Naim Audio NSS 333/NAC 332/NAP 350 DAC/Pre/Power System

hfnoutstandingThe second phase of Naim's 'New Classics' launch brings a new streamer, a preamp and monoblock power amps, all in redesigned slender casework. Are they true 'classics'?

At times of late, it seems Salisbury's Naim Audio is wilfully courting controversy. It's been causing ripples with the brand's faithful fans ever since it launched its all-in-one Mu-so systems and second-generation Uniti products. It wasn't that these arrivals were on a mission to make hi-fi simpler for all, eschewing the tweakery and 'black magic' once suggested as a prerequisite for realising its true potential – no, what broke the usually calm surface was the fact the Naim logo, for decades lit in green, had turned white. Cue Naim aficionados fanning themselves like Edwardian grandes dames with a fit of the vapours.

Now the 'New Classics' products have taken a very substantial boulder and hurled it into the millpond, for not only are the logos white, there's a new take on the company's solid alloy casework, with a large notch through the upper surface and – the horror – Naim has embraced balanced XLR connections. That's apparent in the latest 300 series models, launched at this year's Munich High End Show – there's the NSS 333 network player/DAC and NAC 332 preamplifier, at £7933 apiece, and the NAP 350 monoblock power amplifier, yours for £12,340 per stereo pair.

Stream On Tap
The arrival of the 300 series was signposted when Naim launched its first 'New Classics' – the NSC 222 streaming preamp and latest-generation NAP 250 power amp – at the beginning of 2023, priced at £5700 apiece. With them came the NPX 300 outboard power supply, Naim hinting it would offer similar potential for forthcoming models. Now those models are here, and that power supply can be added to either the NSS 333 or the NAC 332 to enhance their performance, with separate Burndy cables for digital and analogue sections.


[From top] new slimline casework is shared by the NSS 333 streamer/DAC, the NAC 332 preamp and NAP 350 mono power amp(s). The NSS 333 is largely driven via its 5.5in colour touchscreen and app [see boxout, p44], the NAC 332 by input buttons, volume and remote

The NSS 333 is based on the same 'platform for the future' Naim developed for its second-generation Uniti models [HFN Nov '17], and which now sits at the heart of all the company's network audio products. Built from the start to be software-upgradable to take account of changes in the streaming landscape, the NP800 board offers both local and online streaming, including UPnP streaming from a NAS or similar storage, plus support for services including Spotify Connect, Apple Music, Tidal/Tidal Connect and Qobuz. It also has integrated AirPlay2, Chromecast and Bluetooth AptX for wireless streaming from smartphones, tablets and the like, and is Roon-ready.

Digital-to-analogue conversion is provided by Naim's favoured PCM1791A DAC from TI/Burr Brown but running with a custom 44.1kHz/48kHz-synchronous digital filter. As well as wired and wireless network connections, the latter using twin antennae hidden away behind the player's heatsinking, the NSS 333 also offers two optical and two coaxial digital inputs. There are also two USB-A connections – one front, one rear – to which external storage can be connected.

Dual Remotes
Depending on the input, the NSS 333 will accept files at up to 384kHz/32-bit and DSD128, and control is via either the RF Zigbee handset supplied, or the excellent Focal & Naim app. The Zigbee system can also be programmed to link the NSS 333 and NAC 332 for one-handset control because, as standard, the two units come with slightly differing remotes. There's also Naim's wired system automation connection between the network player and preamp, and indeed on to the power amps, to allow synchronised operation. This uses an optical hook-up in the New Classics products, avoiding the possibility of ground-loops and allowing secure control over long distances – think tens of metres – at sensible cost.


Burndy sockets support external PSUs for the NSS 333 [top] and NAC 332 preamp [middle]. The '333 has 2x coax, 2x opt, USB-A and network digital inputs (up to 384kHz/32-bit and DSD128) with DIN, RCA and balanced XLR outs feeding equivalent ins on the '332. Three pairs of RCAs/two pairs of XLR outs are offered while the NAP 350 [bottom] has one balanced XLR in and one inset pair of 4mm speaker cable sockets

As well as a balanced XLR output, and RCAs, the NSS 333 also has a DIN output for Naim traditionalists, the preferred option chosen via the player's configuration menu. DIN inputs are also provided on the NAC 332 preamp. In fact, there are three, including one able to supply 18V power to external phono stages such as the NVC TT, along with three sets of RCA inputs and two pairs of XLRs. However, the output here is on RCAs and XLRs alone, along with a front-panel headphone socket.

Control and audio circuits are kept separate using galvanic isolation, and input switching is via reed relays, with programmable input sensitivity, AV bypass mode and mapping of inputs to the sockets – so you could have any of the six inputs on RCA, XLR or DIN. The NAC 332's volume control also uses reed relays and fixed resistors for superior sound quality, all governed by an optical encoder and the kind of smooth-acting oversized illuminated rotary control also found on Naim's Statement [HFN Jun '15], Uniti [HFN Aug '21] and Mu-so units. Finally, like the network player, the preamp uses two power supplies – a linear PSU feeds the unit when operational, giving way to a small switchmode PSU when in standby.


The NSS 333's large toroidal transformer [bottom right] feeds 4x PSUs for the NP800 streaming card [top right], ARM CPU [top right, centre PCB], DAC and SHARC DSP [top right, lower PCB] and Class A preamp stage [top left]

New Mono Era
The NAP 350 power amp marks a return to mono amplification in Naim's mainstream, recalling the NAP 135 of yore. With its rated 175W/8ohm claimed to almost double into 4ohm, the new amps are a step up from the (also) new NAP 250's 100W stereo output. In practice, the NAP 350 slots in below the 'old' NAP 500 DR [HFN May '16], which at £26,000 actually offers less power than a pair of NAP 350s at 140W/8ohm. The big stereo power amp, some 13 years on from launch and eight since its last upgrade, might now be living on borrowed time...

Anyway, the NAP 350 has only a balanced XLR input, so a 'legacy adapter lead' would be needed to use it with anything other than a balanced preamp, Naim having a range of such cables available. Its speaker outputs are only on a pair of 4mm sockets, for which Naim supplies a two-pin solderable speaker plug in the box.

Discrete Regulator (DR) power supplies are used, with a soft-start sequence for the toroidal transformers to stop them tripping domestic circuit-breakers, and the amp uses eight custom-design NA009 power transistors across its power supply and output stages, as originally developed for the Statement project. As in other Naim implementations of these devices, they're mounted to the heatsinking using ceramic insulators.

Naim Audio Ltd, Salisbury
Supplied by: Naim Audio Ltd
01722 426600