It was as long ago as November 2001 that I reviewed Chord’s DAC64 – forerunner to the QBC76 HD. It made a profound impression. After hearing it, I finally felt CD had come of age. Prior to the DAC64, it was as though CD had a ‘glass ceiling’ that limited it, sonically.
For me, the DAC64 represented a turning point. What made it special? In a word, the WTA (Watts’ Transient-Aligned) filter with 1,080 Taps, and a buffering circuit that reduced jitter. The result was a clarity and holographic dimensionality rarely achieved with CD.
Chord’s QBD76 replaced the DAC64 in 2008. The QBD76 extended the number of filter Taps from 1,080 to 14,832 using 18 separate DSP cores. It also offered compatibility with high resolution digital sources - up to 24bit/192kHz PCM, and an improved power supply.
The QBC76 was also usable with Bluetooth devices, and offered dual DAC inputs to suit Chord’s Blu CD transport. It sounded better than the DAC- 64, in much the same way the DAC64 had improved on its peers. A USB input was also offered.
Back in 2001, those choosing a DAC64 would have bought it to partner an existing CD player or transport. It was a means of improving the sound of your CD player, simple as that. The QBD76 essentially offered more of the same; better sound, and added versatility.
The QBD76 HD carries on this tradition, and allows users to experience an even wider range of sources. The Bluetooth option has been sacrificed, but in its place there’s an HD USB input with the option to decode DSD material using a special chip set.
As most of you will know, SACD playback is not possible with a transport and separate outboard DAC – a prime example of the industry shooting itself in the foot due to record company paranoia over home copying. So the QBD76 HDSD cannot be used for SACD playback.
But it can work with DSD recordings downloaded from internet sources. At the time of writing, this is very much in its infancy. But a number of small Jazz and Classical labels now have DSD material available to download, and the QBD76 HDSD can take advantage of this.
Of course, Red Book CD remains the dominant medium in terms of music available, and the QBD76 HD maximises the results possible from regular compact disc. It’s also outstandingly good when asked to play CDs ripped to a computer hard-drive through its USB connection.
Via the four-second buffer, the sound has excellent clarity and purity, offering a big, solid Presence that’s powerful and dynamic. The QBD76HD makes the most of 16bit 44.1kHz CD, and disguises its limitations with a panache that borders on alchemy.
But it’s with hi-rez material that Chord’s new DAC really comes into its own. While the QBD76 HD gets close to turning the base metal of CD into gold, there’s no denying the extra naturalness and refinement of the real thing. It’s something unmistakeable.
CD’s slight tonal hardness vanishes, being replaced by an easy effortless open clarity. Playing the 24bit/96kHz Dunedain Ensemble’s recording of Handel’s Messiah on Linn Records, the sound had a beautifully sweet yet crisp incisive quality that was impressively natural.
But even this yields to ‘proper’ DSD material. Again, the sound is even more relaxed and natural, yet at the same time very incisive and effortlessly detailed. It was almost too good; spoiling your enjoyment of CD because it is so patently lacking in these special qualities!
On a recording featuring a classical string orchestral, I was taken by the combination of immediacy and effortless transparency. The string tone sounded burnished and rich. It was sharp and immediate without being bright or harsh. In other words, it sounded real.
I used J Rivers Media (a chargeable computer programme that can be downloaded) to play DSD material, and the results were very alluring. In terms of purity and sheer unexaggerated naturalness, good DSD downloads seem to be in a sonic class of their own.
The downside? Limited availability of titles, and the large size of DSD files are the main drawbacks. Even with a fairly big hard drive, you’ll probably run out of space fairly quickly with only a moderately-sized music collection.
Of course, hard drives are getting bigger and cheaper all the time. So while large file size is a consideration, it isn’t necessarily a deal-breaker. The restricted choice of music is more of a concern, but there’s a good choice of classical and jazz from certain specialist labels.
Of course it’s perfectly possible to play music encoded in lower-rez formats to fill in the gaps. But there’s a danger that exposure to higher-rez material will leave you dissatisfied with the sound produced by bog-standard 16bit 44.1kHz Red Book CD.
By virtue of its superior digital processing abilities, the QBD76HD definitely enables formats like CD to punch above their weight. But it cannot work miracles, and inevitably there’s a gap between 16bit 44.1kHz stuff and higher-rez material.
The QBD76 HD offers a choice of balanced and unbalanced fixed analogue outputs that deliver around 6V and 3V respectively. This is higher- than-average, and helps foster the impression of a ‘big’ powerful full-bodied sort of musical presentation.
I’ve already alluded to the built-in digital buffer. It improves clarity and cleanness by lowering jitter. The buffering time is selectable by the user, and can be either one second or four seconds. In most situations, the full four second buffer delivers best results, sonically.
But do experiment with the one second and ‘off’ options before deciding, as there are circumstances where having minimal or no buffering sounds better. When set to maximum, the sound is delayed by around four seconds, which can be a bit disconcerting at first.
In typical Chord fashion, the various input/output sockets and controls are not marked regarding what they are or do. This can be confusing. It would also be helpful, for example, to have some indication as to whether or not the QBD76 HDSD is receiving a true DSD signal.
Agreed, the display indicates sampling frequency. But, it sometimes showed 192kHz when I knew the native sampling frequency was actually 44.1kHz. Clearly, some kind of up-sampling had taken place. It’s easy to be fooled into thinking you’re listening to hi-rez when you’re not.
Build quality is everything you’d expect from a Chord product. The QBD76 HD is very solidly made from aluminium, and beautifully finished. The review sample came in silver and had a brushed finish, but black is also available.
The glass portals are a striking design feature, allowing users to see the circuit boards. The internal lighting changes as you select different options – another attractive feature. During use, the unit gets moderately warm to the touch, but not hot.
Those owning the earlier QBD76 may be tempted to upgrade. However, unless you intend to exploit the QBD76 HDSD’s DSD capabilities, there’s not really much point. Via CD and USB sources, the two DACs sound virtually indistinguishable.
In many ways, the QBD76HDSD is a product ahead of its time. As increasing amounts of high-rez material become available, it will come more and more into its own. It’s a terrific component that must be auditioned by those interested in state-of- the-art digital playback.
Digital inputs: 2x S/PDIF BNC coax, 2x AES/EBU, 2x TOSlink, 1x USB (B-type, 44- 48kHz), 1x USB (A-type, 192kHz)
Analogue outputs: 2x phono, 2x XLR
Dimensions (WxHxD): 33.8x6x14.5cm
Manufactured by: Chord Electronics
Tel: +44(0)1622 721444