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.
erik_squires
@anotherbob 

I certainly hope so, if any rube on the internet can order up PuriFi or nCore parts and put them in a ChiFi case from eBay, achieving superior results, surely a company with NADs resources can too... 


Or maybe not?
My understanding is that NAD is not using the 1ET400AEIGENTAKT module but building one very similar, with some kind of licensing agreement.  Why they went this route I don't know--several possible explanations present themselves.  I too am hoping for a 2-channel power amp in the Masters series.
I was deciding for a few months between the Hegel H390 and NAD M33 for my B&W 802D2 speakers. My dealer sells both the Hegel H390 and NAD M33 (and also NAIM, Devialet, and Linn) and had both in stock and told me after several long listening sessions with the new NAD M33 that they both are great but he preferred the NAD because of how clear, detailed, and dynamic it was, the great stereo imaging, strong bass, and beautiful mid range and just the overall musicality of the NAD.

Based on my dealer’s recommendation I bought the NAD M33 but he also said if I was not happy with it I could trade it back in and swap it for the Hegel H390 for 100% credit of the amount that I paid. I have had the NAD M33 now for 5 weeks and love the sound of it and have no plans to swap it out for the Hegel H390 or anything else for that matter. I don’t use Roon but with the bluesound operating system and Spotify connect and the now newly released Tidal connect on the NAD M33 the flexibility and ease of use of the NAD far surpasses the Hegel H390.
seanheis1:
" Here is a quote from Bruno Putzey, creator of Hypex modules and Mola Mola in an interview with Sound & Vision.

S&V: Generally speaking, what are the key benefits of Class D versus the traditional Class AB and Class A designs that have long been favored by audiophiles?

BP: Efficiency and therefore the ability to construct amps that are powerful for their size. Only that. Modern Class D amps, in particular mine—ahem—sound good not because they’re Class D, but in spite of it. I can’t repeat that often enough. Left to its own devices, a switching power stage tries to do just about anything except amplify audio. You choose Class D to save energy but it’s all elbow grease after that. People don’t realize how much more challenging Class D is compared to Class AB. It’s truly an order of magnitude."

Hello seanheis1.

I read that full Sound & Vision Bruno Putzeys interview years ago. I noticed you selectively cited only the above quote from BP from the interview because it, apparently, supported your own opinion on class D but failed to cite other quotes that do not. I believe it’s useful for anyone on this thread or anyone interested in class D in general to read the entire interview, less your selective censorship and cherry picking of quotes, to obtain a better understanding of class D and BP’s unrestricted thoughts on the subject. To promote the honest, full and accurate edification of thread readers and continue this free and open discussion of the pros and cons of class D amplification, here’s a link to the complete Sound & Vision interview:

https://www.soundandvision.com/content/bruno-putzeys-head-class-d-page-2

For those readers lacking the time to read the entire interview, here are a few other interesting and relevant BP quotes from the interview seanheis1 conveniently felt the need to omit:

"S&V: Conventional wisdom says a great amplifier has no sonic character of its own and, beyond boosting the signal level, is transparent in the audio chain. But does the nature of high-quality Class D amplification—perhaps through the absence of distortions found in other circuit topologies—produce a particular sonic signature or specific attributes you could describe?

BP: Well, if the amplifier is truly great that’s absolutely right. Sonic signatures are what you get when you approach the same ideal from different angles. There are a few distortion mechanisms conspicuously missing in Class D, mostly those related to the input stage of a Class A(B) solid-state amplifier and nonlinear capacitances. Those are also missing in valve [tube] amplifiers so it’s quite common for people to notice that a Class D amplifier is somehow reminiscent of valve amplification in terms of “sweetness” for want of a better word.

I’ve heard several reports of valve aficionados ditching their glassware and switching to Ncore. All I can conclude from that is that those people clearly weren’t actively seeking the distortion of valves as many believe, but instead had a legitimate beef with certain sonic aspects common to most solid-state designs. That’s one thing I have to explain again and again to my fellow doubters: when audiophiles report a particular listening experience, that experience is real. Trust that. Just don’t trust the explanation they proffer.

S&V: The new generation of Class D amps are obviously good enough to herald audiophile kudos, as we saw most recently with David Vaughn’s review of ATI’s AT527NC and AT524NC amplifiers, but what lingering issues might still need to be resolved to move performance to an even higher level?

BP: I’d say that basically the cat has been skinned. Further refinements will surely happen but the same can be said of the other amplifier classes. In terms of things affecting sound, I don’t see any fundamental outstanding issues that merit much attention—it’s mostly down to lesser implementation details, ordinary technological progress, and perhaps some more adjustments in the math department. I would like to see magnetic materials with less hysteresis though."

The complete interview contains a lot of other interesting and relevant information about class D, I encourage anyone wanting more unadulterated information on class D to read the full interview.

Tim


     Sorry, I just noticed my link to the complete Sound & Vision Bruno Putzeys interview began on page 2.  Here's the corrected link that begins properly on page 1.

Oops, I apologize,
  Tim
https://www.soundandvision.com/content/bruno-putzeys-head-class-d