NAD Masters Series M32 DirectDigital DAC-Integrated Amplifier

Note: Measurements can be found through this link.

The M32 DirectDigital DAC and integrated amplifier ($3999 USD) is the newest offering in the second generation of NAD’s Masters Series, following the M22 stereo amplifier ($2999), M27 seven-channel amplifier ($3999), M17 A/V processor ($5499), M12 DAC-preamplifier ($3499), M50.2 digital music player ($3999), and M51 DirectDigital DAC ($1999). The M32 is also NAD’s second-generation DirectDigital integrated amp.

Description

Inside the M32’s outer shipping carton is a skeleton of matte-black cardboard. Lift off the top part to reveal the M32 and an inner box chock-full of accessories, including beautifully finished magnetic footers, an easy-to-understand quick-start guide, and a weighty USB stick of brushed aluminum buttoned to a classy leather holster. The remote control is of the big, multifunction variety, though its aluminum case could inflict real damage if you struck someone with it; when it’s picked up in the dark, a built-in light sensor activates its blue backlighting. At the bottom of the carton is another box containing not one but two power cords: a three-pronged version for grounded connections, and an ungrounded two-pronger.

Unpacking the M32 felt downright special. I have a lot of respect for NAD for wanting to keep that feeling intact -- the dollars and cents that go into such small details could easily have gone straight back into the company’s corporate coffers.

Removed from its protective drawstring bag, the M32 itself is not only a delight to look at, it’s built to a high standard. It weighs 17 pounds, and its entire case -- which measures 15.4”W x 5.3”H x 17.2”D -- is made of brushed aluminum and stainless steel. There are a 2/3”-thick front plate, aluminum side panels with narrow vents, and a multilayer top panel of contrasting sections of black and silver aluminum and eight grilles. The fit and finish were excellent. The front panel is dominated by a 4.5” thin-film-transistor (TFT) LCD touchscreen, flanked by a large weighted volume knob on the right and, on the left, the NAD logo. That logo is surrounded by an illuminated filament that glows orange to indicate standby mode, and white when the M32 is fully powered up. On the left, on the narrow surround below the protruding black front panel, is a 1/4” headphone jack; a capacitive power switch is mounted centrally on the top of the amp. Sitting on its magnetic footers, its volume knob the only control in sight, the M32’s clean lines and top-quality build wouldn’t look out of place on a product costing twice the price. Apparently, NAD has made no concessions in meeting the M32’s aggressively low price.

The M32’s circuitry is almost as impressive as its looks. Its heart is NAD’s DirectDigital amplifier, a class-D design built under license from Cambridge Silicon Radio. What makes the M32 unique is its sample rate of 844kHz, and its closed-loop error-correction, which compares the analog output signal to the digital input signal and matches them. Since there’s no traditional preamplifier stage other than the analog inputs, which use an A/D converter, all preamp functions are performed in the digital domain in 0.5dB steps via a 35-bit architecture. The M32’s digital signal is converted to analog just before it reaches the speaker terminals, which, NAD claims, results in the shortest signal path in audio history, a claim that I’m betting some other manufacturers might kindly object to. Combined with a custom switching power supply, the DirectDigital amp promises quiet, ultra-low distortion performance.

The M32 produces 180Wpc into 8 or 4 ohms, and remains stable down to 2 ohms. Its total harmonic distortion (THD) is less than 0.005% from 20Hz to 20kHz and from 500mW to 180W. What’s interesting about that THD specification is that it covers the entire audioband regardless of power output -- other manufacturers usually publish the results of a reading taken at 1kHz at an established power rating. The M32 generates a maximum of 18 amps of current, produces A-weighted signal/noise ratios of 95dB (1W) and 124dB (150W), and has a damping factor of 800.

There are few details about the M32’s built-in digital-to-analog converter. It has two optical inputs, two coaxial inputs, an AES/EBU input, and an asynchronous USB input that accepts signals of resolutions up to 24-bit/192kHz. (The M32 does not play DSD files.) It also has optical and coaxial digital outputs. Like its Masters Series forebears, the M32’s rear panel has four of NAD’s Modular Design Construction (MDC) slots, the first of which is already occupied by all of the M32’s digital inputs other than the asynchronous USB port. The remaining three slots can accept MDC modules for HDMI-1 (three inputs, one output; $299) and BluOS ($399); other MDC modules will be made available in the future. My review sample came with the BluOS module preinstalled; this supports BluOS, a proprietary streaming software platform from sister company Bluesound, as well as Bluetooth. (NAD, Bluesound, and PSB Speakers are all owned by the Lenbrook Group.) The BluOS module has two USB ports for local media, an Ethernet port to connect to a local network and the Internet, a Bluetooth antenna port, and a mini-USB port for BluOS firmware updates (which can also be done via the Internet).

Nonetheless, the M32’s connectivity is not digital only. Its rear panel also includes a full complement of analog connections: two single-ended RCA inputs, a moving-magnet phono input with RIAA equalization, and a preamplifier output that pulls double duty as a subwoofer output. Also included are an infrared input, 12V triggers, an RS-232 port, two pairs of five-way binding posts for those who wish to biwire their speakers, a USB service port, an IEC power inlet, and a master power switch. The M32’s discrete headphone amplifier is accessible via the jack on the front panel.

Setup and use

The first review sample of the M32 that NAD sent me was the very first production unit, and its speaker binding posts were wired incorrectly. The folks at NAD apologized profusely, sent me a second sample, and have since told me that they haven’t seen a repeat offender from their production line in China. Binding-post glitch aside, sample 2 was identical to sample 1.

While its hardware and connectivity are impressive, it’s the amp’s software interface, customization, and streaming prowess that set the M32 apart from any other all-in-one stereo amplifier costing up to $7500. Using its touchscreen made setting up the M32 a breeze. There are digital tone and balance controls. The amp’s output can be tailored to your loudspeakers’ average impedance, to maximize high-frequency performance. Inputs can be deactivated to avoid having to cycle through the amp’s many options.

The M32 was easy to hook up. I connected my KEF R700 loudspeakers to the NAD’s speaker terminals via a single run of DH Labs Q10 Signature cables, and my MacBook Pro music server to the M32’s USB port with a DH Labs Silversonic USB link. I selected the 4-ohm speaker output through the M32’s touchscreen menus to best match the NAD’s output signal to my KEFs, which have a nominal impedance of 8 ohms but trend far closer to 4 ohms through most of the audioband.

Then there’s BluOS. You connect the M32 to your network via the BluOS module’s Ethernet port, download the BluOS mobile app (iOS or Android) or desktop application (MacOS or Windows) to any devices you want to use to control the amp, and you’re ready to stream music. I was immediately able to start playing music from my iPhone 7 through the M32.

The list of music sources supported by the M32 is staggering: CalmRadio, Deezer, Groove, iHeartRadio, Juke, Murfie, Napster, Qobuz, Roon, Slacker, Spotify, Tidal, and WiMP. Syncing my Roon and Tidal accounts was a cinch, as was playing local content from my iPhone 7. BluOS worked, and worked well. The interface isn’t perfect, which is hardly a complaint given the fact that it supports so many different music sources. Still, the M32 is, by some margin, the most flexible DAC-integrated amplifier I’ve ever used. Between its wide range of analog and digital inputs and outputs, software interface, and software compatibility, it can play just about any role you want it to. I was good to go.

Listening

As soon as I plug in a new power amplifier and turn it on for the first time, I listen for its noise floor. Almost every integrated amp I’ve reviewed has been inaudible from my listening position, which is 8’ away from my KEF speakers. But usually, when my ears are within 12” to 18” of one of the tweeters, I can make out some low-level white noise. Some of the best amps I’ve tried -- Devialet’s Expert 130 Pro DAC-integrated ($7690) and T+A Elektroakustik’s PA 2000 R integrated ($8500) -- were audible only when I got my ear within an inch of the tweeter, and even then they were barely audible. NAD’s Masters Series M32 DirectDigital was about as quiet as the Devialet and T+A, despite costing only about half as much. A propitious start.

I turned to “The Lonely Night,” from Moby’s Innocents (16-bit/44.1kHz FLAC, Mute), to hear singer Mark Lanegan, and was blown away by the NAD’s startling transparency and soundstaging. This spacious recording sounded cavernous in my listening room -- I could easily hear into the recesses of the recording venue, which seemed to make the front wall of my listening room evaporate. Lanegan’s voice has a smoky, gravelly quality not unlike Tom Waits’s, and this recording of it leans to the hot side of neutral. I heard his deep vibrato and plenty in the way of sibilants, but was surprised to also hear copious amounts of inner detail -- I’d even call the sound airy. The M32’s stereo imaging of Lanegan’s voice was excellent, with little ambiguity and clear delineation of its boundaries, as well as strong dynamic contrast with the backing instruments -- his voice really popped from this recording, which I attribute to the NAD’s subterranean noise floor.

For music far less intimate, I cued up “Brothers in Arms,” from Tom Holkenborg’s sensational film score for Mad Max: Fury Road (16/44.1 FLAC, WaterTower Music). This orgy of noise is rife with drums and other percussion, strings, bass, and synths, all played by Holkenborg and built up in layers of sound. It careens from discord to harmony, chaos to aspiration, in barely controlled instrumental violence. I pushed the M32 hard but heard nary a hint of compression or edginess. The NAD produced a vibrant, überclean sound that excited my senses as I indulged in such boorish delights as “Brothers in Arms.” The frenetic strings had metallic zing, while the impact of the drums was downright addictive, not so much for their power as for their concussive quality. The attacks and decays of every instrument were reproduced with remarkable speed and authority. This was no shrinking violet of an amp -- Holkenborg’s sound world was laid bare without romance, or any downplaying of its intended savagery. If you’re looking for midrange bloom -- or aural editorializing of any kind -- the M32 is not the amplifier for you.

And yet the M32 didn’t make the mistakes that many digital amps of ten years ago did. Their sound was generally cold and sterile, a touch clinical and hard, with an unrefined upper midrange and lower treble masquerading as previously unheard inner detail. Instead, the M32 had a perfectly neutral tonal balance, but was so quiet and resolving that voices and instruments tended to pop in a way that more traditional class-AB amps can’t quite muster. Take, for instance, Enya’s performance of “O Come, O Come, Emmanuel,” from her And Winter Came . . . (16/44.1 FLAC, Reprise). Her voice sprang from precisely between my KEF R700s, almost entirely disconnected from the speakers themselves, and sounding anything but veiled. Indeed, her punctuated delivery was deliciously rendered: totally unvarnished, stripped of any and all of the distortional artifacts that ever so subtly mar this recording through most other amplifiers. I could hear every inflection of her phrasing, and loved every second of it.

The M32’s discrete headphone amp was terrific. I hooked up my over-ear headphones -- NAD’s own Viso HP50s -- and played “In a Black Out,” from Hamilton Leithauser and Rostam’s I Had a Dream that You Were Mine (16/44.1 FLAC, Glassnote). Leithauser’s voice is somewhat like Bob Dylan’s; light, lilted, and a bit nasal. It rang beautifully through the Viso HP50s, with an airy, well-defined, centered image as plucked strings danced in both channels, perfectly framing his reverberant crooning. Like every other aspect of the M32, its headphone amp is well executed, and no mere afterthought.

Comparison

Devialet’s Expert 130 Pro is the best integrated amplifier I’ve ever listened to. Its Analog Digital Hybrid (ADH) amplifier, which produces 130Wpc into 6 ohms, offers state-of-the-art sound that marries the finesse and purity of class-A operation with the power and thermal efficiency of class-D. Like the NAD, the Devialet eschews a traditional analog preamplifier in favor of having its built-in DAC drive the ADH directly. It’s as quiet a circuit as I’ve ever heard, boasts exceptional noise and distortion specs, and delicately balances being brutally revealing with sounding emotionally involving.

The NAD M32 doesn’t quite match Devialet’s golden mean, falling a bit short in the intangible “musicality” department. Compared to the Devialet, voices and instruments were a little two-dimensional through the M32, without the kind of midrange texture that can fool me into thinking flesh-and-blood performers are being re-created in front of me. But -- the NAD sounded every bit as resolving and transparent as the Devialet, while, at $3999, costing far less than the Expert 130 Pro’s $7690. That’s a big achievement.

A more likely comparison for the M32 might be my reference DAC-integrated amplifier, Hegel Music Systems’ H360 ($5700). The H360 produces big power -- 250Wpc into 8 ohms or 420Wpc into 4 ohms -- while offering plenty of current. It also packs an excellent D/A converter. But next to the NAD, the Hegel’s all-black housing of folded aluminum, basic alphanumeric display, and lack of a custom app make it look and feel and function like a relic. Sonically, it’s a mixed bag. The Hegel’s prodigious bass performance equals the NAD’s impact and athleticism, with more weight and slam; I found myself preferring the NAD’s lighter touch. The H360 couldn’t quite match the NAD’s ability to unearth even the smallest low-level details, but made up for it by offering a more lifelike midrange -- through the Hegel, voices were more palpable, instruments sounded fuller. But there’s no escaping the value component. Including NAD’s MDC BluOS module, the M32 costs $4398 -- still $1302 less than the Hegel H360 -- and gives you more of just about everything other than power output. And even then, the M32’s 180Wpc should be more than enough for just about anyone. Wow.

Conclusion

NAD’s Masters Series M32 DirectDigital DAC-integrated amplifier impressed me from the moment I cracked its shipping carton. From packaging to build quality to connectivity to, most important, sound quality, the M32 is an outstanding example of how audiophiles don’t necessarily have to spend top dollar to get top-shelf performance. It not only can do just about anything asked of it, it does it all uncommonly well, and virtually without compromise. I haven’t encountered many bona-fide bargains in high-end audio, but this is one of them. It’s shockingly good, and a benchmark product at this price and well beyond.

. . . Hans Wetzel

hansw@soundstagenetwork.com

Associated Equipment

Loudspeakers -- KEF R700

-- KEF R700 Earphones and headphones -- NAD Viso HP50, Pryma 01, PSB M4U 4

-- NAD Viso HP50, Pryma 01, PSB M4U 4 DAC-Integrated amplifiers -- Devialet Expert 130 Pro, Hegel Music Systems H360

-- Devialet Expert 130 Pro, Hegel Music Systems H360 DAC-headphone amplifier -- Oppo Digital HA-2SE

-- Oppo Digital HA-2SE Source -- Apple MacBook Pro running Tidal and Roon

-- Apple MacBook Pro running Tidal and Roon Speaker cables -- DH Labs Q-10 Signature, Dynamique Audio Caparo

-- DH Labs Q-10 Signature, Dynamique Audio Caparo Analog interconnects -- Dynamique Audio Shadow (RCA), Nordost Blue Heaven LS (XLR)

-- Dynamique Audio Shadow (RCA), Nordost Blue Heaven LS (XLR) USB link -- DH Labs Silversonic

-- DH Labs Silversonic Power Conditioner -- Emotiva CMX-2

NAD Masters Series M32 DAC-Integrated Amplifier

Price: $3999 ($4398 as reviewed, including MDC BluOS module).

Warranty: 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