Chord Electronics DAVE D/A processor Page 2

Watts again: "Bob Cordell proposed nested feedback loops in the 1980s as a way of improving amplifier performance. . . . [W]hat he was proposing was equivalent to a second-order analog noise shaper [that] eliminates distortion. There is a huge amount of negative feedback available with a nested feedback stage, even at 20kHz. The benefit is that when you plug in a 33 ohm load, there is no increase in distortion at all. In all my DACs I've got a very simple analog structure. From Mojo right up to DAVE, it comes down to two resistors and two capacitors and a single amplification stage . . . which gives us much greater transparency. There is also a digital DC servo in the circuit, so there's no coupling capacitor: the error signal is fed to an A/D converter and cleaned up, before being used to eliminate DC at the output."

Setup and Use
The DAVE's display has four zones: the top half displays the selected input, sample rate, and volume level; in Display modes 1, 3, and 4, the background color reflects the rate and volume (Display mode 2 is black and white). The middle two sections of the screen show the setup options: PCM/DSD, Phase (Polarity), HF Filter on/off, and Display mode. The bottom section shows whether the Chord is set to DAC mode (fixed output), Digital Preamplifier mode (volume control active), or Headphone mode (plugging headphones into the front-panel jack mutes the main outputs).

As I was going to use Chord's DAVE without a preamp in the system, I used its button array to set it to Digital Pre mode by scrolling down the displayed options until the operating mode was highlighted, then pressing the left and right buttons simultaneously. The big central button then acts as a volume control; pressing it mutes the output. Inputs are selected by pushing the left and right buttons. If both these buttons are pressed simultaneously while the D/A mode is highlighted, the user can select the PCM Plus or DSD Plus filter. (The Chord mutes for 20 seconds after either is selected, while the circuitry stabilizes.) The top-panel controls are duplicated on the remote control, but as this has buttons to control other Chord products, it's way more complicated than it needs to be.

I had one operational glitch with the DAVE: the bodies of the connectors on my TosLink cables were too big to allow them to be locked in place when plugged into the rear panel, though the input did lock on to optical S/PDIF datastreams.

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Sonics
The DAVE arrived in my system while I was preparing the CD masters for Stereophile's Tight Lines project, a collection of Sasha Matson's compositions for chamber ensemble. I was trying out different dithering algorithms to reduce the 32 bits of the master files to the 16 necessary for the CD release, and with the DAVE turning the digital bits to analog waves, I could arrive at the optimal dither relatively quickly.

Although Tight Lines was recorded with multiple mikes in a Hollywood scoring studio, engineer Michael C. Ross had captured good soundstage depth, and his work was readily evident through the DAVE. There was again superb soundstage depth with a favorite orchestral recording, Charles Dutoit's performance with the Montreal Symphony Orchestra of Mendelssohn's A Midsummer Night's Dream (16/44.1 ALAC files ripped from CD, Decca 417-541-2). The woodwinds in particular—in the Scherzo, for example—were each set well behind the plane of the speakers.

Tasmanian reader John Coulson recently e-mailed to say how much he had enjoyed Stereophile's Encore, a selection of chamber works by Brahms and Mendelssohn that I'd recorded live at the Santa Fe Chamber Music Festival in 1997 (CD, Stereophile STPH011-2). I hadn't listened to this album in a couple of years, so I selected the 16/44.1 files in Pure Music on my Mac mini and pressed Play while I sat at my desk, working on some copy. Darned if I didn't have to go sit in the listening chair, so compelling was the sound produced by the DAVE. I hadn't remembered there being so much depth to the soundstage, or the instruments being so securely rooted in the acoustic of the St. Francis Auditorium. Marji Danilow's appropriately gruff-sounding double bass provided a solid foundation to the music making, and pianist Christopher O'Riley sets some fast tempi in the finale of the Mendelssohn Sextet that make other recorded performances seem very staid.

The DAVE did indeed do well with piano. O'Riley's notes were very well defined, placing the instrument solidly between and behind the speakers. I switched from Pure Music to the Tidal desktop app and called up Daniel Barenboim's recent solo recording of Liszt's arrangement of Solemn March to the Holy Grail, from Wagner's Parsifal, from On My New Piano (16/44.1 Tidal HiFi stream, Deutsche Grammophon 289 479 6724). The deep tolling bass notes of Barenboim's unique straight-strung piano sounded majestic with the DAVE in the system. On to CD, with my Ayre Acoustics C-5xeMP feeding the DAVE AES/EBU data: Evelina Vorontsova's hauntingly beautiful performance of Rachmaninoff's Piano Sonata 2 sounded rich, detailed, and yes, again, majestic (CD, STH Quality Classics 1416092). The DAVE is the DAC for lovers of recorded piano.

I've mentioned recordings of orchestral and chamber music and solo piano; what about rock? Before leaving for last January's Consumer Electronics Show, I used the Vinyl Studio app with Ayre's awesome QA-9 A/D converter to rip some 12" 45rpm singles to 24/192 AIFF files, including Joe Walsh's "Rocky Mountain Way" (ABC ABE 12002), which has probably the most dynamically recorded drum sound ever. Back home, after having stretched the dynamic-range envelopes of several systems at CES almost to their breaking points—as I wrote in these pages years ago, you just can't play "Rocky Mountain Way" at anything less than head-banging SPLs—I played the track with the DAVE feeding the monstrously powerful MBL Corona C15 monoblocks driving Rockport Technologies Avior II speakers. Heads were banged, walls were shook, feet were set a-dancing—the DAVE delivered the dynamic goods!

Comparisons
The obvious comparison was with Meridian's Ultra DAC ($23,000), which I reviewed in the May issue. The Meridian offers MQA decoding, the Chord doesn't; so to somewhat level the playing field, I used the latest version of the Tidal app (2.1.5) on my Mac mini with the MQA Passthrough button unchecked (this allows Tidal to perform the first unfolding of MQA files), feeding 2Fs data to the DAC. With Tor Espen Aspaas's performance of Beethoven's Piano Sonata 32 in c, Op.111, from Mirror Canon (Tidal Master stream, 2L 2L-049-SACD), the 44.1kHz-sampled data were unfolded to an 88.2kHz stream, according to the DAVE's display. Even without MQA decoding, the sound of the piano was reproduced with superb force in the lower registers. Aspaas takes the second movement's stately opening Adagio slower than I'm used to, but what erstwhile Stereophile columnist John Marks described as Aspaas's "wonderfully poetic playing" was extraordinarily compelling.

I rechecked the MQA Passthrough button, to send the 24/44.1 MQA stream to the Meridian to let it perform all the MQA unfolding. Its display read "352k," and I set the playback level to be the same as with the DAVE. Superficially, the sound with the Ultra DAC was identical to that with the DAVE: same pianist, same piano, same hall. But after a while, I became just a little bit more aware of how the harmonic envelope of a note changed as it died; the pianist's touch on the keys was just a little more developed with the Meridian fully decoding the MQA data. Yes, this was a subtle difference, but not an unimportant one in the context of DACs costing five figures.

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For a fairer comparison, I tried both DACs with DSD files sourced from the Aurender N10 music server via USB, specifically violinist Christian Tetzlaff's performances of the third Brahms sonata, accompanied by pianist Lars Vogt (DSD128 files from HDtracks, Ondine ODE12842), and set the DAVE to its DSD Plus mode. With the DAVE decoding the bits, both instruments were presented with precise stereo imaging, natural-sounding tonalities, and with the piano's left-hand register offering the weight I'd noted earlier with PCM files. Perhaps the violin didn't have the quite the seamless top end I was expecting from my earlier listening, but this was still a first-rate presentation of this emotionally charged music.

Switching to the Meridian with levels matched, the sound was warmer, with less weight to the piano's bass notes but a slightly mellower violin. Given my druthers, I'd combine the Chord's piano reproduction with the Meridian's violin tone.

Conclusions
I very much enjoyed the time I spent with Chord Electronics' DAVE. Its superb re-creation of soundstage depth, its sense of musical drive, and the clarity with which it presented recorded detail were addictive, though that clarity did demand that ancillary components be equally high performing. And the DAVE's price is considerably lower than that of the high-achieving DACs from Meridian and dCS that I have reviewed.

There are two unanswered questions, however. One is practical, in that as systems increasingly become network-based, the DAVE's lack of an Ethernet port might eventually become a limitation. The other concerns MQA. If that format gains in acceptance, then the DAVE will never be able to get the best from it: MQA's and Rob Watts's ideas on filter design are incompatible.

Which leads me to a final point: As much as I was impressed by the DAVE, my experience left me puzzled. In recent years I have become convinced that the best sound from digital in general is to be gotten from DACs that use very short reconstruction filters: Ayre Acoustics' Listen filter, for example, and the equally short filter used by MQA decoders. And I've found that minimum-phase filters, as used by dCS and Meridian processors as well as by Ayre, tend to sound more natural than the usual linear-phase filters.

But here I am, recommending a DAC with a linear-phase FIR filter that is not merely long but the extreme opposite of short. What gives? To stretch an analogy: If perfect sound quality lies on the other side of a mountain of implementation, the short, minimum-phase filter route goes one way around that mountain, and the long, linear-phase filter route goes the other way. But on the far side of the mountain, the two routes begin to converge . . .

All I can say is that you must listen to the DAVE for yourself.

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

COMMENTS
Anton's picture

Any comment on how it performs as a PS4 controller?

tonykaz's picture

What will come of these DAC designs as MQA gains even more Gravity?

Already we have respected folks like Hans Beekhuyzen, JA and Mastering Engineers ( like Bob Ludwig ) explaining the Future Benefits.

Mr. Ludwig says that MQA removes Pre-Ringing, whew, that alone makes it worthwhile, doesn't it?

Perhaps ( reluctantly ) we say 'by-by' to Multi-bit, R2R, FGPA and any another design not adaptable. ( Schiit YGGY obsolete?, certainly! )

It feels like Digital was refined, than more refined, then refined yet again. phew.

There are only a few 'remnant' that still cling to vinyl as their primary music storage system, it just seems so awkward and cumbersome. Why would a new music lover want Vinyl expense and square footage demands?, especially since MQA Dac prices start at $200!

Right now, today, I'm figuring that everyone in the Audio Business wants to be Bob Stuart.

Tony in Michigan

Archimago's picture

Hey Tony... I trust that was said with tongue firmly superglued to cheek :-).

I'm not sure if most want to be Mr. Stuart. I'm sure the company must have spent a pretty penny on MQA marketing over the years just from the business perspective.

tonykaz's picture

There is a Team of Software Developers behind all this, Stuart is their Managing Director who's flying around the World selling the Project.

It seems like everyone is getting On-Board.

Betcha it's exciting to be a part it.

Right now, everywhere there's an Audio Group gathering, Stuart is their No.1 choice for Keynote Speaker. Sort-of like he's the Steve Jobs of Audio.

Tony in Michigan

ps. this is my estimation, I've always like Meridian designs, I've been one of their dealers.

Anton's picture

I use MQA for streaming, it's fine.

I don't get the evangelical response it has received in certain corners. It's like someone told a tale of finding some golden ears in a secret place hidden by an audio angel and created the "Book of MQA" and the cult took off from there.

tonykaz's picture

Wonderful analogy, wish I'd of thought of it.

But

Meridian has always been an Engineering Company ( like 3M Corp. ), they've been at the forefront of Digital advancement. I've know these guys since the early 1980s, they're a no-bullshi... type group.

I don't think that I 'believe' in Meridian or MQA but rather I trust Meridian and MQA. The down-side being that they are upper-middle class. Still, a person can access MQA with a $200 Explorer2, $300 for an Audioquest Dragonfly RED or go full desktop with a Mytek for $2,000. ( we can't and won't be able to get a Schiit Bifrost MQA, too bad, I'm a Schiit fanboy )

I don't expect greatness from MQA, just advancement.

I hope we're not boxing ourselves into another corner.

Tony in Michigan

Anton's picture

This ----> "I hope we're not boxing ourselves into another corner."

tonykaz's picture

Ortofon sent their Man to Analog Planet Headquarters to show their New & Improved $4,000 Phono Cartridge, the video is now on YouTube. Please notice the vastness of the Vinyl Record Collection used as the Backdrop, it's gigantic ! Vinyl guys are boxed into storage of Vinyl and the Fragile nature of the Gear needed for playback, not to mention the total lack of portability & incredible expense.

CD is copyable so it's profit possibility for Artists is less ( perhaps considerably less )

MQA/Tidal is Global in nature, as the World adopts Streaming, new issues will manifest themselves. Will this become another limiting factor?

My hope is to have access to all the recorded music that's out there, on a rental basis. I don't want to rely on my own digital storage & hard copy storage systems.

If I dump my vast CD collection and abandon my hard drive storage systems to rely on Tidal's rental collection will I be boxed in and risk Tidal going out of business? ( and ever increasing Monthly usage charges ).

Seems like there's always something to be worried about, like getting the Big C.

Tony in Michigan

hollowman's picture

Chord's view -- "going for broke" on no. of taps to use in their devices -- is interesting.
Only a few weeks ago, Stereophile had a YouTube video interview with heads of mbl (German company). I think they said tap qty was more of an art and science -- a Goldilocks approach. If you go too high (as far as mbl was concerned) you can start harming the sound.

Staxguy's picture

Any chance Chord Electronics will be so kind as to send you their Blue 2 CD to add to the equation?

AllanMarcus's picture

"implying resolution close to 20 bits, which is state-of-the-art DAC performance"

I thought 20-bit was obsolete? Stereophile said so on their Facebook page.

John Atkinson's picture
AllanMarcus wrote:
John Atkinson wrote:
implying resolution close to 20 bits, which is state-of-the-art DAC performance
I thought 20-bit was obsolete? Stereophile said so on their Facebook page.

20-bit chips are obsolete as they become the limiting factor in resolution when used in real-word audio circuits, ending up with <20-bit resolution. The very best current D/A processors achieve between 20 and 21-bit resolution, limited primarily by the thermal noise of the resistors used.

John Atkinson
Editor, Stereophile

dmusoke's picture

Are these resistors internal to the DAC or external in the post dac filtering circuitry?

John Atkinson's picture
All resistors produce thermal noise. The noise can be reduced by using lower-value resistors and correspondingly higher currents, but there is a practical limit.

One point I neglected to make in my earlier posting that in the specific example of a D/A processor using 20-bit DAC chips, that product's, in my opinion, less-than-optimal way of reducing the bit depth from 24 to 20 would result in a noise floor that would correlated with the signal. This is potentially more audible than a constant level of noise.

John Atkinson
Editor, Stereophile

dmusoke's picture

Yeah, if they had used, say, an ESS9038PRO dac, the performance would have just as good, if not better with its huge 140dB dynamic range.

The DAVEs IMD spec is indeed excellent. But you have tested other expensive dacs here with superb specs similar to this one. So how does the DAVE sonically compare with these other dacs, some using traditional dac chips?

Maxx134's picture

If you say, "The very best D/A processors achieve between 20-21 bit resolution..."
And you state the Dave achieve "close to" this, and yet in Yggdrasil you make no mention of this,
How useful is all this work testing if this info is not laid out for the readers?
Why do I have to read the comments to realize these details?

So I have to "read between the lines", that the Dave get close, and the yggy is in league with "The very best D/A achieve between 20and 21 bit resolution"....

You focus on noise quite a bit..
To me, noise is not the issue.

The issue is that I have heard many top end dacs with a very unnatural quiet black background which I KNOW is not true to the source.
These dacs remove the background while cleaning up the noise floor, thus loosing information.

I would look again into some noise floor aspect to find out why.

So far, the Dave IMHO produce one of the most beautiful music I ever heard, as I hear no flaws in the source,
While the Yggdrasil still shows me the flaws in the source, with a slightly larger soundstag,
again IMHO.
Edit :
I just realized the effects described of black background are rom lower bit resolution (!)

ultrabike's picture

This may be an oversight or my lack of understanding. But if you notice, the -90 dBFS 16-bit tone plot has a 1.5 mV peak-to-peak range. This seems unusually high relative to other plots I've seen here.

That seems to imply that 0 dBFS is about 33.5 Vrms or so. Doesn't this DAC clip at 12.35 Vrms? (assuming 8.75V is rms and "+3dB" mode is therefore 12.35 Vrms)

Wouldn't that create the illusion of more effective number of bits because the 0 dBFS signal power is much higher, relative to noise floor, than when referenced to a perhaps more standard 2.0 or 4.0 Vrms? I say illusion because of clipping, and because not many downstream equipment (for example, an amplifier) may accept a 33.5 Vrms range with out any issues.

By similar arguments, wouldn't a 1.5 mV peak-to-peak -90 dBFS plot seem visually less noisy when compared to a say 0.2 mV peak-to-peak -90 dBFS plot?

John Atkinson's picture
ultrabike wrote:
This may be an oversight or my lack of understanding. But if you notice, the -90 dBFS 16-bit tone plot has a 1.5 mV peak-to-peak range. This seems unusually high relative to other plots I've seen here.

Yes it is. I set the Chord's volume control to its maximum for this test, even though that would have resulted in clipping with a full-scale signal, because I couldn't replicate the manufacturer's own measurement at lower levels.

ultrabike wrote:
Wouldn't that create the illusion of more effective number of bits because the 0 dBFS signal power is much higher, relative to noise floor, than when referenced to a perhaps more standard 2.0 or 4.0 Vrms?

With this test I was more concerned with looking at waveform symmetry with the undithered data.

John Atkinson
Editor, Stereophile

rhgg2's picture

I am slightly confused. On the one hand you say:

Quote:

With this test I was more concerned with looking at waveform symmetry with the undithered data.

i.e., the fact that I boosted the volume to impracticable levels is not relevant to the test results. On the other hand you say:

Quote:

I set the Chord's volume control to its maximum for this test, even though that would have resulted in clipping with a full-scale signal, because I couldn't replicate the manufacturer's own measurement at lower levels.

i.e., the fact that I boosted the volume to impracticable levels is critical to the test results, as it is only by so doing that I can avoid the conclusion that the manufacturer's claims are spurious. I am reminded of a well known expression involving the eating of cake.

Could I suggest that you provide the results at a standardised level that does not clip the full scale output, so as to allow a fair comparison with other products you have objectively tested?

Maxx134's picture

For the yggydrasil review, you measured similar test waveform of undithered 1kHz sinewave...
yet at 24-bit data, and at extremely small levels of 200uV peak to peak!.
Then with Dave you change your test parameters because you cant get a good "manufacturer" result???!

This leads to pics that are thus misleading for the Dave, in comparison to all other Dacs reviews.

I rather to see a uniformity in your testing to be able to get a true comparison to other dacs, especially the yggydrasil.

As it stands member "ultrabike" sheds light to this discrepancy in measuring uniformity.

Therefore I would like to know, if you cannot achieve the performance the manufacturer states for the Dave,
What were your initial findings before you decided to "juiced up" the settings?

I already heard the Dave personally and have commented positive about it, so not knocking it, but, in fairness..
Curious members want to know.

arashid026's picture

I've read all the reviews of the new Chord DACs, and for some reason I feel the team at stereophile doesn't bring up the key reason of the TAPs and the USP of Chord. These DACS all have the fluidity and gentleness of true analog, but this is never mentioned. If you check the review of even the QBD76 on what hi-fi they did identify this very desirable quality. When I play Metallica on Vinyl, and then hear them on my Chord Dave and Chord Mojo, well these do play them with all the energy, and tunefulness (without sounding Harsh) of the Vinyl. Have a lot of respect for JA and the team at stereophile, but would be nice to get Dave reviewed by Fremer and see if it passes his "analog ears" test. (I'm pretty confident he will be pleased)

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