OCD. Obsessive compulsive disorder.
DDC. Digital/digital conversion.
Soundaware's flagship digital transport proposes the simple but tantalizing equation of OCD + DDC = ODDC for an obsessive digital-to-digital converter. Need proof? 

Let's start with raw connectivity. 
1 = SD card slot based on FAT32, EXFAT or NTFS formatting whose associated card reader processes up to 2TB cards navigatable via intuitive display.
2 = USB 2.0.
3 = 100mbps RJ45/Ethernet for DLNA, Samba and AirPlay network streaming. 
4 = WiFi antenna with Bluetooth APTX. 
5 = USB 3.0 with custom-coded FPGA. Data acceptance is 32-192kHz PCM or DSD 64/128. 
6 = 24/192 Toslink compatible with DSD via DoP.
7 = 0.5V 24/192 coaxial S/PDIF. 
8 = 5V 24/192 AES/EBU digital. 
9 = native I²S and DSD via HDMI which Soundaware call Saw-Link as an interface also for their MR1 digital audio player. Compatible with Denafrips DACs for example.
10 = 3.3V RJ45/Ethernet as an alternate link for native I²S and DSD.
11 = 3.3V BNC word-clock output.
12 = 3-5V BNC word-clock input at 22.5792MHz.
13 =3V-5V BNC word-clock input at 24.576MHz.
14 = IEC power inlet.

In the plainest possible terms, one can enter and exit the D300Ref any number of digital highways and byways and, whilst at it, sync the internal clock to an external master clock. The SD slot becomes a self-contained server, no PC or network access required. PC users will see this component as a fancy reclocker/USB bridge which can output native I²S and DSD into DACs with the requisite ports and silicon.

Under the 43x8.8x20cm WxHxD hood covering a 7kg case in silver or black without any visible screws (those come through from the bottom in each corner), we get a not knee-capped but super-capped virtual battery supply à la Vinnie Rossi Lio, Nagra HD Preamp and Classic PSU or Gryphon Audio Design Kalliope. We get precision clocks and custom FPGA code. Particularly for use with SD cards or USB sticks, we get a Soundaware-branded remote from Chunchop and a built-in display whence to navigate folders and files with playlist assembly, repeat one/all, shuffle and the usual modes.

For those without external DAC, Soundaware have the matching A300 player with very similar digital socketry including the SD card slot. That then adds a converter with variable 2.6/5.2Vrms RCA/XLR outputs. Optionally, it can even be fitted with a balanced headphone amp and matching 4-pin XLR socket.

Used as just a digital transport, the A300 obviously isn't quite as OCD as the D300Ref which was conceptualized as an ultimate statement for its sort. Those who are perfectly content to stream digital files off an ancient laptop's USB socket will obviously fail to see any rhyme, reason or rationale for today's deck. To them it's an unnecessary extra box with fancy socketry they wouldn't know what to do with. Fair enough. Hifi comes in all sizes and levels of specialization. The D300Ref is squarely for those who've already pegged it for what it is/does and where it goes the extra miles.

Master Clockers & Bros. To exploit the Ref's word-clock feature requires an external master clock from the likes of Antelope, Esoteric, Jay's Audio or SOtM. Not having one on hand, I couldn't test it. One underwhelming prior experience—with an Esoteric in conjunction with one of their one-box players—suggested that, perhaps, home hifi without the need to sync up multiple digital kit via often long cables like studios do might not sufficiently benefit from external clocks. With our Aqua Hifi Formula's RJ45-carried I²S input not being compadre with the Ref's and no Denafrips DAC on hand to instead test the HDMI-ported version, that interesting and potentially superior digital interface was beyond my scope to sample as well. This left me with two applications I could and would test: using this machine as a USB bridge for the iMac; then as SD card/USB stick memory reader.

I'd compare iMac/Pure Music --> USB --> D300Ref --> AES/EBU --> Formula; iMac/Pure Music --> USB --> Formula; SD card --> AES/EBU -->Formula. If you wonder why AES/EBU and not coaxial S/PDIF, the former is a 5V format, the latter 0.5V. AES/EBU is the by far more robust signal with the better connectors. In two scenarios, Soundaware's circuitry would process the data before handing them over to the DAC. In the third, the iMac's USB data went straight to DAC. It didn't detour through the D300Ref. For the computer feed, this stripped away any benefits Soundaware's reclocking, noise attenuation and jitter suppression might make. Before we proceed, let's state once more how all of this occurred solely in the digital domain. It involved no changes of digital-to-analog conversion. Any sonic differences were caused by just different transports; and adding or subtracting extra circuitry plus cables. The bits=bits brigade should cry bleeding bollocks by now but that's their religious duty, not ours.

The universal serial bus crosses the bridge to serve me a bill. Past the Aqua converter, the remainder of the hardware was Wyred4Sound's STP-SE2 preamp into a pair of WestminsterLab Unum monos driving Æquo Audio Stilla. Being a very resolving unusually linear full-bandwidth system, if aural hairsplitting was on the books—and I suspected that it would be—I'd have the nuclear particle separator for the job. Whether my ears would be sharp enough was an entirely different question. The USB cable was a red KingRex double-header, the AES/EBU an Allnic Audio ZL 3000. 

As it was, my ears were sufficiently pointy still to make out a clear hierarchy. The best performance came from the SD card. Next best was the iMac running through the D300Ref. Last was the iMac straight to DAC. My first test was the title track from the Dulce Pontes album Lagrimas. This Portuguese fado singer has very powerful pipes. Peaks can become challenges. Moving from iMac-direct to iMac-detoured, Soundaware's circuit removed a certain metallic noise from inside her vocals. Pretty soon the most suggestive term for that was rust. Grain or grit too would be applicable but they lack that grungy dirty-yet-sharp connotation. Without taking her foot off the gas as could be cloned with bandwidth-limited valve amps, the singer's throat no longer was lined with those rusty shards like coarse sandpaper. To a lesser extent, I heard the same in the peculiar glassy timbre of the Portuguese guitar. Defaulting to audiophile lingo, crossing the USB bridge sounded purer. Some form of low-level noise or dirty dither was extinguished. When I finally switched the Ref from USB to SD card mode, what happened was finer and still harder to describe. Sounds felt freer, more radiant and flowering; a bit how ink blots blossom on wet paper but in 3D. This removal of an embedded restraint or rigidity was certainly subtle but nonetheless real and repeatable. WIthout image enlargement—no melon-sized throats or extension-ladder fret boards—sounds off the SD card seemed more alive and a such, energetically not physically bigger. Contrast ratio too went up a click.

Already this early into the Referee game, my prior misses—of identifying an 'audiophile server' replacement for the iMac that made a sufficiently obvious sonic advance to feel worth the cost—had finally flipped into a personally exciting find. Just routing the iMac's signal through the Soundaware was an unmistakable improvement; one which I didn't have to imagine yet which I could enjoy without the brain-numbing ultrasonic pollution of WiFi. This meant keeping what I already had and loved but making it work better. I could continue to enjoy Apple's terrific display and functionality plus get that sonic upgrade which €10'000+ servers with their puny or utterly absentee screens hadn't provided. If I wanted to push even further for special sessions, I simply had to drag'n'drop a quick playlist to SD card. Further potential improvements might still come from native I²S mode and, just maybe, from a more effective external master clock than I'd tried before. In short, this Chinese loaner had found a new home. Time for more tunes.

Meddling with the mettle. Was there more to SD transporter duties than work as 'rust' remover with a freer-breathing gestalt? The next track was by Aytac Doğan from a compilation album. It sports the Taksim Trio's qanun maestro playing an Arabian form of what classical Indian music calls alap. Here it is done against tasteful ambiance and standing synth chords. Now I noted a still greater delta between USB/SD modes. It's why it's always sensible to start out with structurally simplistic music. It focuses down on what surrounds and informs plainness rather than getting overwhelmed by sensory overload of very dense complex arrangements. Once one knows exactly where and how a component's difference plays out, one recognizes it more easily on more difficult fare.

Meddling with the mettle. Was there more to SD transporter duties than work as 'rust' remover with a freer-breathing gestalt? The next track was by Aytac Doğan from a compilation album. It sports the Taksim Trio's qanun maestro playing an Arabian form of what classical Indian music calls alap. Here it is done against tasteful ambiance and standing synth chords. Now I noted a still greater delta between USB/SD modes. It's why it's always sensible to start out with structurally simplistic music. It focuses down on what surrounds and informs plainness rather than getting overwhelmed by sensory overload of very dense complex arrangements. Once one knows exactly where and how a component's difference plays out, one recognizes it more easily on more difficult fare.

This lower noise increased soundstage depth for more spatial realism. That's about the often quite subliminal contextual data whereby musical sounds reveal their location ambiance. Another aspect of perhaps the same observation involved inkier blacks. They made for higher contrast and image pop against the backdrop's velvet. Also, the window on tone modulation had opened up just a bit more. I heard more of the deliberate changes Aytac makes to the timbre of his lap harp which at times mimics a more twangy Chinese guzheng.

Still in a minimalist Turkish mood, I next cued up a spine-tingling taqsim by spiked fiddle virtuoso Cafer Nazlibaş. Played with a lot of feather-touch flageolet that just edges the line to flicker between different overtones plus certain quarter-tone steps, it's not well-tempered Western European music so all the more mysterious and 'other' for it. Yet because these strings are played so smack on the very edge, they can easily veer into the strident and nervy. Again, migrating from iMac direct to iMac detoured to SD card transformed that very element. It stripped away the hashy glinty noise flitting about the sounds like metal dust. By evaporating that buzzing cloud which hovered around the bowed strings as Cafer scales higher and higher, I got closer to their stringed essence and unfettered purity without the dreck. As before, eliminating the iMac altogether made the sounds spill out from their virtual containers. For lack of a better word, call it gush factor. It's like the difference between trickling and spraying water. It tastes the same, it measures the same yet energetically, there's a qualitative difference of delivery. Musically, things felt bigger, freer and more exuberant or lush even if in terms of basic soundstage coordinates, everything stayed put and nothing really changed except for depth.

At this juncture I grew curious whether these sterling results could be replicated by getting... well, blue in the teeth. Pairing my smartphone went without a hitch or secret codes. Seconds later, I had wireless tunes via Android's default GooglePlay. My head simply felt toxic from such powerful Bluetooth radiation. It couldn't help but influence my aural mood to think the sound greyish, canned and neon-like artificial. But the feature did work flawlessly. Even if it weren't one's primary playback mode, it really would be a superb socializer for those visitors whose mutant brains are impervious to such strong 2.4GHz bombardment. Like Lethal Weapon's Murtaugh, I'm simply too old for this APTX shtick. Back then to USB and SD card.

PureMusic vs. Audirvana and other twisted matters. Progressing to more complex music, I dropped a short playlist to SD card. This consisted of "Round the Corner" by Jazz harpist Deborah Henson-Conant on the GRP label; "Fly Shadow Fly" by Dhafer Youssef; "Caravana de los Zincali" by Flamenco pianist Dorantes; "Massilia" by the Marseilles formation Barrio Chino; "Sueños" by Jazz clarinetist Eddie Daniels of Stereophile's former Santa Fe haunt also on GRP; the "Schindler's List Theme" by French/Serbian violin ace Nemanja Radulović with orchestra on Deutsche Grammophone [right]; and finally another blackwoodist on the Turkish G clarinet, "Senede Bir Gün" from Hüsnü Senlendiriçi's second-to-last album.

The more intricate and layered tunes had my focus more generalized on the lusher juicier freer quality for the SD card readings. Where they remained structurally basic, I honed in on a solo instrument or vocal. This let me mentally slip inside them and feel out the changes mentioned on the previous page. Because these changes didn't operate in the frequency response or tonal balance domains, many common audiophile terms or ways of looking at things didn't apply. It also didn't help that the iTunes players PureMusic and Audirvana still made a difference when streaming USB to the D300Ref. That was unexpected. I doubt I'd have heard that on a less resolving system.

In fact, this entire review assignment was an advanced exercise. To penetrate from the big fish thrashing water to the far smaller oceanic denizens barely leaving a ripple to finally the passively floating plankton which casts no shadow... such microscopic vision requires that basics be in the can already. You need superior S/NR to make the plankton come up to the surface as it were. Even your attention must be fixed and still lest it'll be drawn to bigger more obvious events. Listener fatigue from simply looking too hard for too long takes its own toll. And so forth. Speaker reviews expose idiosyncrasies far coarser and grosser where overlooking or forgetting them is harder. The purely digital domain is made up of far finer stuff. Even when you hear clearly because your system is resolved enough, your listening skill honed and your attention keen, do you care enough to bother at the end of the day? It takes precious little time to get back to the status quo and hear it as perfect since, obviously, there couldn't have been anything fundamentally wrong with it when this component doesn't right fundamental wrongs like a skewed tonal balance, shrill treble, bloated bass, recessed midrange, bad imaging and the lot. There are sonic improvements; sufficiently valuable in fact for this listener to pony up the hay. But it's important to acknowledge that in the hierarchy of audible issues to sort out, the intercession of this digital/digital converter slash SD card reader is far from primary or even secondary.

The D300Ref is for folks with already mature systems whose discretionary upgrade funds no longer have reasonable cause to be applied elsewhere. The speaker/room interface is sorted, the electronics are, power delivery, resonance control and cabling are. If money remains available for further hardware upgrades not music or altogether different hobbies... then it could indeed be Ref Time like that Miller beer ad. For me it was. That's because for our indefatigable music iMac, it was an unexpected go-faster bolt-on. It improved sonics beyond what previous visitors in the server category had managed. Yet unlike them, it requires no WiFi tablet for navigation. And the iMac remains in charge of wired networking for music downloads and the very rare Qobuz, Tidal or Spotify session. Those subscription services tend to instead run as background fill on the desktop where I work; and to discover new music to buy. Just as an old-fashioned CD player wand did, the Soundaware remote features numerical track access. If you wanted to skip from a folder's 2nd track to the 21st to the 8th then the 15th, it's all just a few thumb clicks away; vintage-tech infrared, not 2.4GHz microwave-oven radiation. Ditto for all other menu functions. When used as just a USB bridge—admittedly costly and unusually big for the breed—the D300Ref bridged performance gaps I'd not seen done before. As an SD card server, it reaches even farther. It's a highly specialized machine with a very specific i.e. narrow job description which many may not even consider wants filling. That returns us full circle with the intro which stated that "those who are perfectly content to stream digital files off an ancient laptop's USB socket will obviously fail to see any rhyme, reason or rationale for today's deck. To them it's an unnecessary extra box with fancy socketry they wouldn't know what to do with. Fair enough. Hifi comes in all sizes and levels of specialization. The D300Ref is squarely for those who've already pegged it for what it is/does and where it goes the extra miles."

And it does go them, those extra metres!