March 2011

World Premiere!
Opera Consonance D-Linear 7 High Definition Digital Music Interface
And D-Linear 8 192kHz/24-bit Decoder
Very impressive and fun to use too!
Review By Tom Lyle

  Opera Consonance's D-Linear 7 and D-Linear 8 are two types of digital components that I have never had the pleasure of auditioning in my system. They are also two types of digital components that I never even knew existed. I suppose if I was asked whether a Chinese audio firm manufactured anything like these two components I would surely have answered in the affirmative, for these days it seems as if anything is possible. Although, if asked whether anyone would want such a component, my answer to such a question would surely be less definitive. But after only a short time I started thinking: "I may have not ever desired them, but now that they're here, thank you very much".

OK, I'm not the most advanced of computer-audiophiles on the planet, but I'm far from clueless. I have a few terabytes of FLAC files on outboard hard-drives, and I've been listening to these files through USB digital-to-analog converters for quite some time now. Of course there are other computer audiophiles that are way ahead of me and been performing tasks such as pumping music wirelessly throughout their entire homes for even a longer period of time. But my excuses have always have been, at least as far as I was concerned, quite rational (but read on before you write me off too quickly). And I strongly suggest reading this entire review to discover all that these units have to offer other than the simple act of decoding digital signals.

My main system has the host computer in the same room (I prefer "listening room" rather than "man cave". Whatever). This system is the larger of the two that includes the rather large Sound Lab DynaStat electrostatic/hybrid speakers aided by a Velodyne subwoofer. FLAC files are played on Foobar 2000 or MediaMonkey running on a 3.20 GHz Dell PC with 8G RAM running Windows 7. The visiting Opera gear's AC was routed through Virtual Dynamics power cords which were connected to a PS Audio Power Plant AC regenerator, which in turn connected to one of the two listening room's dedicated power lines. The second system is an all tube based system with Dynaudio stand-mounted speakers. While they took up residence in this system both the D-Linear 7 and 8's AC cords were connected to a Panamax power conditioner. Before the Opera gear arrived, the only "high-quality" audio source in this system located two floors away from the server has been disc-based digital and the occasional use of an iPod or a classic AR FM tuner.

D-Linear 7
Opera calls its D-Linear 7 both a "digital music interface" and an "advanced network player". Simply put, it is both a self-contained Internet radio and a DAC. To get digital information to its internal Digital-to-Analog Converter one can connect a hard drive via a network using a NAS (Network Attached Storage) drive, or directly using a dedicated drive's (DAS, Direct Attached Storage) USB cable. Also, one can connect a USB flash drive, which some call a thumb drive, among other euphemisms, to an input jack on the front or rear of the chassis. Either of these connections can contain just about any lossless music file including WAV, WMA, APE, FLAC, ALAC, ACC. In the future other formats will probably be able to be decoded because of the D-Linear 7's Linux operating system's ability to accept downloadable firmware updates via its USB inputs. The D-Linear 7's DAC can process files with word lengths up to 24 bits with sample rates up to 192 kHz. Opera claims that it uses specialized a 32-bit "high-performance" embedded multimedia processor CPU, and boasts an "industrial class" digital phase-locked loop (DPLL) clock system that reduces jitter to "ultra-low" levels. Best of all is the inclusion of its built-in Internet radio with the ability to receive over 10,000 stations with both easily navigable regional and genre menus. The D-Linear 7's Internet radio can connect via LAN (using an Ethernet cable) or Wi-Fi with the a dongle that Opera calls a custom "wireless network adapter" that is provided with the unit. The D-Linear 7 has a relatively large LCD touch-screen to navigate all the set-up menus, and displays the current track information being played either from the attached or network hard-drive, or the Internet radio station.

On the rear panel of the D-Linear 7 are two USB inputs, one labeled "USB Device", which is for a physical connection of a hard drive, the other, "USB Host" is for a portable flash drive. To the right of those inputs is the Ethernet connection labeled "LAN". There are two digital outputs, a AES/EBU which is an XLR-type connection, and an RCA coax. The stereo analog outputs are gold-plated unbalanced RCA jacks. The power switch, fuse, and IEC AC output jack for its removable power cord are nearest to the top of the cabinet on the right side. The clean and almost spare modern-looking front panel of the D-Linear 7 has only the LCD touch-screen, and for convenience an input labeled "USB Host" for a flash drive connection. The four-inch high, nine-inch wide, and twelve-and-a-half-inch deep cabinet is lifted almost 0.75-inch off the shelf by its four composite cone-shaped feet.

Where to start? Although I ended up spending quite some time listening to files from a hard drive attached to the USB Device input and from a shared hard-drive through the network, I was most interested at first in using the D-Linear 7 as a stand-alone Internet radio. It worked just as well using a hard wired Ethernet connection when in the main system as when receiving a WiFi signal in the second system two floors away from the wireless router. But more on that in a bit. Of course more useful in assessing its sound quality was when I used a hard drive connected to the D-Linear 7 to decode FLAC files. When playing files the screen had the same layout as when playing the Internet radio – track name, number, elapsed time, sample rate, volume, and the expected CD player-type functions were listed. Using the D-Linear 7 to play files was intuitively simple. All of its functions are duplicated on its remote.

If I were the owner of this unit and was dependent on it to play my music music files I would spend some time massaging the data on my drives. The majority (but certainly not all) of my files were ripped from CDs by using Exact Audio Copy (EAC), and each artist, then each album of each artist was a separate folder. The D-Linear 7's shuffle function ("random play") only randomized files within the same folder. Other than that snag, using the D-Linear 7 was super-simple to use. Setting the D-Linear 7 to receive a WiFi signal worked flawlessly even when a part of the second system two floors away from the wireless router. Like I said, I used a cable between the hard-drive and the D-Linear 7 instead of a NAS drive, only because I don't own NAS drives, per se. But this was not such a big deal because I was also able to access the drives that were hard-wired to the host computer by setting the network functions on the computer to "share" the hard drives through the network using the resident Linksys-G broadband router.

D-Linear 7 Sound
So how did the D-Linear 7 sound? I have to say, its sound quality was quite good, at least when playing files from my hard-drives. With the claims in the Opera's literature regarding the specifications of the D-Linear 7's internal DAC I can't say that I was surprised that I reached this conclusion. Having lived through the early days of digital, plus the fact that I'm as dedicated to analog playback as ever, it is about time that standard 44.1/16 files have a sound that even detractors will begrudgingly agree at least approaches "audiophile" quality. The DACs that are produced today by any company worth its salt are refreshingly fine sounding, and this was true of the D-Linear 7, no doubt about it. There was appreciable air surrounding instruments, and from the upper midrange on up there wasn't even the slightest hint of digital glare unless I was playing certain files that were poorly mastered in the first place (as an aside: I have spent a good deal of time in recording studios in the late 80s to around the mid-90s that specialized in rock and pop that routed their final mixes of analog multi-track masters to a two-track Panasonic DAT. A shame). The D-Linear 7 possessed an open window into the sound of the files I was playing, and dare I say it was transparent to the source. Yup, I said it: transparent. I could not detect any "sound" that was imposed by the player itself, letting me hear what the original intentions of the artist and engineer on every file I played. The D-Linear 7 possess five digital filter settings, none of which I thought improved upon its already fine sound. To my ears it sounded as if too much of the highest treble was attenuated with any filter setting other than default. If that's what you like in digitally reproduced sound, go for it. For me I'd rather hear the original signal, warts and all.

It wasn't until when I later performed some quick A/B comparisons between the Opera and my resident Benchmark DAC1PRE that revealed the Benchmark had an edge in sound quality. The Opera had a lighter sound, that is, the Benchmark had more low end weight and a slightly more detailed sound (without sounding etched) that benefited just about any file I played through it. But the Opera D-Linear 7's internal DAC produced a sound that is certainly competitive to just about any DAC I've heard within its price range, and although putting it up against the Benchmark is informative, that comparison really isn't fair – one is comparing apples to oranges, not only because the Opera has a self-contained Internet radio.

The Internet radio function was much more fun and way more convenient to use than listening to Internet radio on the host computer's browser, favorites settings, and any plug-in I've ever used. But the sound quality of Internet radio is highly dependent on the radio station selected, that is, a bit rate of 128 Kbps is the highest I got from any station that seemed worthy of my time. Therefore, "serious listening", that is, listening to Internet radio while planted in the sweet spot paying full time and attention was not something I did very often. But that's just fine, as even terrestrial radio stations are more for off-axis enjoyment and as anyone who enjoys the format will tell you – and with over 10,000 Internet radio stations available by only pressing a few buttons on the D-Linear 7's remote and scrolling through its menus, the world was my musical oyster. This was true especially in the less revealing second system, where the sonic flaws of the DAC (which, as I said, were only slight) when listening to full-rez files through its DAC, and especially the Internet radio (which were more than slight). No, the second system isn't a kitchen iPod dock table radio, its a system with PrimaLuna monobloc tube amps, Balanced Audio Technology preamp, and stand-mounted two-way Dynaudio speakers, but still, it certainly wasn't as Olympian as the main system. And its less revealing nature made listening to Internet radio that much more enjoyable. The Opera Consonance D-Linear 7 is a piece of audio equipment that is fun. That alone makes it worth recommending.

D-Linear 8
At first I thought that the Opera Consonance D-Linear 8 was another USB DAC – which makes sense, because at the time of this writing it seems like this type of DAC is not only in vogue, but what the audiophile community wants. And for good reason. But the D-Linear 8 is different. After unpacking the D-Linear 8, placing it on an open shelf of the Arcici Suspense equipment rack, I then started searching for the USB input. I should have read the literature first. On the back panel of the sleek looking Linear 8 are both balanced XLR and unbalanced RCA analog outputs; and RCA coax, optical, and AES/EBU (XLR) digital outputs. And, lo and behold, screws to connect the 2.4G antenna that receives a signal from the provided USB transmitter, which attaches to any unused USB input on the host computer. This transmitter needs no software to be installed in the computer, and will work with any modern PC or Mac. The front panel of the D-Linear 8 has a selector that to choose the input of either the wireless USB input, its AES input, optical input, or coax input. On the front panel there is also a neat, retro looking meter that indicated whether or not the D-Linear 8 is receiving a wireless signal, and a headphone input with a volume control for this headphone input.

Opera describes the Opera D-Linear 8 as a component that only is a USB wireless DAC receiver, but a "universal" DAC for transports, in that it can decode signals from its Opera's own Consonance HD interface, as well as DVD player, Blu-ray disc player, and cable TV decoders and satellite receivers. It contains an onboard "high-end" (their term) headphone amplifier, and the D-Linear 8 has both RCA and balanced XLR outputs.

I was most interested in using this device to receive a wireless signal from my host computer. I left enough time one afternoon to adjust to a learning curve that I should expect from a unknown technology, but that was unnecessary: I plugged in the USB dongle to the computer which automatically disconnects the sound card options of the computer, and after selecting the wireless USB input on its selector knob, music played through the D-Linear 8. Done.

D-Linear 8 Sound
As I mostly use my physical CD collection for referencing the booklets these days, it should surprise no one that my first few listening sessions were with the Opera receiving the wireless USB signal. But I did connect a transport to the D-Linear 8 via its coax RCA input using a Virtual Dynamics 75 Ohm digital cable and spun CDs. Hooked up this way, its sound quality was better than the wireless method. But still, the joy of listening to the D-Linear 8 decode Foobar 2000 or MediaMonkey while shuffling the relatively huge amount of data stored on my hard drives was enough to overlook this fact. This was especially enjoyable when the D-Linear 8 located two floors away from the host computer. I could get used to this. Lest I give readers the wrong impression – the sound quality of the wireless transmitter was not bad by any means. As with the D-Linear 7, the more forgiving tube-based system with stand-mounted Dynaudio speakers in the common living space on the first floor or our home was where I also tended to listen to the D-Linear 8 for enjoyment, not just reviewing purposes. Another aside: I made the mistake when speaking to the distributor of the Opera gear of calling the USB wireless system used by the D-Linear 8 as "Bluetooth". It is not a Bluetooth wireless system, and whether Bluetooth wireless' poor reputation in regards to sound quality is deserved or not (it is), the technology behind the wireless audio, at least as used by Opera, seems to preserve the most important qualities that make high-end sound high-end sound. Of course there are degrees to which separate the good from the very best, and this is of course true when describing the difference between the USB wireless signal of the D-Linear 8 and its direct digital input. Is the trade-off worth it? I cannot make this decision for you, all I can say is that the D-Linear 8 not only worked as advertised, and although not perfect, performed at a level that I think most audiophiles will be able to live with for the huge convenience (and fun) factor involved.

One of the reasons I was convinced that the sound quality of this unit was up to par is when I was listening to the D-Linear 8 while Foobar 2000 was on shuffle. On came the first movement of Shostakovitch's Symphony No. 15, the chamber music version played byviolinist Kremerata Musica on Deutsche Grammophon. It's out-of-print, which is quite a shame because it is not only one of the best sounding 44.1/16 recordings in my collection, it is also is quite a fine performance and unique arrangement of this great piece of music. The movement opens with his version of a toy shop, first with the sound of a high note of a glockenspiel, followed by the whimsical yet sardonic sounds of flute and violin straight out of Shostakovitch’s famed vocabulary, as well as quotes not only from Rossini (William Tell Overture) but from past works of his own as well. Bass drum and tympani whacks had enough muscle behind them to shake the room (and showed that the rather diminutive Dynaudios could pull this off), and all the sounds were well sorted out in a soundstage that never sounded cluttered, largely because of the realistically scaled sonic distance between the instruments. This was true regardless of the sarcastic cacophony that Shostakovitch attempted to impose. As far as chamber music goes, this piece is as demanding as one can imagine, and if you have even an inkling of the range of my taste (or lack thereof) in music, likely the D-Linear 8 would be asked to decode everything from classic '70s hard rock, to modern jazz, to chamber and orchestral, to world music, to '50s soundtracks, to electronic music – and I'm sure I'm leaving some genres out – all while I was wearing my reviewers hat. I would surely notice if it faltered. The only hiccup I heard was an actual hiccup, when the signal dropped out a couple of times. Changing the "band" on the Opera's USB dongle on the PC cured that, as it has eight available channels to optimize its signal transmission. There was no need to change any settings on the D-Linear 8.

When I listened to the few hi-rez files on my computer's hard-drive the sound quality for the most part took a giant leap forward. One was an album that I recently downloaded from HDtracks, John Coltrane's classic A Love Supreme. I implore anyone who has even the slightest interest in jazz to download this album, as anyone with ears will acknowledge that the 96kHz/24-bit sound on these files blows away any other digital rendering of this masterpiece. Elvin Jones' cymbals in particular have a realistically natural sizzle that is startling, and Coltrane's in-the-room-with-you presence is wonderful. That higher resolution files through the D-Linear 8 sounded better than "regular" files is to be expected, and the fact that it can decode files up to any resolution that one is likely to encounter is impressive. But I have to be honest – although I did indeed listen to plenty of files with a resolution of higher than standard CD I did a heck of a lot (or greater) more listening to these plain vanilla 44.1kHz/16-bit music files, if only because of the sheer number of those recordings in my collection. But still, it is nice to know that the ability to decode these files is there when the need presents itself. As far as other disc player formats are concerned, I did take the time to use the D-Linear 8 to decode the few two-channel music DVDs I own, and my finding were consistent with the other formats played through it, at least comparatively so. And this is a good thing, as I was impressed not only by these higher resolution files. On the files sourced from Red Book CDs, its sound through its digital input was very similar to the D-Linear 7. But both unit's sound quality was dependent on the type (and thus quality) of source file as well as the method of input, and variable enough that publishing "ratings" at the end of this review would be pointless. Comparisons of the D-Linear 8 to the Benchmark DAC1PRE resulted in similar findings – but only when comparing discs played via coax input, where it was nearly as good, but not quite, in a variety of departments. But it was again helpful to remind myself that this comparison wasn't really that fair because they are two products that have in common only the fact that they can decode a digital signal. The comparison of the Opera's wireless signal vs. its direct digital input were more instructive, yet rather pointless. It is what it is. But read on.

Game Changer
OK, and now for the game changing game changer – hooking up the D-Linear 7 and 8 in tandem using the provided AES/EBU connector transformed these two converters into a single unit that had a sound quality that surpassed either of them when used separately. This also made it possible for the D-Linear 8 to have a "direct" connection to files in the hard-drive, and this not only proved to be convenient, but made a vast improvement in the sound quality of the signal that came forth out of the D-Linear 8's analog outputs. Among many other benefits, not only could the Internet radio be fed to the superior DAC of the D-Linear 8, but feeding high-resolution files such as the aforementioned Coltrane album took took the sound quality to a level that reviled the best digital I've heard for quite a while coming out of my speakers. Not only could this combo hold its head high next to the Benchmark DAC1PRE the D-Linear's could decode a files with up to 192kHz/24-bit as opposed to the Benchmark's 96kHz/24-bit. This last fact may be significant to more than just a few audiophiles. As the downloading of files with a resolution of 96kHz/24-bit is increasing, so are what we know as the highest available legal downloads these days, namely 192kHz/24-bit files.

While the Opera gear was on loan I listened to hi-rez files downloaded from quite a few sources, with a rate of as high as 192kHz , but some others including a few from Reference Recordings that had a slightly lower (but perhaps insignificant? Let's save that discussion for another time) sampling rate of 176.4 kHz. These tracks sounded similarly outstanding. I was driven to play the "Reveries" album numerous times, this album has Eiji Oue conducting the Minnesota Orchestra in pieces as diverse as Ravel, Faurè, Tchaikovsky, and Sibelius, and I ended my day listening to a personal favorite, the track of Eric Satie's Gymnopedie No. 1 quite a few times before calling it a night. Everything any audiophile could ask for in terms of not only resolution but involvement were present during the playing of these spectacular orchestral tracks. I spent even more time, I'd say most of the weekend, listening to hi-rez tracks – but later discovered that even standard 44.1kHz/16-bit tracks sounded much, much better with the combination of the D-Linear 7 and 8 than just relying on the 7 to decode files sourced from files on the hard-drive. The bass response in particular was markedly improved, it seemed to reach deeper and also seemed to have a sharper focus. Tracks such as the third movement of Ralph Vaughan Williams Sinfonia antartica with its organ pedals that shook the window frames of the listening room. This great recording on Naxos with Kees Bakels conducting the Bournemouth SO is legendary for its bass response, and the D-Linear 7/8 combo did not disappoint. Also noteworthy was my time playing back some stuff from the great-electronica-scare-of-the-1990s, including the slamming sixth track of of Front 242's album 05:22:09:12 Off, which I don't feel at all comfortable mentioning it by name in this publication.

The combination of the two Opera units will cost one just a bit over two grand, and I most audiophiles would still consider this an affordable option for a DAC. Yet the combination offers a plethora of features not available in an "ordinary" DAC. And if just the sound quality of the decoding prowess of the combo is the only feature that one considers, it is still just about unbeatable at this price.

Since it does take up some real estate on the front panel, I would be remiss in not at least making a mention of its headphone input of the D-Linear 8. I was pleasantly surprised. I used both the easy to drive Grado SR-80 'phones and the larger, and of course more expensive, Sennheiser HD-600 cans. The D-Linear 8 had no problem getting more than acceptable sound out of either. The smooth volume control on the right side of the front panel had a nice high-end type feel, and there was no problem in reaching a sufficiently low volume even when using the super-efficient Grados, and conversely both pairs of headphones got loud enough up to the level where hearing damage became a concern before I hear any distortion. Comparing it to a Headroom dedicated headphone amplifier was revealing in that it demonstrated that the D-Linear 8's internal headphone amp fell a little short in terms of bass extension and overall instrument separation, but I guess that's to be expected. Still, the D-Linear 8's internal headphone amplifier sounded much more like a well thought-out circuit than an afterthought.

Final Thoughts
The literature that is available for the D-Linear 8 is minimal, and along with its stablemate the D-Linear 7 I often wished for a more comprehensive manual. The D-Linear 7's manual was especially lacking in details that perhaps if were present would have prevented me from getting lost in the deep set-up menus, where I became baffled a few times and had to give up and contact the distributor for help. Not just this, but I was at a loss when it came to discovering the features that these units had to offer, again, this was especially true regarding the D-Linear 7. I even had the distributor contact me just as I was finishing up this review with more things he had discovered! But I guess neither manual was so bad for units that are making their first appearances on these shores, and I assume that this will be corrected in short order (in fact the distributor let me know shortly before I submitted this review that they were being revised).

One more thing: if they had showed me the plans for the D-Linear 7 or 8 before its design was concluded, I would have mentioned its lack of an input for a computer's USB cable which was, at least in my main system, sorely missed – especially once I had the two set up together. OK, the wireless transmission of the digital signal is the D-Linear 8's raison d'etre, yet the inclusion of an asynchronous USB input on either of these units would enable one to have the option of hard wiring the computer to this DAC, and would have made using an outboard hard-drive hooked up to the D-Linear 7 an option rather than a necessity. Although in my conversations with Opera's North American distributor Grant Fidelity, they seemed to think that Opera was very open to suggestion, and gathered that it would not be unreasonable that this feature would be included in future revisions of the units. Although I'm not an audio engineer, I couldn't imagine that it could raise the price of either of these units that much. Though even without this, the D-Linear 7 and 8, and especially the combination of the two, not only performed impressively well but were awfully fun to use. And especially fun to listen to.

A Note From The Manufacturer
Through firmware upgrades, the D-Linear7 will support new functions. Consonance plans to let customers use any smartphone or PC through the WIFI network to control the D-Linear7, iPhone/iPad/iPod Touch and Google Android systems would be supported. The customer would setup his/her remote control software on their smartphone or tablet PC, then they could manage their music files, which are stored in the PC's shared folder, NAS or removable storage device, connected to D-Linear7.

Opera Audio

Specifications
TD-Linear 7
Analog Output: 2.5 RMS (RCA)
Analog Outputs: Gold plated unbalanced RCA
Distortion: Less than 0.002%
SNR: More than 120 dB
Digital Output: 0.5Vpp (RCA @ 75 Ohms), 3Vpp (AES @ 110 Ohm)
Digital Outputs: Gold plated RCA and gold plated XLR balanced
Digital inputs: Three USB Host, 1 LAN, 1 SCHC Card
Dimensions: 4.33 x 8.86 x 12.60 (HxWxD in inches)
Weight: 3.31 lbs.
Price: $1125

D-Linear 8
Signal Output: 2.5V RMS (RCA, XLR)
Digital Inputs: Coaxial S/PDIF,  TosLink optical, AES/EBU and wireless USB 
Analog Outputs: Unbalanced RCA,  balanced XLR and 6.5mm headphone jack
Frequency Response: 0 Hz to 50 kHz
SNR: More than 118dB (RCA, XLR)
Distortion: Less than 0.001% ( RCA,XLR)
Dimensions: 3.94 x 8.86 x 12.60 (HxWxD in inches)
Weight: 7.7 lbs. 
Price: $945

Company Information
Opera Audio
798,No.2 Jiuxianqiao Road
Chaoyang District
Beijing, China

Voice: +86-10-59789461
Fax:+86-10-59789265
E-mail: operaamp@vip.163.com
Website: www.opera-consonance.com

Distributor Information:
Grant Fidelity
6239 Center Street SE, Suite 100A
Calgary T2H 0C6
Alberta Canada

Voice:(403) 984-3882
E-mail: grantfidelity@gmail.com
Website: www.grantfidelity.com

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