NAD M33 Integrated Amplifier Reviewed

The NAD M33 (buy at Crutchfield) is so much more than an integrated amplifier that it’s a shame that we have it listed in our audiophile amplifier category. Unfortunately, we don’t have a Swiss Army Knife of Audio Components category or even a just-add-speakers section. But before you begin to worry that NAD simply packed a box full of features to please someone in Marketing, this is part of the NAD Masters series, which is the company’s higher end gear, and even if it weren’t so, when have you known NAD to put flash before substance? 

The NAD M33 is a stereo preamp, class-D power amp, streaming device, and audiophile digital-to-analog converter built into one chassis, with room correction to boot, for a retail price of just under $5,000. One one hand, that’s a lot of money. On the other hand, when you consider all that you’re getting in one product, the NAD M33 could be considered quite a value. It just depends on your outlook. Can an all-in-one box be the solution for your high-end audio needs, though? We now know our mission here, so let’s dig into it. 

What Makes the NAD M33 Integrated Amp Special?

• The NAD M33 does just about everything under the sun. It is a preamplifier, amplifier, streamer, DAC, features room correction, and is multi-zone capable all in one chassis. On that note, the chassis is an attractive, two-tone aluminum box that should be at home in any high-end audio system. The main body is brushed silver with black accent panels. The front panel is dominated by a large touchscreen set into a black aluminum panel. The screen is flanked by a power button styled as an NAD logo on the left and a large volume knob on the right. Just underneath the black panel, below the NAD logo power indication button, is the headphone output. The top panel of the M33 also caught my attention, in a good way. It has eight, large, rectangular vents that have a black mesh material in the middle and another black aluminum plate above the silver-colored chassis for an attractive, two-tone riff on what is normally a boring but functional vent design on most components we review. This is a great-looking chassis.
• The attractive chassis houses a powerful HybridDigital Purifi Eigentakt amplifier that delivers a continuous 200 watts per channel into 8 ohms and 380 watts into 4 ohms. The amplifier is bridgeable to a whopping 700 watts into eight ohms, and a bridged NAD M23 stereo power amp can power the second channel if you go this route. The amplification alone in this gorgeous chassis would not be out of place at this price point, but NAD manages to pack many more features into this relatively light 21.4-pound component. 
• The other main function of an integrated amplifier is to perform preamplifier functionality: switching between sources and adjusting volume. The M33 has one each single-ended line level, balanced, and MM/MC phono inputs. On the digital side, it has a pair each of coax and optical inputs, one AES/EBU, and an HDMI eARC. There is also a USB port that you can connect to a storage device, which is a welcomed feature. Digital inputs are all 24-bit/192 kHz and MQA capable via BluOS. On the output side, there are two sets of five-way binding posts, a pair of single-ended subwoofer and pre-amplifier outputs, and of course the previously mentioned headphone jack. In addition to the audio connections, there are IR trigger, 12-volt trigger, service ports, RS-232, and an Ethernet port. I know, it’s a lot of connections for a two-channel pre-amplifier. We’re not done yet. As they say on those TV infomercials: “But wait, there’s more!” 
• If the physical connectivity weren’t enough, the M33 also has Bluetooth and Wi-Fi. It’s also Roon Ready and AirPlay 2 compatible. You can use the aptX HD capable Bluetooth connection to transmit to the M33 from your smart phone or from the M33 to headphones or Bluetooth speakers, but I suspect if you’re transmitting to other speakers, you would probably want to use the built-in BluOS streaming platform. Greg Handy discusses the BluOS platform in more detail in his review of the NAD C 700 here, but in brief, think of BluOS as a multi-zone streaming system that places a priority on audio quality and, utilizing an easy to us app, can integrate the M33 with numerous streaming services and playback devices. The BluOS ecosystem also includes standalone streamers and wireless speakers, such as the Bluesound Pulse Mini 2i, which the company was kind enough to send out for me to try with the M33.
• The M33 comes with limited-bandwidth Dirac built-in as part of the purchase price. There are five memory slots, so you can easily try different settings to see which you prefer or even keep multiple music settings for different music, listeners, etc. You can upgrade to full-frequency Dirac if you want, but, in many cases, it is the included lower frequency range that benefits the most from room correction systems such as Dirac. I would try Dirac as it comes before investing the money to upgrade to the full-bandwidth version.
• The NAD M33 employs ESS’s highly regarded 9028 Sabre DAC chip. 
• I spoke favorably about the M33’s build quality from a design viewpoint, but there is another, even better feature that can greatly extend the M33’s lifespan. It utilizes NAD’s Modular Design Construction (“MDC”), which is a system that allows for card-like modules to be inserted in the back panel, adding ports or other functionality. The NAD M33 has two MDC ports, providing plenty of room for future expansion.
• The parts of the M33 that you actually touch are really nicely executed. The volume knob feels super-smooth and significantly weighted. The remote is a custom unit with a metal body that has substance but provides plenty of functionality in a world where most remotes kinda suck. Other little touches include iso-point feet that are magnetic to keep their protective discs from falling off when setting the M33 into place.

Why Should You Care About the NAD M33 Integrated Amplifier?

The M33 and a serious pair of audiophile speakers are all you need for a high performance, somewhat-future-proof audiophile system. Yes, you could add your favorite analog source (think: a heavy duty audiophile turntable) but if you are tight on space or if the NAD M33 is a financial stretch and does not leave sufficient funds for the source you have your eye on, the built-in streaming provided by the BluOS system along with the Bluetooth and AirPlay 2 functionality should let you listen to all your favorite digital music. 

Some Things You Might Not Like About the NAD M33 Integrated Amplifier

• There are no balanced outputs for either the subwoofers or preamplifier output in the event that you want to grow your system with even fancier external audiophile amps. 
• The NAD M33 digitizes incoming analog signals. While the ADC-to-DAC chain is transparent-sounding to my ears, there will be some audiophiles who want the option of potentially bypassing digitization. On a related point, there is no Home Theater Bypass to ease integration into a multichannel AV system. 
• The Dirac implementation includes five presets, which is pretty sweet, and you can upgrade to full range filtering, but Dirac Live Bass Control (“DLBC”) is not an available option but we’ve been told is coming soon. I personally have not had an opportunity to experiment with DLBC, but some of my industry colleagues speak highly of its abilities to maximize performance with multiple subwoofers. On the other hand, if you are not running subwoofers, this will not make any difference in your implementation. 

Listening to the NAD M33…

I used the NAD M33 in a couple of different systems in my house, but most of my listening was done with my Revel F328Be speakers connected. I added a pair of SVS PB-4000 subwoofers later, when I was experimenting with the Dirac implementation. Having multiple Dirac presets made it easy to test out different settings.

My teenaged son and I had been playing a lot of classic rock when the NAD came in, so one of the first tracks I listened to was Led Zeppelin’s “The Battle of Evermore” from Led Zeppelin IV streamed through Tidal. While I love the music, it is not one of my go-to tracks for reviews. I found it to be a little thin and on the bright side, but this was promising for the NAD M33 as it showed me that it was playing the audio file without adding anything to it. I do not want my audio gear changing the sound of the music. There are more gleamingly awesome tracks to hear, but it is nice to know what you are getting with the NAD M33: no coloration. 

Moving to another Led Zeppelin song, “Kashmir,” I listened to the much updated and audiophile demo approved version performed by Marcin. If you are a fan of creative and modern guitar, give Marcin a listen. Not only is the performance great, but the sound quality is also quite good as well, with a palpable, dynamic texture. The guitar is full-bodied with weighty bass while remaining clean and detailed enough to really appreciate Marcin’s mastery of the guitar when playing it back on the NAD M33. 

Moving to Dominique Fil-Aimé’s “Rise”, also streamed via Tidal, I started playing with the NAD M33’s Dirac implementation. I ran through the Dirac setup process. Once that was done, I continued my listening without Dirac before switching it on. The M33 did a spectacular job placing the vocals front and center just slightly behind the plane of the speakers’ baffles with the instruments slightly farther back. This track prominently features Dominique’s vocals, with the instruments taking a backing role. The ethereal and nuanced qualities of the vocal track are well reproduced. Switching the Dirac processing in, the biggest differences were the tightening of the bass guitar and deepening of the soundstage. 

Our last track is another female performer but a totally different genre. Taylor Swift’s “Vigilante Shit” also features vocals prominently, but adds a bass-heavy and synthesized backing track. This makes any discussion of natural reproduction of instruments meaningless, but provided a good way to check out the NAD’s bass capabilities. While the Revel F328Be speakers (read the review) are not the last word in deep and powerful bass in the world of roughly $20,000-per-pair audiophile speakers, they are very clean and quite respectable in the low end, even without a big-time subwoofer in the loop. 

The M33 kept the speakers’ bass notes taut and well defined but I had heard this track on speakers with a more robust bottom end and could tell something was missing. I then added the pair of SVS PB-4000 subwoofers and re-ran the Dirac setup process and saved my results in one of the blank presets. With a little bit of fiddling, I was able to get a smooth transition between the Revels and the SVS subwoofers, which provided significant extension and power on the bottom end. If you want to run subwoofers with your main speakers, the Dirac-enabled M33 makes it easy to do so with good results. The only qualm I had about the subwoofer implementation was the lack of balanced outputs, as I already had balanced cables run to my subwoofers. 

We also listened to some vinyl using the Pro-ject Debut Carbon Evo ($599 buy at Crutchfield). The M33’s phono stage did a good job by maintaining dynamics without adding any noise. I tried the headphone output with the Cleer Audio Next (read the review) and Mr. Speakers Aeon Flow and found it to come close to the standalone headphone amplifiers but with a touch less resolution and authority. 

Lastly, NAD was kind enough to send me a Bluesound’s Pulse Mini2 ($549 buy at Crutchfield) wireless speaker. The mid-sized speaker measures 13-3/8 inches wide, 6-7/8 inches high, and 6-1/8 inches deep and comes in black or white. Our review sample was an unobtrusive matte black with a small gloss black control panel on the top. The Pulse Mini2 has Bluetooth and Airplay 2 connectivity, but what made it special is the BluOS operating system, which let me integrate it with the M33 and play music from the M33 if I so chose to do so. It could also be operated independently. The BluOS ecosystem operated simply and without any hiccups. 

Does the NAD M33 Integrated Amplifier Have Any Resale Value?

Yes, the NAD M33 sure will retain resale value over time. Digital audio tends to get outdated quickly, and like video capable gear will not hold its value as much as speakers or amplifiers, but NAD’s MDC architecture will allow for updates to keep the M33 in service for years to come. There will always be some new DAC chip that comes into vogue or a new amplifier technology that is said to provide even more performance while improving efficiency, and the M33 would be hard-pressed to incorporate these, but I would not worry about this as the M33’s DAC and amplifier performance is quite good. On the software side of things, the BluOS system is very active and is updated often to include new streaming services and functionality, so chances are good that the M33 will be able to play most, if not all, of the streaming services you want. 

Who Is the Competition for the NAD M33?

The Anthem STR Integrated Amplifier is also $4,999 (buy at Crutchfield) and has very similar functionality to the M33. The Anthem is missing the M33’s headphone output and built-in streaming capabilities, and substitutes Anthem’s own ARC room correction system in place of Dirac. The STR provides 200 watts per channel into 8 ohms and doubles to 400 watts into 4 ohms. It even reportedly goes to 550 watts into 2 ohms. 

The JBL SA750 is less expensive at $3,000 (buy at Crutchfield) and includes a modern feature set behind a retro faceplate. Like the M33, it has a MM/MC-compatible phono input, Dirac Live room correction, and streaming. The JBL’s streaming functionality is less robust than the M33’s BluOS, but it is a Roon endpoint with MQA. The SA750 is a bit less powerful, with 130 watts per channel of Class-G amplification.  

The NAD C 700 is significantly less expensive at $1,599 (buy at Crutchfield), but has a reduced feature set without Dirac Live or MDC architecture. The NAD C 700’s amplifier is less capable than the M33, but should be more than enough to drive most modern speakers.

Final Thoughts on the NAD M33 Integrated Amplifier

All-in-one systems often compromise performance, power, or functionality. NAD beautifully balances these considerations with the M33 and delivers on all three fronts. In many instances, we see one (or more) of the categories severely lacking in comparison to the others, not here. You can source individual components that perform better, but I have yet to audition an all-in-one system that performs this well, or provides this rich a feature set.

I thoroughly enjoyed the ability of NAD M33 to let me listen to my favorite music, whether on vinyl or streamed through an easy-to-use interface while providing plenty of finesse and power to drive my Revel F328Bes to too-loud levels while maintaining control. Whether in my main room or with another pair of speakers, the M33 always remained composed, with a tight grip on the speakers. The ability to add in my pair of SVS PB-4000 subwoofers and providing excellent room correction via Dirac is a pleasant bonus. The M33 does all of this without dominating your listening space with a stack of components, it is one very attractive chassis that is full of performance and features that ably replaces a whole stack.