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NAD M33 Streaming Amplifier Review

Descartes

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This is a review and detailed measurements of the NAD M33 Streaming Player with Purifi Eigentakt Amplification. It is kindly sent for testing from a member and has a retail cost of US $4,999.

The NAD is part of their "Masters" series and has one of the best industrial designs of any audio gear I have seen:

View attachment 91653

It is both modern and luxurious. The touchscreen is not as fast and accurate as your phone or tablet but ages ahead of many other displays on audio gear. On the other hand, as I have noted before, I hate the touch power button on top which seemingly requires multiple touches to actually turn the unit off.

Notice the cool instrumentation panel telling you the internal temperatures. Then again the unit runs so cool that such monitor is not needed in practice.

The back panel shows decent connectivity although I was very disappointed to not see balanced XLR pre-out:

View attachment 91654

There is balanced input but why not output?

Dirac Room EQ is provided putting it on par with home theater AVRs in that regard but obviously for only two channels.

I was pleased to see network firmware update work and work a lot faster than a lot of AVRs and processors. It indicates a clean architecture than a boatload of licensed chunks/subsystems each of which has its own kludgy update mechanism (I am talking to you Arcam).

No USB DAC functionality is provided which is a big miss. And Roon endpoint lacks certification which means it is useless with newer versions of Roon that I have. Roon now refuses to use these uncertified implementations. Strange to see a company the size of NAD has not finished the certification. Ariplay streaming works but it limits streaming to 16 bits.

NAD M33 DAC Measurements
As usual we start with our dashboard of feeding the unit digital content and measuring what analog output we have out of the pre-out. First measurement was disappointing:

View attachment 91657

Distortion was extremely low but that rise in low frequency noise was not something I had seen. I then realized the amps were on so I turned them off and performance much improved:

View attachment 91658

This is much better performance than we typically see in this class of product. Comparing it to AVRs and AV Processors for example, the M33 is way above the class:

View attachment 91661

Whoever said you can't combine EQ and DACs and get good performance was just proven wrong!

Output can go up to 4 volts so let's measure the full response range:
View attachment 91666

Nice! You have a broad range of usability up to 3.2 volts.

Dynamic range is very good as well:
View attachment 91664

Linearity is nailed:

View attachment 91667

Jitter over Coax input is problematic from measurement point of view but not audibility:

View attachment 91668

Since jitter amplitude is frequency dependent (gets worse the higher the frequency is), it actually pollutes the higher frequency tones in multitone:

View attachment 91669

Otherwise performance is very good.

IMD distortion relative to level is excellent sans our famous "ESS DAC IMD Hump:"

View attachment 91672

Fascinating that small companies in China have solved this problem yet a major company like NAD has not. Shame on ESS for not providing a solution for all of their OEMs to benefit.

Reconstruction filter could be better:

View attachment 91673

This impacts the default measurement of THD+N versus frequency due to allowance for more ultrasonic noise:

View attachment 91674

NAD M33 Amplifier Measurement
The Purifi amplifier used in NAD is one of our favorite, top performing class D amps. My previous review of the NAD M28 Amplifier showed that NAD had compromised performance some, likely in their buffer stage. Let's see how the M33 performs using analog input first:

View attachment 91675

Ah, looks like we take another hit again with a SINAD of 93 dB versus 98 dB for M28 which is a shame. Looking at the frequency response however shows that the analog input is digitized first and then converted back to analog for amplification:

View attachment 91676

The pass to and from digital domain adds distortion and noise so degrades performance some. Let's use digital input then and eliminate the effect of the ADC:

View attachment 91677

We have good and bad news here. Good news is that the ADC is essentially transparent which is a first in any digital device/AVR/AVP. Bad news is that eliminating it didn't get us much. So for the rest of the tests I will be using analog input for easy of measurements. The ranking is still very good though:

View attachment 91678

And comparison to AVRs:

View attachment 91679

Likely the amplifier is as good as what is in M28. It is just that we don't have a transparent path to it. The above AVRs were mostly measured with digital path to the amplifier so a bit unfair. Still the M33 outperforms them all.

I love to see 16 bits of dynamic range at 5 watt output but rarely see it. The M33 delivers on that which is great:
View attachment 91681

Crosstalk is excellent and near state of the art:
View attachment 91684

Let's see the power into 4 ohm:

View attachment 91685

Ah, this is not as impressive as I was expecting especially in the one channel. Lots of power is available though at 421 watts.

I could not get burst performance because the amp's protection would kick in. But here is the power at 1% THD:
View attachment 91686

Same into 8 ohm:

View attachment 91687

Let's switch to digital input to see if there is improvement:
View attachment 91688

We are doing much better than AVRs but the channel inconsistency is still there.

Finally let's test for frequency dependency:

View attachment 91689

If you took away the writing on this graph I would tell you this is a measurement of class AB amp, not switching class D! Most class D amps have all kinds of strange non-linearities but not this Purifi amp. There is no change in response with power and only modest increase in distortion with frequency. The clean heart of Purifi still beats inside the NAD M33!

NAD M33 Streaming DAC Measurements
As I noted in the intro, I was out of business streaming lossless 24 bit test signals I need for our dashboard. Roon would refuse to talk to it putting up a "shame you NAD" dialog box. So I resorted to Airplay which due to conversion to 16 bit has a limit of 93 dB SINAD:

View attachment 91694

So we are as good as the transport allows.

Conclusions
There is a lot of good news and some bad news in review of NAD M33. As an integrated product it shows for the first time that quality does not need to be compromised. Performance across the board beats any integrated product like an AVR or even AV Processor on DAC performance. For the first time, we don't have to apologize or make excuses.

If you were however expecting the pure performance of best in class stereo DAC and Purifi amplification you would be disappointed. We can get SINAD of 120 dB in desktop DACs and Purifi performance of 98 dB. And at much lower prices but you would have add a streamer of sorts. And none will have the pretty UI of the NAD M33. And you would have to find one where you can use Dirac (e.g. a PC platform).

As compared to an AVR, the M33 is a home run albeit at much higher price and with just two channels.

All in all, NAD shows the path to superb performance in integrated products. It however stops a bit short of what it could be.

Overall, I am happy to recommend the NAD M33. Just miss the bit of performance it left on the table.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Planted a bunch of watermelon and cantaloupe against my better judgement as we just don't have enough sunny days for them to fully develop. Still, the plants did their best producing these cute little melons:

View attachment 91697

Alas, inside was mostly white and barely sweet. I have a much larger one to test so hoping that one will be better.

Appreciate any kind donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I am trying out an NAD M33 and was wondering if I should use analog out from my CD player to the NAD or should I use coaxial cables? Also I have an older OPPO BDP-105 should I use the HDMi cable or the analog connections? It is just to listen to music
 

pogo

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The digital versions are always preferable.
Is the M33 equipped with an HDM2 or how else do you want to connect the Oppo?
 

Descartes

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The Elysian hardly need more power than what M33 can master at 92dB 8 Ohms sensitivity. However, I'm sure there will be some improvement in sound quality with M23 in the system. My cunning plan is to start using those two boxes and then replace M33 with M66 later this year, with the missus not noticing anything sus after the upgrade! Bi-amping require an additional pair of expensive speaker cables and I'd rather not purchase it if bridging is the better way.
No need for expensive speaker cables just a good pair of mogami or canaree cables will sound perfectly good!
 

Descartes

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The digital versions are always preferable.
Is the M33 equipped with an HDM2 or how else do you want to connect the Oppo?
Thank you for the swift reply, why is that?
So coaxial cables then, but Amir shows jitter in the coaxial cables.
How about optical cables?
 

pogo

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You can also try the optical input, but this should not make an audible difference. Going from a digital source analog into the M33 makes no sense, as an additional DA/AD conversion is added.
 

Descartes

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You can also try the optical input, but this should not make an audible difference. Going from a digital source analog into the M33 makes no sense, as an additional DA/AD conversion is added.
Fair enough, having multiple digital to analog conversion just muddy the waters, might as well stay in the digital domain until the signal is sent to the speakers!
 

Descartes

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Ok so using coaxial cables won’t play any of my SACDs?
Anyone please help, what am
I missing?
I find the BlueNote remote useless!
 

pogo

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The Oppo manual describes why this does not work. You can only send DSD to PCM converted signals to the M33 via the HDMI output.
Have you installed an HDM-2 or are you using the HDMI ARC on the TV?
What is the problem with the remote?
 

Kal Rubinson

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Ok so using coaxial cables won’t play any of my SACDs?
Anyone please help, what am
I missing?
I find the BlueNote remote useless!
The M33 (and, I think, all BluSound devices) will not play DSD. Must convert to PCM.
 

Descartes

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The Oppo manual describes why this does not work. You can only send DSD to PCM converted signals to the M33 via the HDMI output.
Have you installed an HDM-2 or are you using the HDMI ARC on the TV?
What is the problem with the remote?
Using the HDMi ARC!
 

Descartes

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It still won’t work with SACD disc with DSD unlike the Anthem AVM90 that actually takes DSD!
 
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