of sensory skills, is the norm. Eg, one might be terrible at articulating their disagreement with Eric, but also be hearing the differences clearly.

In other words, the quality of the argument for Class D, by a group or individual, does not in any way mean that it is sonically superior. Or vice versa.

The argumentative map is not the argumentative territory.

So no, Eric, this NAD amplifier, historically speaking and in just the human points of analysis..never mind the science... and..overarchingly, in all possible logic that is real --it is very unlikely that it is going to change my mind.

I reserve the right to be wrong (logic dictates that this has to be in place), but be advised, it is a very very tiny corner or window. So tiny that it is very unlikely that the NAD amp will fit through it.

Eg, if you sit here and call the M33 perfect, or the pinnacle, or better than all of the amplifiers that have come before (which you are stepping into doing).... then I’ll be forced to counter and balance such missives out...and explicitly cut NAD and Bruno - to the bone. Which I have no desire to do. I wish Bruno the best, and to have him continue onward and upward.
i have heard excellent class D amplification.  stunning with the right music and recordings.  
for me it has one fatal flaw, an inability to handle compressed music and music with intentional distortion, e.g. arcade fire, sonic youth, flaming lips, spoon, tame impala.  
there is an additive distortion effect to this music that makes it intolerable to my ears.  tube amps handle it ok, class ab a little worse but class d not happening.  
Someone hasn’t heard anything better than his/ her Devialet. Have they tried a Gryphon Diablo, a Pass Int or any number of other serious integrated A/B amps? Maybe and of course in the end it’s all a matter of taste.

yes - feel free to click on my system - been at this for 40+ years

i do use power conditioning and decent power cords...

i have not liked most class d stuff i heard in the past - i remember levinson monoblocks in 2008 - bought them and resold them within a week

but the genre has come a long way -- is it as good as my audio research reference 75 or hegel h20, pass aleph 3 or audiosector patek? no, not in the most critical listening, but it is not that far off, and importantly, it is very listenable, no nasties and some very notable strengths
i have heard excellent class D amplification. stunning with the right music and recordings.
for me it has one fatal flaw, an inability to handle compressed music and music with intentional distortion, e.g. arcade fire, sonic youth, flaming lips, spoon, tame impala.
there is an additive distortion effect to this music that makes it intolerable to my ears. tube amps handle it ok, class ab a little worse but class d not happening.

This is the heart of the problem with Class D, in a nutshell.

100% of the music, for the human ear, lies in the proper placement and expression of micro detail, in time, in living breathing relation to all bits of said micro detail, in time and levels (micro and macro levels in micro and macro time..)(the ear/brain is the world's finest FFT system and varies in quality and effectiveness from person to person)

This is the part that Digital and Class D get wrong. It’s intrinsic to the technology of both. Core.

Their ’residual’ distortions are right in the heart of how the human ear/brain functions and listens. 100% of how the ear/brain works, is squarely in the sights of how and where in the signal -that these technologies distort.

Therefore, to the discerning ear and mind, both are a failure.

Listenable? Sure. For some of us, if we grunt and ignore our natural tendencies in how we listen.

Best? Very much a no.

I’ve said this, now, maybe a good few dozen times on this forum and human ignorance and projections says I’ll probably have to say it forever. That it will outlast me and wear me down. Where this norm of the human condition really will manage to eventually...cut down trees with herrings. Forever. Until humans evolve into something else with a different set of cognitive problems. Plenty more where that came from...
Therefore, to the discerning ear and mind, both are a failure.

well, there you have it

calling junk pros now...
Hey..., they may please some, but not others.

eg, define 'discerning ear'. What does that mean as a word paring - in a high end audio context?

The complexity of the simple statement, when unraveled, is, well, maybe a hair more explicit and detailed.

Declarations of perfection, if they occur.. will be shot down with a proper extreme prejudice. At least that’s what I may chose to do in the given moment. Tomorrow I may not care and today I might care.

Same for you, I might expect.

I might come to your abode, grift you out of the amp.. while posed as a junk collector... and then sell it to the folks who want it. Aafter listening to it, of course. After I listened to it, my opinion certainly would not be definitive. That would unwell projection.
I have 4 different Class D amps running in my house. They all sound dam good. Not to mention good value. As good as most anything in each’s class if not better. I have 4 because I started with one and went from there and have not looked back since. If Class D had not worked out for me I was ready to explore tube amps. Didn’t need. Class D is like the best of SS and tube amplification in one. It’s different. So no reason to expect everyone to love it just like everything else. But personally I think it is the way to go these days and will be even more so as time goes on. I have heard the Anthem but not the NAD. It sounded very good driving Klipsch Heresy IV, the best Heresy sound I have heard to date. Lots of technology in these new amps beyond merely Class D amplification. It’s a whole new world. Some will go there others not. Count me in! I will need another new amp sometime I expect.
I also find the NAD Class D I have a little lean, however, as I said, this is a tonal issue.  I find the ICEpower the opposite.

I have _exactly_ the same problem with A and A/B amps today.

I'm not saying you should not criticize Class D amps, but rather, criticize them for how they behave today, in the 21st century, not how they did in the 1980s.


Class D have come along way but they still dont quite measure up. With the right speakers, nothing equals tube and no tube design equals OTLs.

Class D as commonly done today and OTL are apples/oranges at least technically and in terms of the system they might be used in to sound best. Class D will work well in place of OTL technically but likely still not sound the same. OTL has no chance of replacing Class D categorically.

So realistically you can compare the two and favor one over another but absolute statements in regards to superiority are probably subject to challenge at best.

Now I understand Atmasphere is working on a Class D amp. That would be interesting to see what he comes up with and how it compares both to other Class D amps and his own OTL amps.
Check out John Darko’s YouTube on NAD.  He’s not the only one who thinks NAD has had a breakthrough on Class D so it’s finally competitive.

but if you want GREAT sound,  get a pair of Schiit Aegir monoblocks.  Nothing anywhere near the price comes closely.

And they heat your house in winter!
If it’s OK for you, it’s OK with me, but not FOR me. Class D is everywhere and will continue to coexist with the rest of the alphabet. I have some old Emotiva Class D amps in my surround sound system. When I use the room-EQ gadgets on my surround pre-amp, movies, TV and concerts sound pretty darn good--even on YouTube. But there’s a reason why I have another set of electronics for stereo music and critical listening.
It all opens up the question of ’reference’. What is it? Especially for audible art that has been frozen in time by various recording methods? Whatever we listen to, the original sound lasted no more than a few seconds. Yet it’s the only reliable reference I know--live acoustic performance. Let’s admit there’s no reference at all for most of the mediated sound we hear every day. It’s mostly digitized, time-shifted and duplicated to the point that even watching ’live TV’ is really an illusion. The signal has gone through so much electronics that time becomes fungible. Hopefully, a Time Bank will eventually allow us to save, borrow and spend Time as we wish. Just let’s all be careful to maintain some sort of phase integrity!
but if you want GREAT sound,  get a pair of Schiit Aegir monoblocks.  Nothing anywhere near the price comes closely.

This is so so correct and almost on the money, except  do the Aegirs bi-amped horizontal (not bridged) as all bridging gives you is more watts everything else that makes for a good amp suffers.

Cheer George
Schitt Aegir looks pretty good for a 20 w amp if that’s all one needs.
When/if THX AAA technology becomes proliferated, class D will be rendered obsolete outside of portable and automotive applications. 
As the owner of the Purifi Audi amp modules and the Starke Sound AD4.320 (on sale at a ridiculous price - under $900 - Blsck Friday and all that - I'm ordering another one today) this new approach to Class D these two companies are using will reorganize your mind. The switching rates are so high that any effects in the audio band are non-existent. The sound of these units is the best I've ever heard. Period. These are the truly "transparent amps" at last. Don't spend a nickel on a power amp until you have heard one of these.
Yes I know Ralph is working on a Class D amp and thinks the design holds promise. Yes I agree with what you said about comparisons. Just my 2 cents not prefaced with IMO. 

I have NAD C370 after 20 years the protection circuit took a bit to much time to switch the amp on. So i bought for 2,75 Euro replacing condensators an turned the Zener Diode which causes the problems an it was done.

Problem what i read about modern class D amps (I'am quite impressed by Hypex amp’s) they are making use of lost of micro switches fast switching power supplies an specific none uploadeble eprom code. Because of that Life span is expected between only 5 a 10 years. I rather do an proper restoration on my 20 year old excellent sounding NAD for less than 3 a 400 Euro an enjoy it for 20 years or more or longer because replacing parts have a way better life span because they are able to work under higher temperatures conditions compared to the old elco’s an condensators.

I guess I am an audio snob because I would never consider a NAD component in any system I have.  I don’t care if it class A,B,D or whatever.  I have the same feeling about Rotel and other less expensive brands.   If I was just starting out, perhaps I would feel different. 
I am willing to bet that a year from now, there will be many NAD 33’s for sale because the next latest and supposedly greatest have come to fruition. 
i have felt the same way about NAD since 35 years ago i had the 3020 as my integrated while being a student driving ls3/5a’s... nad being good solid budget hi fi but really cannot compare to the true big boys

in more recent years they tried to make the move into higher priced categories with their m (’masters’) series gear... unfortunately they went class d for their amp sections in this series and the implementation was poor (like many others) and the sound was lifeless grey and bleached out -- just sub par for a line they hoped would compete with higher brands... still they sold many units with their (relatively) value oriented pricing, and they built in many functions into their units like dacs and dirac room correction - nonetheless the sound was poor compared to who they were competing against, for those who actually compared critically

this m33 with the purifi module is supposed to change this... at this point there are many decent reviewers confirming the sound is much improved, finally on par with the best class d implementations out there

value oriented buying decisions in high end hifi obviously happens at a variety of different spending levels... nad is certainly appealing to some of them...
The mini, book sized integrateds are also very nice for desktop or bedroom use. Look at the 3020D for instance. It would be very interesting to know if those hybrid Class D modules were brought over.

The issue I've had with modern NAD was not the amps, but the DAC's, which while not top tier per se, have greatly improved since the Masters series first came out.
Not having my present system, I surely would be looking for an all in one integrated like the Nad M33. Would also be considering the Micromega M-150, and Devialet or Hegel. Linn and Naim also have very nice alike products.

Advances in dac technology have made these very near sota. No need for multiples boxes anymore. This is great, takes less space, cost a lot less in interconnects and power cables, etc.
Honestly the proof is in the listening. I’ve not heard these integrateds, and I have been burned more than once by reading a series of glowing reviews for a product only to be completely let down after listening in person, but based on my listening of the prior, small integrateds I think they are worth it.

Here's what I am convinced of:  They don't sound like 1980s digital amps.  As we've seen, above, lots of people don't want to hear anything but their flavor of tube, and I can assure you Class D does not sound like them either. :)


This thread has jogged my memory, as it seems I've actually auditioned several Class D integrateds -- the Devialet, the NuPrime and the Lingdorf.  Of the three, the Devialet came closest to pushing my buttons but none of them got me to replace my PrimaLuna.

     Ah, fun with FFTs.  Teo_audio's posts can be relied upon to be interesting and very cerebral as he explores the core of subjects from unexpected directions.  Excellent work and please keep 'em coming.
     I've read and participated in numerous dialectics about class D amps ever since these amps began to be very good about a decade ago. It's weird, but just in the way it's something to note, that the reactions to and discussions about class D amps haven't progressed much beyond the apparent conclusion that many, including myself, love them and that many do not for various reasons. 
     l find it confusing and confounding, however, how I can perceive the performance of many of the class D amps I've owned or listened to as being exceptionally good while many others perceive sound quality deficiencies with class D amps, or at least claim they do. 
     My suspicions of these supposed class D sound quality deficiencies, and even the motives of the claimants, stem not only from their complete and consistent lack of any proven scientific supporting evidence but also from my personal complete and consistent failure at perceiving any of these supposed sq deficiencies they've described during the past 6+ years of my owning and using 3 different brands of class D amps and listening to many more.
     There's been a serious dichotomy of opinions on the performance quality of class D amps over the past decade or so.   I've chosen not to be overly concerned about these opposing opinions since I perceive my class D monoblocks as performing spectacularly well in my system and I don't perceive any of the claimed sound quality deficiencies perceived and described by some others, which means by definition that these alleged sonic deficiencies don't even exist according to my perceptual reality.  Perhaps I'm just lucky for not being able to perceive them or perhaps these supposed deficiencies actually don't even exist. 
     Which is it?  I'm not sure but I think it's best that I keep an open mind.  I believe it's possible, if not likely, that future scientific evidence may emerge that identifies and proves that class D sq deficiencies actually do exist but that only a minority of individuals have the ability to perceive them.  There are no guarantees, of course, but it would explain this dichotomy of opinions rather nicely and neatly.
     The other subject I've noticed a serious dichotomy of opinions on is the big, fat, orange, dopey guy. This recent and very important election, about the performance quality of our President along with the fate of our nation and democracy, I can't avoid being overly concerned about since I, and about 80 million fellow citizens, perceived him as a collection of the worst human personality traits along with the leading candidate for the worst President in the history of our country. 
     The fact ,that about 70 million of my fellow citizens actually voted for 4 more years of this disaster of a man and Presidency however, also greatly concerns me.  Unfortunately, I can only rationalize this mass attraction to such a poor excuse for a human being by realizing that Trump happens, the attraction likely representing more of a protest or symptom of underlying problems as much as anything else, such as an entire group of hardworking, middle class and patriotic citizens perceiving their relatively inequitable conditions and treatment as well as being politically ignored for far too long.  But that's a worthy discussion probably best had on another forum.
     Anyhoo, I believe the opinions on both class D amps and Trump will remain characteristically contesteous, combative and dichotomous for the foreseeable future.  Only when all future developments, histories and facts about each can be fully known and scrutinized from the clear, accurate, honest and complete perspective of retrospection, which may  require 100 years or more.will the full story be known about each subject.
class d is a generic labeling of amplifier type

just like there are good and bad tube amps, class a/b solid state amps, mosfet amps, bipolar transistor amps, nos r2r dacs, moving coil cartridges, belt drive turntables, ribbon tweeters, electrostats... it is all in the holistic implementation of any particular offering that matters...

class d amps as a class, over their development in the past decade plus, were touted as the next best thing... yet many early versions did clearly sound poor... thus the reputation/hearsay came to be

just like digital, progress continues and improvements are made and those with open minds are wise to revisit past beliefs, which may have been perfectly reasonable and accurate at the time...
Jjss49..........well said 
+2 jjss49

     You gave a good summary, seem to have a good grasp of the subject and true dat.

Post removed 
The best experience I’ve had with class D was with a low powered unit by SPEC.  I’m curious if Atmosphere is familiar with their amps.  In the end I found I was listening less, so it got the axe.  I’ll be skeptical of class D after that sham of a thread where everyone was selling $40k worth of tube gear to buy a particular class d European amp.  That got the axe much quicker than the spec. Hope you all enjoy what you have to be grateful for. 
Here's what I am convinced of: They don't sound like 1980s digital amps.
This is a fact, though, the word “digital” is a misnomer when used to describe class D. More appropriate to refer to them as PWM is it not?

The topology has improved vastly, even in just the last 10 years, and the good ones are at least listenable. I can certainly tolerate their use in cars and Bluetooth speakers at least.

happy thanksgiving to you and to all

you are right... i would say that anyone posting on this forum has a lot to be thankful for
Genelec 8351B uses Class D amps. Sounds more than good enough to me. Those speakers are harder to beat at 10 times the price. 
NAD 33. Decent but not a Simaudio ACE or NAIM Uniti. Same money or less, much better sound 

NAD 33. Decent but not a Simaudio ACE or NAIM Uniti. Same money or less, much better sound

have you tested side by side under controlled conditions?  not debating your statement - just wondering what it is based on...