Reviewers: Srajan Ebaen
Financial interests: click here
Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 12.2), PureMusic 2.04, Qobuz Hifi, Tidal Hifi, COS Engineering D1, Metrum Hex, AURALiC Vega, Aqua Hifi La Scala MkII, SOtM dX-USB HD w. super-clock upgrade & mBPS-d2s, Apple iPod Classic 160GB (AIFF), Astell& Kern AK100 modified by Red Wine Audio, Cambridge Audio iD100, Pro-Ject Dock Box S Digital, Pure i20, Fore Audio DAISy 1 [on review], Metrum Acoustics Pavane [on review]
Preamplifier: Nagra Jazz, Esoteric C-03, COS Engineering D-1
Power & integrated amplifiers: Pass Labs XA-30.8, FirstWatt SIT1 & F6; Crayon Audio CFA-1.2; Goldmund Job 225; Gato Audio DIA-250; Aura Note Premier; Wyred4Sound mINT; AURALiC Merak [on loan], Goldmund Telos 360 [on review]
Loudspeakers: Albedo Audio Aptica; EnigmAcoustics Mythology M1; soundkaos Wave 40; Boenicke Audio W5se; Zu Audio Submission; German Physiks HRS-120, Gallo Strada II w. TR-3D subwoofer, Crystal Cable Minissimo [on review], soundkaos SK16 [on review]
Cables: Complete loom of Zu Event; KingRex uArt, Zu Event and LightHarmonic LightSpeed double-header USB cables; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Arkana Research XLR/RCA and speaker cables [on loan]
Power delivery: Vibex Granada/Alhambra on all components, 5m long cords to amp/s and subwoofer
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc stereo/Krion and mono/glass amp stands [on loan]
Sundry accessories: Acoustic System resonators
Room: Irregularly shaped 9.5 x 10m open floor plan with additional 2nd-floor loft; wood-paneled sloping ceiling; parquet flooring; lots of non-parallel surfaces (pictorial tour here)
Review component retail in Europe: €6'000

Not the DAC-pre! But the size and concomitant weight of these amplifiers explains why they weren't shipped on short-term loan instead.

Discreet. People having affairs tend to be; including music lovers who start their obsession with hifi. But sooner than later, our sort misspell it. That rarely gets sorted. Now we do discrete instead. Our newbie receiver breaks up into tuner and integrated. Next the integrated becomes a preamp and amp, followed by the preamp's power supply splitting off. Then the power amp breaks up into two mono amps before their power supplies hop out. The monitor speakers get a separate mono subwoofer soon to be stereo'd. Super tweeters follow. Then crossovers externalize. That's followed by bi- or triwiring, later bi- or tri-amping in full dual mono. What was a discreet system has become a maximally separated affair. Each function has been assigned its very own ecosystem in a dedicated enclosure. Due to mushrooming box count and associated costs, such systems are neither discreet on looks nor expenditure. They've become the elephant in the room.

The same applies to circuits. The epitome of the discreet amplifier is the gainclone. Its output device is literally an amp on a chip. That chip is smaller than—remember those?—a quaint postage stamp. Such devices are known as operational amplifiers; op-amps for short. The vast majority of digital gear wouldn't even work without the large-scale integration of complex circuitry onto chips. Those can be off the shelf like AKM, BurrBrown/TI, Crystal, ESS, Metrum, Phillips; or bespoke as custom-coded field-programmable gate arrays. But discretniks have begged exception from this rule for years. The first commercial D/A converters to reject on-chip conversion probably were from MSB. Later a Japanese DIYer published his take on a fully discrete DAC. That was followed by French brand TotalDAC who started as DIY but then commercialized something very similar. As the word 'ladder' in multi-bit ladder DACs indicates, they operate with a large array of miniaturized switched resistors inside their chips. Voilà, an opportunity to build discrete such DACs with external arrays and full-size resistors. That's conceptually related to how relay-switched resistor attenuators are built. Of course one still needs so-called glue logic which controls these resistor banks and their high-speed relays or switches to behave as needed. And the resistors need to be very stringently matched to represent the precise values necessary. Even this wildly oversimplified explanation explains why discrete DACs are so rare.

Where today's assignment goes, the rarity compounds. That's because this product is from Russia. On the global hifi map, this country which held on to industrial vacuum tube use far longer than the West remains a huge blank spot. True, Russian expat to the US Viktor Khomenko made a name for Balanced Audio Technology. They introduced us to the triple-nipple 6C33C and the 6H30 which BAT marketed as the line-level 'super tube'. Landsman Vladimir Shushurin settled in NYC and built up Lamm Industries as a very high-priced purveyor of valve gear. Arkana Research audio cables with their exclusively rare-earth conductors are a group of American audiophiles under the helm of a Russian scientist. There might be more Russian designers in the field. Yet none of them run Soviet brands. One in fact suspects that their international success ties most directly to operating from anywhere but Sovietistan. There are successful hifi companies right outside Russia. Think Estelon from Estonia, AudioSolutions and Less Loss from Lithuania and so forth. But Russia itself?

This isn't the place to sort out why. Suffice it to say that the editor of Russia's AudioMagazine Artjom Avatinjan considers S.A. Lab (Sound Analysis Laboratory) to be their most important domestic brand. It's precisely why we syndicated two prior reviews of their valve gear with him. Today that baton passed. Designer Alexey Syomin wanted me to conduct a review of his phono stage, perhaps to undermine perceptions of patriotic bias or otherwise just for a change. When I informed him that I'm homo digitalus without the vinyl chromosome, he instead suggested his new fully discrete DAC. Without knowing anything about it—price, data compatibility, socketry, tubes*, transistors or both—I accepted. That's because our entire rationale for syndicating reviews from countries like Australia, Germany, France and Poland has been enthusiast's desire to fill in blanks left by distribution and exposure. Boots on the ground, syndication implies working with domestic writers and publications who enjoy unique insight into their markets. Largest on this map of terra incognita loom Japan and Russia. The former is well known to host a highly developed audio underground of valves & horns. Yet we in the West rarely learn more than that. With Chris Sommovigo expatriating to Japan, we might soon have our own man inside their embassy. Given the size of its populace, one suspects an equally vibrant DIY underground in Russia. Here we know even less save for the occasional YouTube or FaceBook incident. Now I finally had my very own opportunity to make a minuscule dent in this barrier. 'Nyet' so wasn't in the frame. Да, абсолютно it was instead. Yes, absolutely!
Not the DAC-pre either but definitely its creator.

* Given Alexey's unabashed membership in Russia's pro-valve party, I rather expected tubes. I was aware also that he's authored pure transistor gear, albeit from the perspective of a tube designer who prefers transformer coupling. If his DAC didn't do USB, I'd have the Audiobyte Hydra+ USB bridge from Romania to step in. That it wouldn't do DSD was part of the ladder DAC concept. I could care less. 99.9999% of my music files are PCM. If it were very expensive, I'd not blush. Nor if there were no dealers outside Russia. Some assignments are about dream gear. So I had zero notions on any of these scores, just that it was a discrete DAC from a Russian designer with a proven track record and 10+ years in the business.