Chord Electronics Qutest D/A processor

Back in the mid-1990s, I believed that the design of D/A processors was fundamentally a solved problem. The resistor-ladder, multi-bit DAC chips of the 1980s, with their linearity errors, had been replaced by sigma-delta types that had minimal linearity error down to the lowest signal levels. All that remained for the designers of PCM D/A chips was to increase resolution and dynamic range to the theoretical limits, and to improve the mathematical precision of oversampling digital filters to match the performance of the 20- and 24-bit recordings that had just begun to be released.

Twenty-five years later, nothing seems to have been resolved. The world of D/A processors has split into multiple warring factions. While sigma-delta DAC chips have indeed improved to an extraordinary degree, they are rejected by some hard-core audiophiles for failing to reproduce the force and attack of live music. Conversely, the digital processors featuring resistor-ladder DACs—which, their proponents argue, excel in these areas—can have linearity errors and levels of distortion that raise the eyebrows of conventional audio engineers, especially when those DACs are used without any reconstruction filter (such DACs are usually called "non-oversampling," or "NOS," footnote 1).

And even when the processor uses a digital reconstruction filter, arguments rage about whether that filter should be linear-phase or minimum-phase, and whether it should be short (have a very small number of coefficients or taps) or as long as possible. And that's without considering newer forms of lossless digital conversion. Single-bit DSD encoding, featured in the Super Audio CD medium, came out of left field at the end of 1990s. And even within PCM, there is the MQA format, which rejects Claude Shannon's 1948 thesis that the initial analog/digital conversion should be performed by eliminating all spectral content above half the sample rate, regardless of its level.

I recently spent some time with Aqua Acoustic Quality's Formula xHD, from Italy, which Jason Victor Serinus reviewed in June 2018, and in June 2017 I reviewed the DAVE processor, from British company Chord Electronics. Both are expensive—the DAVE costs $12,488, the Aqua $17,000—and each represents one side of the DAC debate: the Aqua is a NOS resistor-ladder design, while the Chord uses the longest, most complex digital filter available.

As you can read in our December 2018 issue, while I felt the Aqua DAC didn't commit any egregious sins, its sound quality was not totally to my taste (footnote 2). By contrast, Chord's DAVE was one of the best-sounding DACs I've had in my system. I miss it still.

So when Chord Electronics announced a new DAC at a much lower price, the Qutest ($1895), featuring technology trickled down from the DAVE and identical to that used in Chord's Hugo2 ($2395, footnote 3), I didn't need my arm twisted to agree to review it.

Describing
The Qutest is a small, black device wider than it is deep (6.3" vs 2.85") and housed in a case of machined aluminum. A circular glass window in the top panel illuminates to indicate the sample rate of the incoming data: red for 44.1kHz PCM data, through orange, yellow, green, blue, and violet as the sample rate increases to 768kHz; and white for DSD data up to DSD256 encoded as DoP.

Two spherical, polycarbonate buttons are inset in the front panel. The left button selects the reconstruction filter chosen, of which four are available: Incisive Neutral (button illuminates white), Incisive Neutral HF roll-off (green), Warm (orange), and Warm HF roll-off (red). The right button is used to select the source. On the rear panel are four digital inputs: two S/PDIF on BNC jacks (yellow and red button illumination, respectively), one S/PDIF optical on a TosLink jack (green), and a USB port (white). The USB port handles PCM data sampled at up to 768kHz, and DoP-formatted DSD data up to DSD256. No USB driver is needed for Macs; PCs require an ASIO driver, but can send native DSD data up to DSD512 (not that I'm aware of any music files available at that resolution). Unusually, the two coaxial S/PDIF inputs can be operated in parallel to cope with 32-bit PCM data sampled up to 768kHz from Chord Electronics' Blu Mk.2 transport.

1218chordqt.bac.jpg

The Qutest has a single pair of unbalanced analog outputs on RCA jacks. The maximum output level is fixed, but if the Filter and Source buttons are pressed simultaneously when the DAC is powered up, the level can be set to 3V, 2V, or 1V.

The Qutest is powered by an external 5V, 2A supply, this connected by a Micro USB port. The DAC is Chord's proprietary, 10-element Pulse Array Design type, designed by Rob Watts and implemented in a Field Programmable Gate Array (FPGA) chip. The oversampling digital reconstruction filter uses 45 208MHz DSP cores in the FPGA and operates at 16Fs. In keeping with Watts's philosophy (see my 2017 DAVE review for extracts from my interview with him) is very long, with 49,152 taps compared to the typical 128 or thereabouts.

Setting up
I connected one of the USB ports on my Roon Nucleus+ server to the Chord Qutest with a 6' AudioQuest Coffee USB link. After the Roon 1.5 app on my iPad mini had recognized the Qutest, I enabled the DAC as an audio player and set Roon to send it DSD data without first converting it to PCM. I used my Ayre Acoustics C-5xeMP player as a CD transport, sending the Qutest S/PDIF data over an Esperanto coaxial link. (As the Ayre has only an AES/EBU digital output, I pressed into service a Z-Systems RDP-1 digital preamplifier, set to its bypass mode, to act as a format converter.) The only unbalanced interconnects I had that were long enough to reach the amplifiers in use were the 3m Canares I usually use in the test lab. As the Chord lacks a volume control, with the Lamm M1.2 Reference monoblocks I used a homemade passive volume control based on a stereo 10k ohm Alps potentiometer.

Listening
I started my auditioning with the Qutest's Incisive Neutral filter. In my review of Chord's DAVE, I'd commented on the clarity with which it reproduced recorded detail. With the Incisive Neutral filter, I was strongly reminded of that description. In pianist Angela Hewitt's performance of Mozart's Piano Concert in c (16/44.1 ALAC file, Hyperion CA 68049), every instrument in the National Arts Center Orchestra was stably and clearly positioned behind the piano. Perhaps there wasn't quite the soundstage depth that I remember from the DAVE, but that was of minor concern, given the excellent sense of forward motion the Qutest lent to this music. Similarly, with Rachel Podger's performance of Vivaldi's La Stravaganza Concerto 6 in g for violin, strings, and continuo (24/96 FLAC file, Channel Classics CCS SA 19503), the baroque orchestra was unambiguously placed in space, with the theorbo, cello, and harpsichord continuo in the slow movement sounding particularly well-focused.



Footnote 1: See the relevant section of my 2011 Audio Engineering Society lecture here.

Footnote 2: See Herb Reichert's Follow-Up in this issue (p.117).

Footnote 3: See here and here.

COMPANY INFO
Chord Electronics Ltd.
US distributor: Bluebird Music Ltd.
275 Woodward Avenue
Buffalo, NY 14217
(416) 638-8207
ARTICLE CONTENTS

COMMENTS
grussgott's picture

would be great to hear your thoughts compared to the Yggy and RME ADI-2

MZKM's picture

Hi John,

Something I’ve noticed for a while now, but in your wideband spectrum of white noise measurement, Fig. 3 & Fig. 4 in this case, it states -4dBFS, but doesn’t the graph show it at -40dBFS?

John Atkinson's picture
MZKM wrote:
Something I’ve noticed for a while now, but in your wideband spectrum of white noise measurement, Fig. 3 & Fig. 4 in this case, it states -4dBFS, but doesn’t the graph show it at -40dBFS?

In analyses like these, the individual levels of each FFT bin or spectral component are not the same as the signal level. That is equal to the RMS sum of the FFT bins. Each spectral component of the noise signal lies around -40dBFS but together they add up to -4dBFS.

John Atkinson
Editor, Stereophile

Bogolu Haranath's picture

May I suggest reviewing the new Benchmark HPA4 headphone amp/pre-amp? ......... Specs say 256 step volume control and, the head-amp specs also look excellent ......... You could compare it with the passive volume control, you are currently using :-) ...........

John Atkinson's picture
Bogolu Haranath wrote:
May I suggest reviewing the new Benchmark HPA4 headphone amp/pre-amp?

Great suggestion, I'll get on it.

John Atkinson
Editor, Stereophile

Bogolu Haranath's picture

Great ........ Looking forward for the review :-) .........

Bogolu Haranath's picture

May I also suggest reviewing Auralic Polaris? :-) ...........

Integrated amp for the 21st century :-) ............

tonykaz's picture

When one sounds a tad better is it because of the Interconnects?, the difference in Interconnects?, the associated equipment's interface preferences, the physical location of magnetic fields or what???

I've done this same test yielding day to day performance flips. Am I Neurotic? Are all of us Neurotic? My Esoteric Audio Store Ownership experience provided convincing evidence that Audiophiles are a combination of Neurotic & Psychotic behaviors. ( which is probably why families/wives eventually condemn us to the dam Basement ).

Dave Wasserman ( Stereo Exchange ) just did an Audiophiliac Video about his Decades as a Used Equipment Specialist. He reveals the underlying foundation of our audiophile Hobby. It's a Must-See!

Dam it, that Chord Stuff is nice, probably nicer than the PS Audio stuff but PS is one of our few local outfits. We gotta nod to Paul McGowan, don't we?, I sure do! And... we gotta nod to Schiit despite their shitty name, phew, when are they gonna changeover to Stoddard & Moffat? ( isn't S&M naughty enough for them and their youngish, tatted-up customer base?)

We're just around the corner from everything being Class D, no look'n back but there will STILL be the White-Nuckle Grip on Analog from a tiny group tenaciously holding/collecting/hoarding and loving their Fossil Fuel Based, Ozone killing music Format and their Class A Hot Box Electronics, god love em. Harley-Davidson just announced their new Line of Electric Motorcycles ( not made in USA )

Chord is gorgeous stuff, especially if a person lives somewhere in the British Empire, has there ever been a more beautiful Hi-Fi ? It just seems like a person can't go wrong choosing Chord.

Tony in Michigan

Bogolu Haranath's picture

JA can't seem to cut the 'Chord' :-) ............

May be JA could review the new Chord Hugo2 and Hugo TT2 ........ and review the new Meze Empyrean 'phones with the Chords and compare them with his Audeze LCD-X headphones? :-) ............

foxhall's picture

I'm listening to the Angela Hewitt CD right now. Hyperion recordings are often remarkable as you have written numerous times.

tonykaz's picture

I experienced her playing JSBach, she seemed to play effortlessly and seemed to make the playing sound like two Pianos, Phew!

If a person has to live in England and only listens to the near infinite range of Hyperion Recordings they should own a CHORD Music System, it would make rainy days Heavenly. ( even on a 50 foot Narrowboat )

Tony in Michigan

spacehound's picture

Thank you for the review. It's good to see comparisons.
Though Shannon's 1948 work is not a "thesis", it is a theorem, thus as proven as Pythagoras' triangles, and so is not susceptible to dispute or MQA's "rejection".

However:
Having owned several DACs from £100 to £18,000 since I started 'computer' audio in 2010 I have come to a simple conclusion.
I now will NOT purchase any DAC that uses an 'off the shelf' DAC chip such as the various Sabre, Wolfson, etc chips. Not only are such chips purposefully designed to be cheap enough to be used in portable digital radios, TVs, music centres, car audio, etc, they mean the DAC designer is merely implementing other peoples's ideas as best they can, sometime charging thousands of dollars for a box that depends on a five dollar heart.

And the Chords, DCS, and PS Audio ones sound so much better. Also the superiority of even the £400 Chord Mojo over the 'standard chip' sort is instantly obvious on first hearing, though its ergonomics are not best suited to a 'home' system and its battery longevity is suspect.

Were I starting today, from my experience with the Mojo, the Qutest would be my 'go to' DAC regardless of price, even if unheard before purchase.

Mentt's picture

Be aware that Chord DAC sound is not for everybody. Had original Chord Hugo for couple months and sold it. Had Chord qutest for 6 weeks and sold it. To my taste sound was to much sterile and without emotions. Now I am happy with ciunas ISO DAC

spacehound's picture

They can sound a little 'sterile'. But I believe you are hearing Chord's 'accuracy to the source' (which of course is some kind of recording) rather than introduced harmonics and other distortions. And accuracy, not "I personally like it" is what high fidelity means. We don't pay thousands for 'nice'. Though I would like a Kondo Ongaku amp :)

Mentt's picture

For sure it is not about accuracy as Chord DACs have own particular signature = Chord DACs are not neutral

spacehound's picture

That they are as 'neutral' as anyone gets.
However, as we can never know how the recording studio intended any given piece of music to sound, and even they are limited by their equipment, it remains a 'belief' as does yours :)

I'm not qualified to judge their 'pulse array' DAC process but their subsequent 'many taps' (in this case 48,000 rather than a typical 128) filter process makes a lot of sense.

Mentt's picture

You are judging DAC performance based on number of “taps”? Really? Have you even heard the Chord DAC in question?

spacehound's picture

Here's an analogy:
You want to record the length and shape of the UK's coastline.
With only 128 pins to stick in you will get a very inaccurate result. With 48,000 pins you will do it far more accurately.

As I said I am not sufficiently mathematically qualified to judge their 'pulse array' DAC part.

Ears are useless to judge the 'goodness' of this stuff as we have no reference, not being present in the studios when the recordings were made. Ears only tell us whether we like it or not, which has zero to do with high fidelity.
So all we can do is go for a measured flat frequency response of DAC, amp, and speakers and hope. Don't forget the 'time domain' is merely the inverse of the frequency response so a measurement of either one is sufficient.

No I haven't heard the Qutest but I do own a Mojo, a Dave, and a DCS Rossini. They all sound much the same and I assume the Qutest will fall between the Mojo and the Dave. I started with an 'el cheapo' Cambridge Audio Dacmagic. It sounds much livelier than the other three thus initially more involving, but after a while just sounds a mess.

Mentt's picture

Don’t see point of your argument . Either you like the DAC sound signature or you don’t. It is insane to buy DAC for thousands of dollars only because reviewers like it or that it supposedly to be neutral or whatever

spacehound's picture

Just saying where I am coming from. Others can of course come from a different place, it's their money and their enjoyment.

Also don't ever believe that logic is an important 'driver' of human behaviour :)

As for reviewers, in any field, not just hi-fi, they can be a helpful guide as to what is worth following up, though one's actual purchases are your own decision.

Bogolu Haranath's picture

"The pendulum of the mind alternates between sense and nonsense ..... not between right and wrong" ....... Carl Jung :-) .........

w1000i's picture

If the rest of the system is not neutral, the DAC neutrals will not fix that but exposes that.
The best way to jedge DACs is with headphones. You can sawp headphones and they are single drivers with more transparency and less mechanically complicated and without room issues.

Bogolu Haranath's picture

I agree 100% :-) ............

tonykaz's picture

isn't it impossible to agree 100% ?

But, then again, Agent Orrange followers seem to agree 100% with everything he says, lies and all. Hmm.

R you that famous Radiologist my Cardiologist talks about?

Tony in Michigan

Bogolu Haranath's picture

May be, may be not :-) .........

spacehound's picture

...a lack of neutrality in other parts of the system is good.
A lack of neutrality is a fault and you can't fix it by introducing another fault somewhere else.

Bogolu Haranath's picture

So, how many wrong things we have to do to make it right? :-) ............

spacehound's picture

In fact after many years I have come to the point of almost giving up on 'specialist' hifi. As have most sane human beings, as demonstrated by there being less and less dedicated hifi shops.

I have reached a point where I am happy with what I have and unless something breaks and can't be repaired I don't visualise any more significant (= expensive) purchases.

I'm in the UK. Cambridge Audio does well, as does the unrelated Arcam (A R Cambridge). Naim also, at least the less expensive parts of their range. But to 99% of UK 'fairly well-off' households all the rest are very small, Chord included. Meridian sales are so small as to be invisible.

'High Street' names such as Sony, Yamaha, Denon, etc. have become so good with their AV receivers that very few people bother with anything else, except maybe Monitor Audio and B&W speakers, which are available in many UK high street stores. Such receivers used in 'direct' mode are fine for two channel stereo too.

Bogolu Haranath's picture

Check out ATC self-powered loudspeakers .......... Several UK audiophile magazines have reviewed them very favorably ....... One of the 'other' audiophile magazines in USA has favorably reviewed them recently ......... ATC self-powered speaker models are somewhat expensive :-) ...........

Bogolu Haranath's picture

You could also check the self-powered wi-fi capable KEF LS series models ......... also, the new self-powered Elac Navis is another contender ......... The KEF and Navis are not very expensive :-) ..........

If you want to get into 'smart speakers' (which obey your voice commands), you can check the Apple HomePod, Google Home Max and Amazon Echo models ....... The downside is, those (darn) 'smart speakers' will be listening to you all the time, unless you turn them off :-) ............

johnnythunder's picture

is how I characterize CHORD. Very fast. Very clean. Huge power reserves. Leading edge of transients emphasized. Deep bass. Probably great with Orbital played loud in a British flat during a party with glowsticks. Perfect to be played at Hi Fi shows using Clapton's live acoustic Layla. Not for me but I'm like Herb and prefer my audio equipment to have more "meat on the bones." I feel equipment like this is sometimes very exciting to listen to at first but long term has a high fatigue factor.

Sibelius's picture

I am quite sure this DAC sounds very well as all I have heard about Chord's DACs are good comments regarding their sound. Unfortunately, they insist on this industrial design line. To my eyes, they resemble toys, or game consoles.They are not Qute, even less Qutest. I cannot live with what are to my eyes ridiculous looks and therefore this happens to be their main drawback. Of course tastes are tastes and I assume there are thousands of satisfied consumers who approve their controversial design. Moreover, who are willing to pay for them.

spacehound's picture

Chord have an irritating tendency to let their physical design ideas get in the way of their functionality.
I have had a Mojo for about two years and if I want to know the sample rate I still, after all this time, have to look at the box it came in to equate the colour of the button with the sample rate. (44.1 is red and DSD is white though there is no way of telling whether it's DSD64, DSD128, etc. I have to check the box to determine all the others.)
It's even worse with the Qutest, they do the same with the filters too.
I suppose they are trying to be 'clever'. FAIL.

Bogolu Haranath's picture

So, colorblind audiophiles can't use it :-) ...........

Sibelius's picture

Neither functional, then. Also, I really do not get the magnifying glass concept. I would understand a loupe in order to see a machine moving inside, such as in an automatic watch. But I do not think a microchip is interesting enough as to need to see it inside my DAC.

johnnythunder's picture

Skittles.

johnnythunder's picture

I agree. I think their equipment is some of the most ostentatious, misguided, over-complicated industrial design in audio today. To each their own obviously, but the only thing it looks better next to is a Rega Isis style of god know what its supposed to look like style of design. Let me know if I'm leaving something uglier out.

jorgen's picture

tested by John would be very interesting!

Charles E Flynn's picture

“Chord Electronics FPGA DAC Technology Explained” (Video: 5 min. 27 sec.) at https://www.youtube.com/watch?v=hCYUujl1zTM&t=11s .

hollowman's picture

I was just looking thru two early-90s Stereophile issues (Dec. 1992; Mar. 1993) ... not a single analog/phono review or article (tho' I did see an Acoustic Sounds ad with LPs and equip.). Some tube gear. And MANY multibit DACs or CDPs -- reviews, articles, ads, classifieds.
I have a late-1980s aftermarket-modified Philips CDP, with the classic TDA1541A and SAA7220 (4x DF) chipset. It is better sounding than all more-modern DACs in my collection (that feature delta-sigma).
Indeed, those early-90s Stereophiles were full of glowing reviews of Arcams and MSBs and Naims ... all using that classic Philips platform.

I have some non-oversampling (multibit) gear, too. And it has that whatchamacallit sound charc. that appeals to some. Not me. BUT, I'll take well-done NOS over poorly-done DS any day.

My suggestion for JA and other Stereophile reviewers is to go into their attic or basement storage ... and dig out legacy gear. And use THEM as a basis of comparisons against Chord, Border Patrol, Benchmark, etc.

Oh ... JA ... please webify that 1995 Fabio article. He had VERY high-end $$$ system based on a Krell CDP. No phono, no tubes.

spacehound's picture

….the poor ergonomics of some Chord DACs don't matter in actual use, which is listening, not testing.
Take the Qutest filters. Most people will find the one they like best and stick to it. Let's say you find that you like the 'green' one best. Having selected it once, the next time you switch it on it will also be green as it remembers the last setting. Even if you want to try different filters all the time it is not the filter specification that matters, it is whether you like the result or not. And it's just as easy to remember "this sounds most to my liking on the blue filter" as it is to remember the "quick rolloff HF filter".

And as for sample rates, you play what you have, some of which will be 44.1, some 96, or whatever. The only time you actually need to know it is in the initial setup or your player, such as JRiver or Tidal MQA/non-MQA, for example. It's the player and/or the recording that sets the sample rate, not the DAC. Once setup to play the recordings at their 'native' rate (or, for example, if you prefer some upsampling rate) you don't need to know what the rate actually is anymore. You are listening to "Beethoven's Ninth", not "44.1" or "MQA".

tonykaz's picture

What's poor ?

Seems a luxury arrangement to have Color, lights, mystical Spheres and exotic metal packaging.

Would customers pay Premium Prices for something dreadful?

Chord's uniqueness is a Statement, isn't it?

Kinda like an Audiophile tattoo proclaiming something Architectural and Social Level about it's Owner.

It's almost like Chihuly Art Glass Objects.

I have to approve & admire the daring Owners.

Tony in Michigan

johnnythunder's picture

feeling is better than apathy or purely style-less products like Bryston. I actually don't mind the look of the little DACs - quirky as they are. I've been tempted by some of the good reviews but those reviews come from people (usually British) who like the overall Chord "house sound" of clarity and detail. A warm fleshy sound gets me every time and sounds like live music from a great seat in the middle of the orchestra or a back in the balcony where the sound is blended and sometimes diffuse in a good way. Chord, ATC stuff sounds like my head is in the speaker.

hollowman's picture

I've never owned, touched much less heard a Chord product. Nevertheless, I like the overall "Apple-like" product design.
For example, with the form factor of DAVE (and similar DACs going back to 2001), Chord managed to squeeze in all components (incl. a switching PS) into a nice, compact unit. It's not a big, heavy thing like many high-end DACs.

Bogolu Haranath's picture

Chord designs kinda look like the space ship in the Spielberg film 'Close encounters of the third kind' :-) .........

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