December 2012


Chord Electronics Chordette QuteHD DAC
An aural bounty of Chord's superb digital technology at an affordable price.
Review By Phil Gold

  When you think of DAC technology, is Chord Electronics the first company that comes to mind? Well if you read my review of the Chord QBD76 it might well be. This exquisitely designed component, derived from the extraordinary Red Reference CD Player, performed to a remarkably high standard in my 2009 test. The conclusion: "I can assure you the Chord is fully up to the challenge of getting the best out of Red Book and Bluetooth, and exceptional performance from a true high resolution source."

So when the opportunity came to see what Chord has been up to more recently, I jumped at it. I was given the choice of the latest iteration of the QBD76 (now the QBD76 HDSD) or a much less expensive derivative, the QuteHD. I picked the latter since it has not been reviewed yet in North America, and it is likely to sell in much greater numbers.

Tech Time
The QuteHD is a simpler animal than the QBD76 I reviewed. Gone is the Bluetooth audio streaming, along with balanced inputs and outputs and controls of any kind. We are left with a smaller, simpler box, that unique porthole, an exquisite silver finish to match the other components and accessories in the Chordette range, and the secret sauce of Chord's unique digital signal processing technology. A simplified outboard power supply is incorporated into the AC plug. The QuteHD sells for just $1795 and as you will see, it sounds amazing.

Let us take a closer look at the secret sauce. Chord does not buy its DAC chips off the peg. Instead it implements conversion on its own custom Xilinx Field Programmable Gate Array (FPGA) chips. Not just conversion – digital receivers for each input, automatic input switching, clocking, Isochronous USB timing and digital Phase Lock Looping, WTA interpolation filtering, DSD over USB support in addition to Chord's own Pulse Array digital to analog conversion.

WTA stands for Watts (after Chord's Robert Watts) Transient Aligned. The WTA interpolation filtering is a digital processing algorithm developed at Chord to preserve all the important transient information in the original signal while removing all the spurious information that signal contains. In Chord's highly successful DAC64, the predecessor to the QBD76, they used a tap length of 1024 taps to implement the WTA filter, while the QBD76 extended this to an amazing 18,432 taps using 18 separate DSP cores, allowing a greater sophistication in the implementation with resulting audible benefits. The Qute HD uses 10 parallel DSP custom-designed gate level cores to give a third-generation WTA filter of 10,240 taps.

The Pulse Array DAC in the QuteHD is a fifth generation implementation of Watt's delta/sigma DAC, implemented in a simpler fashion than earlier Pulse Array DACs using just 4 elements. Chord claim very high resolution of low level signals, very low sensitivity to jitter, no noise floor modulation, zero anharmonic distortion harmonics and very low harmonic distortion. It also directly handles the DSD signal without the need to convert it to multi-bit.

Chord includes a separate FPGA chip to handle asynchronous USB communication and to isolate the DAC clocks from the computer. Each sample rate clock is generated discretely using highly accurate crystal oscillators for optimum performance and ultra-low jitter performance.

So what's all this about DSD – you can't pass DSD across the S/PDIF inputs can you? No, but the QuteHD, along with big brother QBD76 HDSD and the recently reviewed EMM Labs DAC2X are among the first DACs to accept DSD over USB using the new DoP 1.0 protocol. This allows you replay DSD downloads from your computer in a bit perfect mechanism whereby the DSD stream is actually wrapped up into a high resolution PCM carrier for transmission over USB. Note that the signal is not being converted to PCM and converted back inside the DAC – PCM just supplies a wrapper which is attached before transmission and discarded upon arrival. You'll need a compatible music player on your Mac or PC – I used JRiver Media Centre 17 on a Dell notebook, and then you follow the detailed instructions from Chord as to which settings to make (kernel streaming for native playback and DSD support) and which drivers to load. The Chord will then appear as "Chord Asych USB 44.1kHz to 192kHz" in the soundcard.

It is great news that the QuteHD supports DSD in this fashion, and is likely the least expensive component currently available that can do so, but it is also capable of accepting PCM signals of up to 192kHz/24-bits over any of its inputs, and 384kHz/32-bits on its S/PDIF input. That should keep everyone happy for quite a while. Looking at the unit, the first question that comes to mind is how to select which input to play? There are three available – S/PDIF using a BNC Coax connector, TosLink and USB. The answer is you don't. The unit selects for you. USB takes priority over Coax which in turn takes priority over TosLink. And how can you tell what frequency the data stream represents? Well that's where the porthole comes in. The large glass window let's you see part of the beautifully laid out circuitry and LEDs will turn on to illuminate the innards according to the incoming signal: red for Red Book and so on.

Listening Lounge
When it came down to the listening tests it quickly became apparent I would need all my powers of observation and some very high performing components around to partner the QuteHD because it was clearly immensely capable. So out came the sound pressure meters, the Valhalla cables, a truckload of test CDs and reference level recordings and off went the air conditioning and all possible distractions.

I started by using the DAC to bypass the output stage of a Meridian G08 CD player, which emits an 88.2kHz/16bit (upsampled) stream to the QuteHD over a TosLink S/PDIF connection. The unbalanced analog output from the QuteHD fed the EMM Labs Pre2 preamplifier and from there to the ModWright KWA150SE and YG Carmel speakers. I compared this sound to the balanced output of the G08 going directly into the Pre2 and also the reference EMM Labs XDS1's balanced analog output into the Pre2. I achieved precise level matching using white noise measurements and set identical CDs to play in both CD players. Across a wide range of material the ranking order was always XDS1 first, then the QuteHD and then the Meridian's analog output. To outperform the Meridian's inboard DAC is a very significant achievement, since very few DACs that have passed through my hands have achieved this. But what is more impressive is that the G08/QuteHD combo was actually nipping of the heels of the reference XDS1, despite the advantage a balanced configuration might offer. AB testing hardly revealed any differences. To really tell the difference I had to listen to each option for an extended time, to let myself relax deeply into the music and see how the music affected me in a very subjective fashion.

Where the XDS1 has a small edge is in the size and stability of the image and the blackness of the background. In terms of resolution, orchestral color, dynamics and absence of digital fatigue I simply could not tell them apart. This is an absolutely stunning result for the QuteHD, and it also speaks highly of the ability of the G08 to extract all the bits from the disc. Meridian claims a 10 times improvement in the error correcting ability for its CD/DVD-ROM drive over standard CD drive units for this unit. That, and very careful attention to the power supply, may be the key to providing a good stream, but TosLink is not generally regarded as a jitter free delivery mechanism, so either the QuteHD's proprietary RAM buffering must be doing a superb job of de-jittering the signal or its DAC section must be unusually impervious to jitter components. In short the sound through the QuteHD is extremely dynamic and detailed, with accurate color, fast transient response and strong imaging, a full bandwidth sound competitive with top flight CD players from Esoteric, dCS, Accuphase, Meridian and EMM Labs. It's not a sound optimized towards one type of music. It seems equally happy on rock, folk, jazz, pop and classical music of every scale. I simply couldn't find a CD that was too demanding for it, that embarrassed it next to the reference.

That it performs so well with CDs is great to know, but I suspect most people will be suing the QuteHD through its USB input, for streaming music files from their computers. I used a simple Dell notebook computer with a large database of music ripped using a variety of formats and resolutions, including 192kHz/24-bit, 96kHz/24-bit and DSD. Many DACs can handle the very high rez 192kHz/24-bit files, but very few can handle the DSD files, for which you need specific media players' such as the JRiver Media Centre 17 that I used. The high end EMM Labs DAC2X ($15,500) has similar capabilities and with its memory fresh in mind I can tell you how impressive I found the QuteHD. For direct comparison I played the same source material on disc wherever possible through the XDS1.

Again I'm surprised just how close the DSD stream through the QuteHD comes to the XDS1 playing the same SACD and the same file playing through the DAC2X. Yes there are differences, and they are a little easier to discern than the Red Book comparison, but still you have to strain to hear them. The XDS1 beats the QuteHD in terms of its larger and more relaxed image which makes the music flow more naturally and convincingly. The DAC2X takes the DSD stream up another very small notch, but you've got to look at the price tag and the size of the box. Right up against the best there is, this $1795 DAC goes head to head and matches it on most scores, trailing only a little on dimensionality and ease. I never would have thought it.

Enthusiastic Ending
The QuteHD does a great job with PCM high resolution material too, and easily shows how much better a resolution recording can be compared to a Red Book version. For its startling sonic abilities, its compatibility with a wide range of formats and its capability of accepting S/PDIF signals at up to 384kHz/32-bit, not to mention its startlingly original physical design, I am wildly enthusiastic about this DAC, despite all lack of controls and absence of balanced operation and paucity of inputs. Chord has achieved two major marks. It has made a great no-holds-barred DAC in the QBD76 series, and it has managed to pare back the feature set without significantly degrading performance so that you can have much of Chord's superb digital technology at an affordable price. I hope other manufacturers will take careful note of what's happening here and bring more top notch sound to limited budgets.

Specifications
Type: Digital to analog converter
Harmonic Distortion: < -103dB at 1 kHz 24 bit at 44.1 kHz
SNR: > 120dB
Channel Separation: > 125dB at 1 kHz
Dynamic Range: 122dB
Digital Inputs: One each 75 Ohm S/PDIF BNC coax, optical TosLink and USB. 
Sample Frequencies: Up to 384kHz/32-bit over Coax
      Up to 192kB/24-bit over TosLink
      Up to 192kHz/32-bit over USB
DSD streaming over USB
Maximum Output: 3V (unbalanced)
Output Impedance: 75 Ohm
Dimensions: 16cm x 4cm and 7cm
Chassis Material: Solid aluminum – silver or black finish
Weight: 1 lb.
Manufactured: England
Price: $1795

Company Information
Chord Electronics
The Pumphouse
Farleigh Bridge
Farleigh Lane
East Farleigh
Kent, ME16 9NB
England

Voice +44 1622 721444
E-mail: sales@chordelectronics.co.uk 
Website: www.ChordElectronics.co.uk