FPGA Digital to Analogue Converter (DAC)
The Qutest is the successor to the Chord 2Qute adopting a similarly quirky name which is a trend of some products in the Chord stable. I’ve said before that I think adopting such quirky names risks understating the product but this certainly makes it stand out.
Like the 2Qute, the Qutest looks nothing much at a distance with its simplicity and small box design. As opposed to normal half and full width case HiFi DACs, it would be easy to have reservations about its performance based on case size, if you’ve no experience of Chord products. It’s only when we get up close and personal that we see what it’s all about.
What’s in a small box?
The Qutest is very smartly made with a black aircraft grade aluminium casing, typical glass lens window through which you can look into the electronics, and as with the Chord DAVE, the Chord logo plaque is fitted to the top of the case. It uses 8 black sorbothane rubber feet and unfortunately I found they stained my light wood rack, which isn’t something you’d expect at this price.
It’s heavier than the 2Qute for added stability when all rear sockets are connected up. On this score, you get a USB input which is galvanically isolated, two BNC coaxial digital inputs, and a toslink/optical digital input. There are the usual single ended RCA analogue outputs and the 5volt mains socket to which you use the box supplied ‘wallwart’ power supply. The two BNCs can be connected together in ‘dual data mode’ for use with the Chord Blu mark 2 CD transport, which basically allows the Qutest to receive higher sampling frequencies.
The Qutest uses the same DAC as in the Hugo2 but unlike the Hugo2 doesn’t have any internal battery supply so it’s running direct from the wallwart and it’s always on with no on/off capability. It also shares the same sound filters as the Hugo2, selected by the front button which changes colour accordingly, as with the front input button too. Unlike the Hugo2 it has no headphone socket so with these features it’s clear it’s designed as a stand alone rack based HiFi DAC. There is no Bluetooth connectivity which is no disadvantage since if you are buying a DAC of this quality, there is little point throwing it compressed content.
Chord use FPGA (Field Programmable Gate Array) DAC technology across all their DAC products. In simple terms FPGA is a DAC chip that allows the manufacturer to programme code into it so it can perform as they desire. There are a number of logic gates or ‘taps’ to do so and the technology differs to conventional off the shelf DAC chips which cannot be programmed. In comparison to the 2Qute which has 27,368 taps, the Qutest takes this up to 49,152 with its Xilinx Artix 7 FPGA DAC.
When plugging in the power supply the DAC goes through a start up sequence where the code is programmed into the FPGA. During this time you can change the output gain voltage to either 1v, 2v, or 3v by pressing both top buttons together to achieve the necessary corresponding colour. This is to match input voltage of your preamplifier or integrated amplifier for volume level matching purposes. A little experimentation will achieve the best result here.
An LED inside the case changes colour according to the sample rate frequency of music detected, which is a common feature of Chord designs. If you place the Qutest on top of a rack, light from the LED is refracted by the glass lens onto a wall, to pleasing effect.
The Qutest handles PCM CD quality and high resolution formats from 44.1khz (CD sampling rate) up to 768khz, which is double that of the 2Qute, and in 16 bit (CD) to 32 bit (hi-res formats), so will handle all formats you can send it. As a DSD DAC it deals with up to DSD512 rate files via its USB connection, but converted to PCM (DoP – DSD over PCM). The 2Qute could handle a maximum DSD128 over USB and Coaxial/BNC but the Qutest still offers the same over coaxial/BNC but this can be taken up to 384khz for PCM formats if you use the twin coaxial inputs in dual data mode. You can only play up to DSD512 files natively without any conversion if you hook up the Qutest to a windows based PC or laptop over USB with the correct Chord windows driver installed. As with any optical connected device, it can handle up to 24bit/192khz only. Put this all together and the Qutest is certainly future proofed format wise.
In sound tests I used my PMC twenty5 speakers, Cyrus DAC XP Signature pre amp/DAC with PSX-R power supply, Cyrus Mono X200 signature power amps, Innuos Zenith Mark 2 source into the Qutest over USB, a Cyrus cd-t transport via coaxial/BNC and Chromecast Audio streamer via optical. I also tried the Qutest with Bryston BP173 and Audio Research LS26 preamplifiers.
As DAC comparisons go these were against the DAC’s in my £3000 Cyrus DAC XP Signature, the £1000 2Qute with a MCRU linear PSU as well as the Benchmark DAC3 HGC and Mytek Brooklyn DAC. As a reference I have also had the £8500 Chord DAVE in my system too. I tried the Qutest with its wallwart and a similarly designed MCRU linear PSU for it.
It did take a while of being on before it reached its potential, which I found with the 2Qute too. After a day or so a less flattened more responsive and dynamic sound was on offer.
What is most obvious and noticeable in moving from the 2Qute to the Qutest with or without linear PSU’s connected is an increase in resolution. The same can be said of moving from the other DAC’s. The extra resolution of the Qutest is quite marked if you’ve had the 2Qute in your system for a while. Generally what this DAC does so well is bring incisiveness.
The Qutest also presents as having a nice meaty sound with good bass extension and depth compared to these other DAC’s mentioned. When swapping between the two DACs with their individual MCRU linear power supplies an owner of the 2Qute heard the Qutest on my system and thought improved bass responsiveness was very obvious, as I did too.
The other DACs mentioned seem to achieve their resolution with quite a bit of treble airiness that requires better system matching, however the Qutest is not like this. In this sense it’s very balanced and neutral and it neither adds or detracts from your pre-amplifier or integrated’s tonal qualities, to achieve the sound you have originally matched with speakers, amplifiers and sources. The Qutest will therefore be good at injecting life into old DACs that haven’t been upgraded for a while, or those in digital source components, plus it will fit into lots of systems. This resolution makes the layers in the music more apparent and is clearly to be welcomed. The Qutest’s dynamic capabilities are very good too.
On some music there is a touch of edginess in the treble when using the Qutest with the wallwart and my Cyrus Pre, but this I put down to the Cyrus. With the Bryston or Audio Research Pre and Qutest there is no edginess or harshness or any edgy sibilance in vocals at all. With the addition of the MCRU linear power supply with the Cyrus, good balance was achieved and in this combination the edges were smoothed off somewhat.
Against the 2Qute, the Qutest is more dynamic and immediate in its presentation, and there is a level of authority over its forebear. It’s much nearer to the DAVE in performance and whilst it’s about 1/7th the price, in my view it achieves about 70-80% of the DAVE’s performance which is no mean feat. It doesn’t quite possess the sheer realism of the DAVE and the way it projects detail, particularly in the midrange. However it’s a lot closer than you would think given the price disparity. This is the law of diminishing returns for you. I’d put the Qutest as a good 30-40% improvement on the 2Qute.
The designer Rob Watts has stated that the Qutest only needs be used with the wallwart and that if sound quality isn’t improved with a battery supply, which according to him is its most stable power source, there is no point purchasing a linear PSU. I tried a Sandstrom 5v rechargeable battery supply plugged into the Qutest using its 5v out USB socket, and whilst I initially thought I could hear a change, I decided there is negligible difference. With the MCRU linear PSU it is different and more noticeable and I found a slight but definite lowering of HF graininess with the partnered Cyrus and Audio Research and a lowering of the noise floor. Unfortunately I didn’t get to test the Bryston and Qutest with the MCRU linear PSU, but with the Bryston’s neutrality and refinement I’m not so sure any HF noise in the chain would be as noticeable.
What is noticeable in difference to DACs like the Cyrus, Benchmark and Mytek is how the Chord makes much the same of different sources of differing quality and price. The Chromecast Audio is clearly not as good into the Qutest as the Innuos Zenith is as you’d very much expect, but it was closer than I thought would be the case, and I’d put a large part of this down to how the Qutest handles sources relatively equally.
It’s a DAC which is as much pleased playing Mozart as it is Leftfield or any acoustic or rock music. The digital filters can be used to good subtle effect to further take the edge off some sharp digital recordings. I’ve tended to keep to the incisive neutral filter to hear the full frequency spectrum. Selecting the Incisive neutral HF roll off filter does often help on some Tidal recordings to remove grain. The warm and warm HF roll off filters haven’t been used much as they are more marked and if your system is already quite balanced you are perhaps unlikely to use these. For older recordings with not much body they do sometimes inject a useful helping of warmth I’ve found.
DSD playback is not in the same league as the DAVE DAC using its DSD mode. However some good DSD recordings are noticeably more nuanced with the Qutest than the same PCM CD or hi-res recording playing similarly from my Zenith’s solid state drive. Tonally a bit richer and more natural, particularly the very good DSD128 recording of Dire Straits ‘Brothers in Arms’, and a DSD recording of The Carpenters ‘Singles 1969-81’. This is the case even though this content is being converted to PCM as DoP.
At the same time as the Chord Qutest, I did have a $1350 Border Patrol SE DAC with a coaxial input, but since my Zenith doesn’t have a coaxial output and I was restricted to using my CD transport, meaningful comparisons couldn’t be made to the Qutest over USB with my better Innuos source. It would be interesting to compare a Border Patrol DAC of the USB input variety to make a meaningful comparison though.
If you were ever to look past the Chord Qutest for its size and non conformist design, and dismiss it on that basis, you might very much regret it. For anyone looking for a resolving neutral stand alone DAC around this price, I really think you’d be struggling to find better and it should definitely be on the audition list. It stands out as a superb product, is punching well above its weight, and it’s easily a Best Buy. It achieves the 13th Note!
- Chipset: Chord Electronics custom coded Xilinx Artix 7 (XC7A15T) FPGA
- Tap-length: 49,152
- Pulse array: 10 element pulse array design
- Frequency response: 20Hz – 20kHz +/- 0.2dB
- Output stage: Class A
- THD: <0.0001% 1kHz 3v RMS 300Ω
- THD and noise at 3v RMS: 117dB at 1kHz 300ohms ‘A’ weighted (reference 2.5v)
- Noise 2.6 uV ‘A’ weighted: No measurable noise floor modulation
- Channel separation: 138dB at 1kHz 300Ω
- Driver : Windows only
- Weight: 770g
- Dimensions: 41mm (H) x 160mm (W) x 72mm (D)
- Boxed Weight: 1500g
- £1195 (black only)
- MCRU Qutest Linear Power supply – £235
Chord Electronics Ltd
Tel (01622) 721444