Technology and design

The Naim NAC 332 is the second component in the new Naim 300 range to be reviewed on SoundStage! Ultra. The 300 series is only the fourth generation of Naim amplification to be launched since the firm’s inception in 1973. Priced at $10,999 (all prices in USD), the NAC 332 preamp sits in the middle of Naim’s hi-fi separates series, above the new 200-series NSC 222 streaming preamplifier ($8999) and below the existing NAC 552 preamplifier ($32,000), which will continue in production unchanged, save for switching to white front-panel illumination. In effect, the NAC 332 replaces both the discontinued NAC 282 and NAC 252 preamplifiers with a single unit. It’s all part of a simplification strategy that’s admirable, not least because the NAC 332 is priced only slightly above the NAC 282 (currently retailing at $8599) and below the recently discontinued NAC 252 ($12,599).

Naim Audio

The NAC 332 follows the same design language as the Naim NSS 333 streaming DAC, which I reviewed last month, with a white Naim logo inset in a glossy acrylic panel at the center of the “triptych” preamplifier chassis. On the left side of the front panel is a large, illuminated volume control with a glowing, white outer edge. A ring of small, white LEDs on the volume dial illuminate when balance or volume is adjusted by the accompanying remote control. This is a very neat system, similar to that used by Leema Acoustics on its Constellation amplifiers (although those have the LEDs on the front panel around the volume dial).

To the right on the front panel are eight illuminated, circular buttons: one for power on/off, another for speaker muting, and six for input selection. The selected input and the output volume are also displayed on the color screen of the matching NSS 333 streamer when the two components are connected. It’s clear that a great deal of thought has been put into the integration and seamless operation of the 300 series.

Personally, after getting over the shock of the switch from green to white logos and lighting, I think the 300 series is the best-looking range that Naim has ever produced. The NAC 332 is recognizably a Naim device, yet it looks more luxurious than any of its predecessors. The buttons are attractive and tactile, and the gloss acrylic adds a great deal of class, as well as benefiting the sonics by reducing eddy currents in the chassis. The front panel also incorporates a headphone socket, which is claimed to better the performance of the firm’s standalone HeadLine amplifier.

Naim AudioNAC 332 main function buttons and headphone socket

The rear panel is comprehensively equipped with two balanced (XLR) inputs, three single-ended (RCA) inputs, and three Naim DIN inputs, one of which incorporates a tape loop. Outputs are well served, too, with XLR and DIN outputs for connection to any partnering power amplifier or subwoofer system. There’s also a switch on the rear panel to permit a floating ground, to assist in eliminating any issues with system hum. The most peculiar-looking connectors are the Naim Burndy sockets—huge multi-pin affairs that accept the hawser-like cables used to connect the optional NPX 300 power supply ($8999). Finally, there’s an IEC mains socket, plus some service ports.

The NAC 332 is supplied with Naim’s latest acrylic remote control, which uses the ZigBee protocol and thus isn’t line-of-sight. Yee-haw! The remote echoes the glossy acrylic of the casework, and all the buttons are backlit. It’s motion sensitive, so the backlighting switches on when it is picked up—someday, all remotes will be made this way. The corners are a bit sharp in the hand, but it works very effectively. As I highlighted in my NSS 333 review, I think that having separate remotes for the streamer and the rest of the system makes little sense. But according to customer feedback, that’s how Naim devotees like it, so who am I to argue?

Naim Audio

The manuals aren’t terribly impressive. I’ve passed a Class 1 pilot medical and even I struggled to read the tiny printed diagrams, so good luck if you don’t have the kind of eyesight that can pick out a Sukhoi Su-37 at 30 miles, closing at 1500mph: “He’s too close for missiles, so I’m switching to guns.” My demo units came from the factory via an Irish audio show, and were still running a preproduction firmware. I discovered that the balance control operated in reverse, so any attempt to shift the balance to the left actually sent it right and vice versa, which caused me a few minutes of head-scratching and wire-checking. After confirming that I hadn’t wired things up wrongly (there’s always a risk of a “senior moment” in this line of work), I called the factory and learned about the firmware issue. It’s important to note that this has been remedied for all production units, so isn’t a problem that will be encountered by anyone buying the product today.

For audiophiles, one slight negative is the fact that the NAC 332 comes out of the box with its signal output de-rated. This is because the company decided that the NAC 332 / NAP 350 combination is so powerful that unleashing its full output potential could lead to speaker damage if consumers inadvertently wind up the volume to max. Full output power can thus only be achieved after entering a specific button sequence on the front panel, the details of which are buried deep in the manual. I don’t know about you, but this is a bit too “nanny state” for my taste. If I buy a powerful car, I don’t want the manufacturer hobbling its performance in case I should decide to explore its outer limits—I don’t want the visceral savagery of the beast constrained in any way. I will concede, though, that this feature could be useful if young children with wandering fingers and a taste for technology are around.

Naim AudioNaim’s beautiful aluminum and acrylic casework is superb industrial design

Naim has incorporated a whole heap of innovation in its latest amplifier generation. Naim’s previous high-end preamps used the Alps Blue Velvet 27mm volume control, which, although sonically excellent, suffers from microphony and issues with channel balance. The NAC 332 uses a 100-step resistor-ladder volume control with reed relays. Custom-designed by Naim, this control is rated for 100 million operations, so should comfortably outlast even the most committed listener.

Both surface and through-hole mounting techniques are used to optimize circuit topology and sonic performance. Through-hole mounting of components is of course more resistant to vibration, and generally regarded as sonically superior. Polystyrene capacitors are used extensively; these perform better than competing technologies and offer zero leakage, but are expensive and have to be hand-soldered onto the boards. Teflon and polycarbonate caps are cheaper and easier to work with, but Naim wasn’t prepared to make such compromises.

Unlike the less-expensive NSC 222, the NAC 332 does not have a built-in phono stage. However, one of the NAC 332’s eight-pin DIN inputs can supply 18V DC to a compatible external phono stage, such as Naim’s NVC TT.

The NAC 332 incorporates a completely redesigned output stage, with the design goal to outperform the 552. Naim’s favored output format is XLR, and the output is impedance-balanced rather than differentially balanced. The use of DIN, XLR, and RCA connections means that this generation of Naim preamplifiers can more easily be incorporated into rival manufacturers’ systems.

As on all its predecessors, the NAC 332’s circuit topology is simple. Naim believes that simple circuits—when carefully designed and powered by highly stable power supplies—have a straightforward harmonic structure, with second- and fourth-order harmonic distortion that is barely audible but provides a certain enjoyable character. In the words of Steve Sells, Naim’s technical designer: “You can cancel these harmonics out, but you lose all the emotional impact of the music. Trying to accurately reproduce sine waves measured on a bench is simply a terrible way to design enjoyable amplifiers.”

If there’s a secret to Naim’s house sound and ability to convey emotion, it’s that, plus a level of mechanical attention to detail that is rare among audio firms. As an example, all Naim rear-panel sockets are compliantly mounted; the gas-tight contacts vibrate in sympathy with the cables vibrating in the room, but these vibrations are not passed back into the electronic circuits the way they would be if rigidly mounted. PCBs are often either compliantly mounted or sprung for similar reasons. Feedback is sparingly used, as Naim believes that too much negative feedback deadens the sound. The company measures and pairs individual circuit components to ensure symmetry and accurate channel balance, and the component reject rate is high. Point-to-point wiring is utilized in preference to circuit tracks in sonically critical areas, because it reduces electrical interference to the sensitive signal wiring. An obsessive level of care is taken for such wiring during manufacture, down to the optimal placement and orientation of cable ties in order to maximize sound quality and minimize microphony.

Naim AudioThe NAC 332 features the meticulous construction and point-to-point wiring characteristic of all Naim separates

The company recommends that its systems should be left powered up at all times for optimal performance. Units in the new range feature a soft-start function, with a standby switched-mode power supply that burns less than 0.5W. When a signal is detected, the conventional (and less efficient) toroidal power transformers come online for maximal sound quality at the expense of higher power consumption.

Listening: NAC 332 into the NAP 250

I began by running the NAC 332 into my reference Naim NAP 250 power amplifier, as this is an amplifier I know well. It’s worth noting that my resident NAC 82 preamplifier is equivalent to the NAC 332, albeit from two generations ago.

James Blunt’s “Goodbye My Lover” from the BBC Radio 2: The Piano Room (CD, Universal Music on Demand 5380207) is a notably simple recording, with Blunt accompanying himself on piano, and boy, does it demonstrate the sonic attributes of any system. From the opening bars, it was clear that the NAC 332 marks a significant swing back towards everything I have always loved about the original Naim amplifiers designed by Julian Vereker, rather than the slightly tamer and more controlled presentation of the models that followed. If the NAC 332 were food, it would be a juicy and tender T-bone steak, served rare and well-seasoned. It was raw, direct, simple, and enormously satisfying.

Naim AudioIf the NAC 332 were food, it would be a T-bone steak

The song opens with Blunt playing softly, but soon he’s heavily accenting his piano playing, hitting harder on the keys at moments of emphasis, unable to contain his emotion. The way the dynamic power and sheer attack of the Naim rendered the action of the piano’s hammers on its strings was utterly mesmerizing. On this track, the piano is clearly revealed as a percussive instrument: Blunt wrings every shred of emotion out of his monumental performance. In this song about an old girlfriend, Blunt lays himself bare.

I was struck in many ways by how similar the NAC 332 sounded to my NAC 82, another preamplifier that lives on the ragged edge. I fell in love with the NAC 332 instantly, but if you own a NAC 82 or 52, the newer preamp’s sonic signature will sound familiar. Yet, the NAC 332 has advanced the game in the sense of acoustic space around the performance. There was more depth, so that the artist appeared more tangibly in the soundstage. I also heard a shade more detail and a quieter, blacker background, which highlighted the importance of the space between notes even more effectively. The NAC 332 has a cleaner top end than its predecessors, so that the very highest frequencies sparkled rather than fizzed. Of course, the downside to this immediacy is that poorly recorded albums can sound a little unrelenting.

Adding the NPX 300 power supply

Bringing the NPX 300 power supply online made a very significant improvement to the NAC 332’s resolution and sonic presentation. During my review of the Naim NSS 333, I felt that the outboard power supply provided only subtle gains to the streaming DAC’s performance. But here, it fundamentally changed many aspects of the Naim preamp’s performance for the better, delivering excellent value for money.

Naim Audio

Replaying the Blunt track, it was apparent that he is at his vocal and emotional limit in this performance, his voice cracking with emotion as he grieves the loss of his former love. When Blunt wails “I’m so hollow, baby, I’m so hollow,” he perfectly conveys the grief one can feel at the end of a relationship. The NPX 300 brought even more detail and presence to the recording, and further revealed the power, authority, and rich timbre of the piano. The Naim system turned this recording into a performance—and a very moving one at that.

Next up was Elton John’s “Tiny Dancer,” from the album Madman across the Water (16-bit/44.1kHz FLAC, Universal Music Catalog / Tidal). Through the NAC 332—especially with the NPX 300 power supply onstream—the opening piano had greater richness and timbre than with my NAC 82, while elements like the subtle electric-guitar motifs had greater definition. In short, the ability of truly high-end audio to deconstruct a song and reveal how its various elements are combined was greatly enhanced. It was easier to follow each individual instrument in the mix. While the NAC 332 occasionally veered into stridency when self-powered, this tendency was tamed by the NPX 300. Using the optional power supply, the music was rendered with richer tonality and a far smoother and sweeter top end. In my judgment, the NAC 332 alone performed better than my Naim NAC 82 powered by a HiCap power supply, and had a similar sonic approach. Bringing the NPX 300 online elevated the NAC 332’s performance above that of the NAC 252–SuperCap combination, and brought the sound closer to the latter’s smoother, richer, and more refined presentation.

Listening: NAC 332 into NAP 350 monoblocks

The substitution of Naim’s new NAP 350 monoblock pair ($8499 each) for my resident NAP 250 power amplifier brought more bass slam, improved dynamism, and a sense of greater ease. Drums and percussion hit harder, and the tom-tom drums and bass guitar had greater solidity. Bass was frequently more tangible, and at times seismic. After gunning the Naim combo on “Need You Tonight,” from the INXS album Kick (16/44.1 FLAC, Rhino Atlantic / Tidal), the drums and bass were really moving air in the room through my ATC SCM40s. This is an infectiously danceable track, and it had absolutely superb rhythm, timing, and groove via the all-Naim system. It was hard to resist the urge to slip into full Michael Hutchence mode and start pouting and gyrating across the room. I’ve had the experience of doing just that during a review, only to turn around and see three of my daughter’s friends, faces pressed to the glass, watching me through the window with a look of amusement. That was no big deal when they were kids, but now that they’re uber-cool young women, I fear all dignity would be lost.

When you hear a system as finely optimized as this, it’s a little like jumping from the family car into something far more performance-oriented, like a McLaren. Suddenly, one’s senses and emotions are heightened. For several nights in a row, I played music deep into the night, eventually having to switch to headphones. Fortunately, the NAC 332’s headphone socket comfortably drove my AKG K701s and Beyerdynamic DT 880 Pros, and was a match for my standalone Beyerdynamic headphone amplifier.


The Naim NAC 332 is an extremely impressive performer, and a worthy successor to its acclaimed predecessors. I fervently believe that Naim’s new range is the most attractive overall the firm has ever made. I love the way that the design team has managed to maintain continuity with the brand’s heritage, while creating something even more elegant. That’s evident if you put a NAC 252 alongside the new NAC 332. The old model looks rather pedestrian by comparison. Sonically, the NAC 332—even when self-powered—is an excellent performer, with an impressive mastery of the essential building blocks of timing, dynamics, and bandwidth.

Naim AudioNaim’s new 300 series, the elixir of youth!

Bring the NPX 300 into play, though, and the quality of reproduction rises considerably, so that it comfortably outperforms even what I’ve heard from the venerable NAC 252 and SuperCap combo. Most pleasingly of all, I feel that the NAC 332 marks a return to Naim’s heritage sound—exciting, dynamic, emotive, and incredibly involving. It’s the kind of system that will keep you up at night and encourage you to approach music with the same passion and emotion in middle age that you felt at 17. In fact, I wouldn’t be at all surprised if owners of a Naim 300 system find themselves dwelling on lost loves and roads less traveled, because it’s a system that somehow reconnects you to your younger self and all of the emotions that entails. Maybe James Blunt has one.

. . . Jonathan Gorse

Associated Equipment

  • Turntable: Michell GyroDec turntable with SME Series IV tonearm and Audio-Technica ART-20 cartridge.
  • Phono preamplifier: Trichord Research Dino Mk 3 with Never Connected Dino+ power supply, PS Audio Stellar.
  • Streaming DAC: Naim Audio NDX, Naim NDX2, Naim NSS 333.
  • CD player: Naim CDI.
  • Preamplifiers: Naim NAC 82.
  • Power amplifiers: Naim NAP 250, Naim NAP 350.
  • Integrated amplifier: Leema Acoustics Tucana II Anniversary.
  • Power supplies: Naim HiCap, Naim NPX 300.
  • Loudspeakers: ATC SCM40.
  • Cabling: Chord Company Sarum T loudspeaker cables, Naim NAC A5 loudspeaker cables, Naim interconnects on all Naim amplification, Chord Co. Sarum T Super ARAY XLR, Chord Co. SignatureX Tuned ARAY DIN-RCA, Chord Co. SignatureX RCA-XLR, Chord Co. EpicX ARAY RCA. Chord Co. Chameleon interconnects for phono stages, QED interconnects for secondary sources.

Naim Audio NAC 332 Preamplifier
Price: $10,999; $8999 for the optional NPX 300 power supply.
Warranty: Two years, parts and labor.

Naim Audio Ltd.
Southampton Road
Salisbury SP1 2LN
United Kingdom
Phone: +44 (0)1722 426 600


North American distributor:
Focal Naim America
156 Lawrence Paquette Industrial Drive
Champlain, NY 12919
Phone: 1-800-663-9352