Naim DAC

This review was written in 2009 and has only ever been published on the internet.

Naim_DAC

The arrival of a DAC from Naim was inevitable, and designs have been on the drawing board in Salisbury for quite some time. However, the company saw no reason to produce a stand-alone converter when the only potential feed for it was a CD transport: why, it reasoned, move the DAC a cable-length away from the source of the data, re-engineer the player to include a second output, and suffer poorer performance just so the DAC could be in a separate enclosure? It made no sense, so Naim stuck to its traditional methodology and made its ‘second’ CD boxes the power supplies.

Times change, however, and with the current proliferation of mixed digital sources Naim agrees that there is now a benefit to be had from discrete DACs. They can usefully be deployed with streaming devices, such as the Logitech Squeezebox, with music stored on computers and networks, internet radio from the same, PC and Mac laptops with digital music onboard, and with hard disk players such as Naim’s own HDX. They can also be used to improve the performance of portable music devices from USB sticks to the ubiquitous iPod, not to mention games consoles and the like. And, if properly implemented, they can be used to upgrade the performance of suitable CD players, even though, in some circles, CDs are now – I think rather ridiculously and prematurely – being referred to as a “legacy” format.

The Naim DAC is, as one has come to expect from the company, a little out of the ordinary. Naim refuses to produce “me too” products; those that exist merely because every other manufacturer has one in its portfolio. On the contrary, Naim insists that its products perform better, fulfil more requirements, or, ideally, meet both of those criteria. The DAC is no exception. You can read about its performance later but take a look at what is on offer here: to begin with there are 10 inputs; two coaxial BNC and two coaxial RCA (phono) along with four TOSlink optical connections; and there are two USB inputs, with the front-panel port taking precedence over the connection on the rear panel if devices are connected to both simultaneously. The DAC also includes an Apple Authentication Chip making it capable of extracting digital data from recent iPods and iPhones, and also making it the world’s first Apple-Authenticated high-end digital to analogue converter. That, one would hope, ought to be sufficient for most people but the S/PDIF connections, which are likely to be the most commonly employed, are not just run-of-the-mill types that one can find anywhere: they claim to operate with absolutely no added jitter. The audible results of this are quite remarkable but let us not get ahead of ourselves here.

Opinion in some quarters has it that there is nothing especially difficult about building a DAC: it is no more complicated, say some, than picking a DAC chipset and then slavishly following its manufacturer’s application notes because the manufacturer obviously knows best how to implement it. That, in my opinion, is an extremely naive and decidedly crass way to look at the situation. It can also be disingenuous depending upon who is voicing that opinion. For starters, what if the chipset manufacturer does not know best? What if, for example, he considers pricing to be a greater concern than absolute performance? And they are not as horrifically expensive as some retail prices might suggest: manufacturers can buy a decent quality DAC chip for around $20 a piece, or a lower grade option for under a dollar. So, ask yourself this if you are looking for audiophile-grade sound: do you think that a company that is churning out hundreds of models of DAC chips, some costing as little as 60 pence, could justify evaluating them with the same rigour as a specialist audio manufacturer?

Then there is the question of the power supply type and its sophistication, not to mention the myriad questions that attend the type chosen – switched mode or analogue and, if the latter, the amount of regulation applied. And this all comes before considerations such as EM/RF Interference, which are influenced by such things as the PCB design and layout, once again not mentioning items including ancillary components, casework and the effects of internal and external vibration. This is not exaggerating the situation: during the design of the Naim DAC its engineers even measured electrical changes in components when they were gently breathed upon. Naysayers please note that all-important word measured: these differences were observed on scientific, objective, measuring apparatus so they are not fanciful, delusory artefacts dreamed up by an overactive, subjective imagination.

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PCB (printed circuit board) isolation is one of the multitude of factors to which Naim pays great attention. When I enquired why the power supply board was isolated from the rest I learnt that it was because the capacitors on it could vibrate as they went through their charge/discharge cycle and that that vibration was not wanted anywhere else on the board because of its potential to cause audible disturbances in sensitive components.

Returning to the zero jitter S/PDIF aspect of the Naim DAC, this industry-standard means of transferring digital audio externally, is nowhere near a perfect medium. The DAC has to recover timing data from a tri-partite signal containing the audio data, and the word- and bit-clock signals. Unfortunately, that recovered clock signal can be modulated by the other data resulting in jitter. The usual way of minimising the effects of these errors is by using a phase locked loop (PLL) to compare the incoming signal with a regenerated clock and so reduce these short-term variations. Using sequential PLLs can reduce these variations even further but this is not the approach Naim has adopted for its DAC.

Naim’s buffer method of jitter removal employs a simple concept: the audio data is clocked into random access memory at the incoming, inconsistently timed rate and is then clocked out of that buffer and into the DAC chips using a precise master clock. Normally, DACs use an ASRC (asynchronous sample rate convertor) or a VCXO (voltage controlled crystal oscillator) to match their clock frequencies to that of the S/PDIF datastream. Neither methodology was deemed appropriate for the Naim DAC, although it does use the integral ASRC in the SHARC DSP digital filter when the data falls outside the S/PDIF specification. Instead, the DAC offers 10 different fixed frequencies that are selected to keep the average clock frequency the same as that of the source. The required oscillator is chosen by the SHARC DSP, which precedes the pair of mono, multi-bit Burr-Brown PCM1704K DAC chips, the same devices that are used in Naim CD players, including the CD555. The processor monitors how fast the RAM (Random Access Memory) buffer is filling up and then selects an appropriate clock rate to prevent any data over- or under-runs.

From this point on things become very complex – unless you relish mathematics and have an in-depth understanding of digital design – so I’ll return to most people’s and my comfort zone. There is a white paper written by the designers, Steve Sells and Hjalmar Nilsson available from Naim’s web site if you want all the unexpurgated information, and if mention of Sallen-Key filters and Monte Carlo analysis pushes your buttons. Hjalmar Nilsson, by the way, is the engineer who recoded the software that powers the SHARC DSP: the device here runs on just five lines of code.

There is a number of ways that one can configure the Naim DAC within the context of a Naim system, which will not always be the place in which it gets used. Indeed, I am certain that Naim would be very happy to see the DAC being employed in other manufacturers’ and mixed systems: I can see no reasons why it should not slot in perfectly well although the openness of its presentation will do no favours to poor quality sources.

I listened to the DAC using a variety of sources but the majority of the auditioning was carried out using a Naim HDX hard disk player and an XPS external power supply, playing through my tri-amped active DBL loudspeakers or through a NAC52/Super-Cap/NAP250 amplifier with NEAT Momentum 4i loudspeakers.  I mention the XPS power supply (£2,850) because it can perform two roles in my system: first it can power the HDX (£4,500) in a no-DAC configuration. When the DAC (£1,950) is added it is best to switch the XPS to powering that and leave the HDX with a simple mains-power connection. The XPS only powers the analogue section in the HDX and that, naturally, becomes redundant when an external DAC is connected. The XPS is best used to bolster the power to the DAC, to which it supplies additional regulated power feeds to various sections providing noticeably enhanced performance.

I began the audition initially by listening to the HDX without its regular XPS2 to establish a baseline performance. Then I added the DAC, and, finally, added the XPS2 to the DAC to gain some appreciation of the benefits the DAC brought to the HDX and subsequently the benefits accrued by including the XPS2. All analogue signals were routed through the DIN connections on the DAC and NAC52 for optimum sound performance using a DIN-to-DIN Chord Company Solstice cable and RCA to BNC-terminated Indigo Plus digital interconnects to connect the HDX and DAC. Naturally, I tried connecting the HDX and DAC with an early sample of Naim’s DC1 Digital cable but comparison with the Chord Company’s Indigo Plus digital showed that the latter sounded distinctly superior in my system and so it remained in place throughout the review. In truth, I felt that Naim’s cable did the DAC no favours at all. Surprisingly, while seeming fine in hi-fi terms, it managed to quash the rhythmic impetus on a favourite Los Lobos track. The Indigo Plus conveyed a far greater sense of the musicians’ vitality and, for example, gave a much clearer indication of when the drummer was ‘pushing’ the beat and trying to spur the band on.  It will be fascinating to repeat the comparison with a final production sample of the DC1.

Listening proper began with rips of Jose Carreras performing Ariel Ramirez’ Misa Criolla, starting with the Kyrie. On just the bare HDX the presentation was excellent but not as spellbinding as a colleague who is familiar with the performance told me it should be. Adding the XPS brought the soundstage into sharper relief and added some depth and substance to Carreras’ splendid tenor voice. Adding the DAC, though, was dramatic to say the least. Carreras came closer to the listeners and his voice gained in terms of detail and expression: not only could I visualize him and the choir behind him much more clearly but the music began to communicate with me far more effectively. The final step was to connect the XPS to the DAC, and the transformation of the performance was astonishing. Stand aside for cliché number one: it was as though a veil between the performers and the listener had been lifted. The hairs on the back of my neck joined those on my arms in standing to attention. Sure, the DAC was digging out far more information and was constructing a three-dimensional acoustic to house the performance like some amphetamine-fuelled mentalist architect, but the biggest leap forward was in terms of the sheer communicative ability. Every element in the mix, especially Carreras’ wonderfully pure upper registers, was making its presence felt and establishing its relevance to the music. The DAC performed real magic with this striking 1987 recording, transforming it from being excellent on the HDX to downright bloody magnificent on the full Monty, HDX/DAC/XPS.

I straightaway realized that there was no turning back: most of my listening was going to be done with this sixth-gear set-up because it appeared to be so vastly superior to the alternative. I had an XPS that had been powering the no-longer-needed analogue stages of my HDX so what was I to do – leave it doing nothing but occupying shelf space or put it to work supplying additional power to the DAC? That question was entirely rhetorical, by the way.

The next album was an old favourite that I had recently ripped to the HDX, Los Lobos’ rather experimental Kiko. The DAC enjoyed this. Greatly, because it gave it so much to work with. The upshot was that after listening to the entire album   – more than once, I have to add – I came away with a completely new-found respect for David Hidalgo and the boys. What truly incredible players they are! Individually they are superb but as a combination… oh boy, can they play up a storm. Their rhythmic cohesion suggests that there is some sort of telepathic communication going on between them. The DAC certainly highlights this aspect of the band’s performance not just because it is especially adept at resolving leading – and trailing – edges but because of its control at the frequency extremes. The DAC is immensely powerful in the bass, so much so that I was feeling many notes through the soft seat cushions of my leather sofa. And SPLs at the listening position were only peaking at about 110dB, so the system was not madly cranked. Despite this the bass was not flabby or blooming but sounded tight and precise. Similarly, at the other end of the spectrum, percussion instruments were brilliantly – quite literally – detailed but not intrusively so. They retained their proper perspective within the proceedings but were portrayed such that anyone who was learning that particular instrument could clearly make out exactly how it was being played. On one track, Angels with Dirty Faces, there is a robust kick drum played throughout and the DAC delighted in portraying the acoustic space around it and the overtones coming off the skin. That is not a big thing in itself but it was an absolute delight to hear, and made me realise just what a remarkable recording this 17-year-old, Mitchell Froom production was.

The DAC had already over-turned my expectations of the improvements it might bring to sources. Past experience with other DACs had led me to anticipate some minor polishing of the presentation and a little cosmetic tidying. The changes the Naim DAC wrought, however, were nowhere near minor: rather they were major-league, fundamental, and substantial. An example of this surfaced on any recording containing pianos, which traditionally are rarely portrayed truly convincingly by hi-fi systems. I listened to Tori Amos play the sparsely arranged Yo George along with other selections from the album American Doll Posse. The sound of the piano had such authority and plausibility that I had to repeat the track to convince myself that I was not falling foul of self-delusion. The juxtaposition of this mighty instrument and Amos’ fragile voice demonstrated the dynamic compass of the DAC and created a magical atmosphere. I’m not talking here about dynamics in the conventional, contrast-between-soft-and-loud-playing sense but in terms of the Naim DAC’s ability to render and gradate delicate playing and note decays. One listener who heard this effect remarked that the DAC had striking ‘downward dynamics’, a term I promptly decided to steal because I prefer it to what others call micro-dynamics.

Comparatively busier mixes such as Que Onda Guero, Girl, and Scarecrow from Beck’s album Guero reinforced the innate ability of the DAC to combine hi-fi detailing with outstanding musical fluency. While it finely etched instrumental timbre and the detail of ‘noises off’ it never allowed these hi-fi considerations to interfere with the musical flow and cogency. The way it portrayed the generous, tuneful bass-line, and the biting percussion and angular guitar leading edges on Black Tambourine, for example, was distinctly impressive but never disrupted the overall musical energy and flow. For instance, I found that I could not stand or sit still whenever Scarecrow was playing, even if I consciously tried: the insistent bass and drums would not permit my limbs not to move.

Nonetheless, it remained the DAC’s characteristic, atmospheric, and utterly winning portrayal of piano that amazed and delighted me, and kept drawing me back to recordings such as Keith Jarrett’s seminal Köhl Concert. I have never been a great fan of his work – or that of any other pianist, in truth – but the spell-binding way the DAC delivered the recording won me over completely. Again it was a dynamic consideration, the DAC managing to display Jarrett’s full range of improvisational expression along with the range of tonal colour he extracted from the rather sub-standard instrument he played on this famous and popular recording.

I began to wind down the session with Pay & Pay from the sublime Renata Youngblood album The Side Effects of Owning Skin, which, because of its sparse arrangements and production, delivered an “audiophile disc”-style performance with all the hallmark criteria of near holographic imagery, separation, clarity and suchlike present. All that was missing was the tedium and ennui. The DAC delivered all the hi-fi ephemera but also dug deep into the music and clearly revealed the subtleties in the outwardly straightforward playing that make the music as persuasive as it is, such as her drummer’s choice of simple transitions and fills, and Youngblood’s delightful phrasing – on both her vocals and guitar.

Having trawled through the classical, jazz and rock genres there was only one left with which to test the DAC: well, two in truth – country and western. So There’s a Tear in my Beer was summoned from the The The album Hanky Panky, Matt Johnson’s homage to Hank Williams on which he interprets 11 of Williams’ songs. It is a live in the studio recording and that immediacy and rawness – and the vital sense of human involvement – emerged especially powerfully through the DAC. Instrumental and vocal timbre also came across convincingly: Johnson’s resonator guitar sounded particularly vivid, and the warmth of the harmonium on Six More Miles brought memories – and with them a tear to the eye – to one happy visitor. Remembering there was a Kenny Rogers cut on The Ecleftic, that we thought might be amusing and, as we were in this C&W mood, we called that album up. Somehow, though, I wound up selecting the Wyclef Jean version of Wish You Were Here, to which I had not listened for ages. I had forgotten that the track featured a massive hip-hop bass-line and wound up the volume so that I could better appreciate the delicate acoustic guitar intro. To say that when the bass entered I nearly raised an eyebrow would not be any exaggeration: it was around 15dB up on the background level and the impact was about as subtle as being thrown down a flight of stairs. Despite this the sound remained composed and well controlled with no sense of strain or harshness becoming evident. It was simply loud. Extremely loud.

Listening to music through the Naim DAC proved it could be both an educational and a visceral  experience: not only does it reveal exactly what is being played but it also strongly suggests why the performer played it that way. It is a facility that is infrequently encountered with DACs – or, indeed, any other components. Little hi-fi displays such genuine true musical empathy. Even less understands that there is so much more to creating a satisfying performance than simply putting the right notes in the correct order. It takes far more than that to allow a listener to forge an emotional connection with a recording… and whatever that ‘more’ element is, the Naim DAC has it in spades.

The departure of the review Naim DAC was a harrowing experience and I am finding the wait for my own sample to be manufactured and delivered seemingly interminable.  I only hope that those in front of me in the queue appreciate just how very fortunate they are.


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