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
Several of you are leaning toward NAD.  I had a 2200 PE or something like that, 100 wpc.  I liked that it was very clean sound, with no tonal imbalances.  I did not like all of the instruments and voices coming from the exact same place, making it sound like one very fine synthesizer.  I expect the same, or worse from their Class D amps, but here's hoping for the best?  Someone is bound to figure it out, if they have not already.  Those who refuse to even listen will die off, as will I, with my beloved Audire equipment.
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.
@erik_squires

The reason it’s a mediocre implementation would be obvious if you (or really anybody here) had bothered to read detailed measurements of other PuriFi implementations, which routinely reach -120db SINAD. The fact that NADs implementation is around -92db is pathetic by comparison. 

No axe to grind, just facts..
Being in the business of building audio components, I wish that we could build one as good as our power amps but so far we have not been able to.  That being said, I find that systems that use class D amplification generally use another component in the system that seems to try to compensate for the Class D sound such as a tube preamp, etc.  Our main challenge is that we prefer tubes for sound they produce which is the dimension of the sound stage, decay of notes especially piano, etc.  I am not saying that there is no benefit at all, but our opinion is that we just do not prefer the sound in comparison.

Happy Listening. 
The reason it’s a mediocre implementation would be obvious if you (or really anybody here) had bothered to read detailed measurements of other PuriFi implementations, which routinely reach -120db SINAD.


That's why it's nice to put supporting evidence or points in your post at the time you throw shade. It's far to easy to misinterpret any particular reason why you felt this was mediocre, or to be unable to seek out possible disagreements in the interpretation.

The actual specifications  are:

  • Signal-to-Noise ratio
  • >98 dB (A-weighted, ref. 1 W out in 8 ohms)
    >120 dB (A-weighted, ref. 200 W out in 8 ohms)

  • So, you are incorrect, by 6 dB ( a lot) at 1 watt and please be sure you are measuring apples to apples and using the correct power spec for the S/N.  If not specified, assume it's at full power.

    I strongly suspect your 120 dB comparison was at full power.  Let me know if you find a reference to data that shows my interpretations are mistaken.



    Best,

    Erik