These are interesting times for an aficionado of high-end audio gear. Consider this: ESS Technology’s Sabre Reference ES9018 DAC chip can be found in products costing over $30,000 that are claimed to be the state of the art -- and just may be. You can find the same chip in products costing under $1000.
I know what you’re thinking, and you’re right: What matters is how the Sabre -- or any chip -- is implemented. I can guarantee that in the $30k product you get a much more substantial power supply and analog output stage. Still, the guy with the $1000 DAC with Sabre chip aboard probably feels pretty good about what he has. And it probably sounds pretty good, too.
It’s the same with amplifiers. There’s no question that the Hypex class-D amplifiers developed by Bruno Putzeys have a loyal following. Various Hypex modules are showing up not only in DIY circles and plate amplifiers for subwoofers, but in highly acclaimed commercial products that challenge the state of the art. It’s not an overstatement to say that Hypex is shaking the amplifier world.
Then, to shake things up even more, along comes NAD. Their Masters Series M22 stereo amplifier ($2999 USD) is based on a Hypex Ncore class-D amplifier module and a “well regulated, but not too tight, custom switch-mode [power supply] design . . . [that] allows maximum dynamic power, very high current yet with very low distortion.” If you’re thinking, “Wow, an NAD-Hypex collaboration could be quite powerful!,” you’d be right. NAD’s Greg Stidsen expanded on the NAD-Hypex partnership:
We developed the M22 in consultation with Hypex, but with a lot of NAD’s Bjørn Erik Edvardsen’s ideas about amplifiers included in the final design. Ncore is a very specific output-stage topology that is very highly optimized and can’t really be “tuned” or changed. While the power supply must be contoured to the requirements of the Ncore circuit, the power supply and earlier amplifier stages that drive the Ncore were designed by NAD and reflect our design values of high dynamic power and low distortion into difficult loads.
The underlying concept of Ncore has been around for a long time -- but nobody could get it to work in a practical way. It is like jet propulsion -- even though rocket technology goes back hundreds of years, to the Chinese, making a jet plane took a lot longer! Class-D amplifier technology is bit like that. We have finally surpassed the best linear amplifier technology with switching amplifiers.
NAD claims that they have achieved 0.003% distortion at any power level, at least in part because of “an added control loop incorporating an integrator with adaptive clipping [that] enables 20dB more feedback to be used across the audioband because of its extremely low-phase shift resulting in a dramatic reduction in distortion across the audioband.” Negative feedback has had a bad reputation in high-end circles for years, and as implemented in some earlier products, that bad rep was well deserved. But that not all negative feedback is bad has been proven by recent products such as these Ncore-based amps, as well as super-expensive, great-sounding models from companies such as Boulder and Soulution.
The Masters M22 (17"W x 4"H x 14.8"D, 19.6 pounds) is specified to deliver 250Wpc into 8 or 4 ohms, both channels driven. The dynamic power rating is much higher, though: 355 or 640Wpc available into 8 or 4 ohms, respectively. The M22 can even supply 50A of current into 1 ohm for 1ms -- it’s a real-world powerhouse. The A-weighted signal/noise ratio is 100dB at 1W output, or 120dB at the rated power output. (Make sure you’re comparing apples with apples -- either at 1W or rated power -- when examining two models’ spec sheets.) A high damping factor of 800 (50Hz-1kHz, 8 ohms) promises good driver control and, hopefully, tight, tuneful bass.
The M22’s natural companion is the Masters Series M12 preamplifier-DAC ($3499 base price, $3948 as reviewed), which measures 17"W x 5.2"H x 14.8"D and weighs 17.8 pounds. Actually, “preamplifier-DAC” only begins to describe the M12’s functionality. The first thing you need to know about the M12 is that it incorporates NAD’s Modular Design Construction (MDC), which permits some customization of its input capabilities. Fixed rear-panel features (i.e., not MDC) include RCA and XLR stereo outputs for connection to your power amplifier, as well as two RCA outputs labeled SUBW1 and SUBW2, for connection to powered subwoofers. Optical and coaxial digital outputs are also standard. On the MDC side -- the left, when looking directly at the rear panel -- is a module for analog inputs: RCA phono complete with a phono ground connector, and stereo RCA and XLR jacks. To the right of these are the standard digital inputs: two coaxial (RCA), two optical (TosLink), and one AES/EBU (XLR).
Lenbrook, parent company of NAD and PSB, also makes Bluesound products. (See Kevin East’s fine review of the Bluesound suite of streaming products on SoundStage! Xperience.) I asked that my review sample of the M12 include the optional DD BluOS module ($449). This includes two USB inputs, a LAN input for connection to a home network, and an antenna connection to extend its Bluetooth range for pairing with an Android or iOS device. BluOS can be used to stream a variety of music services, such as Spotify, Deezer, Juke, Murfie, Qobuz, Rdio, Slacker, TuneIn -- and my choice, Tidal. Next up are the direct connections for your computer, with two ports: one USB Type-B input for direct connection to your computer, and a USB Type-A input for hooking up a USB hard drive. You can also add, to a third empty MDC bay, the DD HDMI-1 module ($299), which gives you three HDMI inputs, and an HDMI output capable of passing along 3D video to your display device.
The M12’s front panel is dominated by a central touchscreen and, to the right, a large rotary knob. The touchscreen has five displays: Main, Media, Mode, EQ, and Setup. In Main, you scroll through the available inputs. Media displays the artist name, track title, and album title of whatever music you’re feeding the M12 -- as I write this, I’m streaming “Never Gonna Let You Down,” from Colbie Caillat’s Gypsy Heart (16-bit/44.1kHz Tidal, Republic). The sample rate is shown on Main. The Mode display lets you adjust absolute polarity, while EQ activates or defeats the Bass, Treble, and Balance controls. Using Setup, a subwoofer can be integrated into the system, with selectable crossovers for both the main outputs to your speakers and the signal that would feed the sub. Setup also allows for some adjustability for Source, Digital Output, and Control. At the bottom of the faceplate, directly below the big knob, is a USB Type-A port to accept a memory stick full of music. A nicely weighted multifunction remote allows control of all of the above functions.
The M12 controls volume in the digital domain. According to NAD, this doesn’t result in a loss of resolution, even for files of the highest bit depths and sample rates, because the volume control uses a 35-bit data path, which NAD says ensures that 24-bit material can be played at full resolution at any volume setting.
The M22 and M12 share a number of construction details. I remember seeing the original prototypes of the new Masters Series models at the 2014 Consumer Electronics Show, and being impressed with their looks. Each features a thick, brushed-aluminum, silver backing plate, over which are laid the three segments of the faceplate proper, made of a material like black acrylic. Silver side panels, vented near the bottom, wrap around the top corners to meet the black top panel. The top plate has eight rectangular vents with silver reveals that punctuate the distinctive silver/black look. You don’t have to choose silver or black when ordering an NAD Masters Series component -- you get both. I wouldn’t classify the Masters Series components as heavy-duty, or audio jewelry in the purest sense, but they sure are smart-looking products that should fit most any décor.
Use
I used the M12-M22 combo with my MacBook Air laptop and my iPhone 6. With the Air, I listened to a connected hard drive containing my CD collection, as well as numerous downloads at varying resolutions. Using my iPhone 6 and NAD’s Controller app, I had a blast streaming CD-quality music from Tidal. Once you get comfortable streaming music, you may not want to go back to any other way. I found the BluOS connection between my phone and the M12 to be solid. It worked fine all the time, and kept working even when I received a phone call.
I auditioned the Masters Series M22 stereo power amplifier and M12 preamplifier-DAC together. All comments about their sound apply to the pairing.
Sound
I often hear complaints from audiophiles -- usually older ones -- about the sound of class-D amplification. But usually, when I drill down to what those opinions are based on, I learn that the listener’s experience is limited to an ICEpower-based amplifier of five years ago -- or some other limited, older sample size. But just as all class-A, solid-state amplifiers don’t sound the same, neither do all class-D amps. And if all you’ve heard are older class-Ds, all bets are off.
I always seem to listen first for noise, which I find hardest to “listen around.” When the first thing I hear is a higher-than-normal noise floor, I’m probably already subconsciously questioning the product’s quality. True, many times, once music is playing, you don’t focus on the noise as you do when you’re assessing the noise levels with no music playing. But that doesn’t mean the noise doesn’t affect the overall sound.
The NADs were very quiet in my system. In fact, they’re among the quietest sub-$10,000 components I’ve heard. Yes, you’ll hear a faint hiss from your speakers, but no mechanical noise, such as the humming of a large transformer. This boded well for my initial impressions: Music emerged from the sort of black backdrop that helps suspend disbelief. When I listened to “Arms,” from Christina Perri’s Lovestrong (16/44.1 Tidal, Atlantic), I heard pristine guitar sound in the opening few seconds, before Perri starts singing. And when she did, it was easy to focus on her voice -- there was a clear delineation between her and the accompanying instruments on the studio-assembled soundstage. Imaging was sharp, if not hyperrealistic, and the size and stability of the soundstage remained consistent.
You’ve probably heard that class-D can do great bass. That, in my experience, has been true of all class-D amps, to somewhat varying degrees. The M22 and M12 produced punchy, clean bass that left me wanting almost nothing in the lower registers. When I listened to “Low,” from Jonas Hellborg’s The Silent Life (16/44.1 ALAC, Day Eight Music), I was greeted with more control and greater depth of bass than I hear from most solid-state electronics, regardless of price. I could hear low-level detail in this bass-heavy music with ease; it capably illustrated the resolving chops of the M12’s DACs. The bass was sustained and strong, indicating that the M22 had sufficient headroom -- always a trademark of NAD amps. This Ncore-based variant upholds that tradition.
To better explore the NADs’ resolving capability, I cued up Jerry Junkin and the Dallas Wind Symphony’s Crown Imperial (24/176.4 WAV, Reference Recordings). Not only could I easily hear even the most minute, lowest-level sounds in this work, but the scale of the soundstage was reproduced with appropriate scale and confidence-inspiring solidity. The M22 and M12 never sounded strained, regardless of the music I played or the volume level I used. I feel that these two components could form the heart of a very-high-resolution audio system -- their sound character didn’t change with the output level or musical genre, but remained consistent at all times. They were rock solid.
I’ll throw in the usual caveat: If you like a tubey sound, one with more warmth in the midrange and a mellower top end, the NADs might not suit your tastes. But I suspect that most readers already know that, and there are certainly many tubed amplifier-preamplifier combinations available at similar prices to the NADs. Perhaps the better comparison is with other solid-state components. My reference system includes the much more expensive Ayre Acoustics KX-R Twenty preamplifier ($27,500) and MX-R mono power amplifiers ($18,500/pair, discontinued), fed by either a Hegel Music Systems HD12 ($1250) or an Exogal Comet ($2500) DAC. I listened to Natalie Prass’s self-titled debut release (16/44.1 Tidal, Spacebomb) -- a fine album for assessing a component’s reproduction of women’s voices. Through the Ayre-based system the midrange was silkier and smoother than through the NADs, but just as resolved. A smooth midband with no loss of detail is the Ayre’s wheelhouse -- very little else comes close. I don’t want to find too much fault with the NADs here, especially considering the immense difference in price, but the Ayres did outclass the NADs in this regard. The Ayres also threw a larger, more enveloping soundstage, particularly with live recordings, though this was a closer call.
One area in which some listeners might actually prefer the NADs is the bass. The Ayres reproduced bass in a softer, more rounded manner; the NADs were tighter and more authoritative, especially with music such as Jonas Hellborg’s. The NADs just didn’t seem to run out of steam when the going got tough and I played bass-heavy music at high levels. The word that comes to mind is propulsive.
Conclusion
The NAD Masters Series M22 stereo power amplifier and M12 preamplifier-DAC are easily recommendable, for a variety of reasons. The M12 is, in my opinion, an example of what tomorrow’s preamps will be: they’ll have analog inputs, but with a clear priority given to digital inputs; streaming capability, and a good app for its control (this is absolutely huge in importance); functionality for a 2.1-channel system; even a front-panel USB port. Basically, the M12 lets its users listen to music in every manner possible, without limiting them due to lack of connectivity or functionality. And with the M12 paired with the M22, the sound was never short of excellent. The NADs were quiet and confident, and strode through every musical test I threw at them with ease and poise. Although in some areas, such as the midband, they can be bettered by far more expensive electronics, they easily hung in there in such areas as bass tightness and depth.
Overall, NAD’s Masters Series M22 and M12 are nicely made, solidly performing components that give you access to music through a variety of delivery methods. That they do so while sounding really good with all of them should lead to many hours of enjoyment. If you get a chance to hear these, leave any preconceptions at the door and just . . . listen.
. . . Jeff Fritz
jeff@soundstagenetwork.com
Associated Equipment
- Speakers -- Magico Q7, PSB Alpha, Triangle Magellan Cello
- Amplifiers -- Ayre Acoustics MX-R monoblocks
- Preamplifier -- Ayre Acoustics KX-R Twenty
- Digital-to-analog converters -- Hegel Music Systems HD12, Exogal Comet
- Sources -- Apple MacBook Air running OS 10.9.4, iTunes, Amarra 3.0.2, DSDPlayer for Mac; iPhone 6
- Cables -- Nordost Valhalla interconnects, speaker cables, power cords; Siltech Explorer speaker cables, interconnects, power cords
NAD Masters Series M12 Preamplifier-DAC
Price: $3499 USD.
NAD Masters Series M22 Stereo Amplifier
Price: $2999 USD.
Warranty (both): Three years parts and labor.
NAD Electronics International
633 Granite Court
Pickering, Ontario L1W 3K1
Canada
Phone: (905) 831–6555
Fax: (905) 837-6357
Website: www.nadelectronics.com