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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, PureMusic 1.89g in hybrid memory play with pre-allocated RAM and AIFF files up to 24/192; Audirvana 1.5.10 in Integer mode 1, Metrum Hex, AURALiC Vega, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2
Preamp/Integrated: Nagra Jazz, Esoteric C-03, Bent Audio Tap-X, Crayon CFA-1.2, Bakoon AMP-12R, Gato Audio DIA-250, Clones Audio 25i [on loan]
Amplifier: First Watt SIT1, Goldmund/Job 225, AURALiC Merak [on loan]
Speakers: soundkaos Wave 40 + Zu Submission, Boenicke Audio W5, AudioSolutions Rhapsody 200, German Physiks HRS-120
Cables: Complete loom of Zu Audio Event, KingRex uCraft and Light Harmonic LightSpeed and Zu split USB cables, Van den Hul AES/EBU cable, Tombo Trøn S/PDIF cable, AudioQuest Diamond Toslink
Stands: Artesania Audio Exotyeric for front end, Rajasthani hardwood rack for amps
Powerline conditioning: Vibex Three 11R on front end, Vibex Two 1R + GigaWatt power strip on amps
 Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review component retail in Europe: starting at €2'180, alternate DAC boards starting at €290

Three-letter abbreviations are like secret hand shakes. What to some means global positioning satellite becomes geopathic stress to others. Either decyphers GPS correctly. And both are connected. CIA can mean central intelligence agency. Or a certified internal auditor. The former should use the latter. NOS can mean a national organisation study. But there's also the Neurofeedback Organization Switzerland. How about tube nutters and collectors of vintage vertical power Jfets? To them NOS becomes new-old stock. And homo digitalos reads it as non-oversampling. The latter two meanings can overlap again.
La Diva CD transport and La Scala MKII at the 34th Taipei show with Rogue Audio and Emme speakers
Take the four chip options which Italian Aqua Hifi offer for their La Voce DAC S2. All of them are R2R resistor ladders. Burr Brown's PCM1704/1704-K has long been discontinued. That makes it NOS. Even so it remains a top choice for designers who dislike current Sigma-Delta converters for Redbook playback. The Philips TDA1541A is an even older-but-goodie R2R chip of the early 16-bit era. That's NOS again and here available in R1 and S1 selection grades. Finally there's the Analog Devices AD1865. That's an 18-bit chip also of the R2R persuasion and also out of production.

Whichever you choose—BB is the default—all are used two up (dual mono) and in DFD mode. That's Aquarian for direct from decoder. It means bypassing all on-chip digital filters. No upsampling. NOS again. Squared if you will. Their AQlink implements the I²S protocol on RJ45 to link to their La Diva disc transport via CAT6 cable. I/V conversion is passive. This says 'hell no' to the otherwise ubiquitous op amp at this juncture. Regulation is by Mosfet, JFet and BJT. No integrated chips again. And that's true for both analog and digital circuits. The output stage then casts another evil eye at opamps. None here either. Discrete is the word. So is being modular. Hence the multi-board upgradeable platform. Word. With the 1704/1704-K chips, the standard BNC, USB and I²S ports are good for 24/192. Who cares about 32-bit/384kHz? Should you do, Aqua's defiance will strike you as backward. For those whose high-resolution libraries max out at a native 24/192, it's a non-issue and a gutsy stiff finger at silly popularity contests.
La Voce on top, La Scala mirror-imaged below
That BNC and I²S rather than coax and Toslink are the standard here reiterates the same level-headed attitude. Ditto the 0/180° phase switch on the front. Aqua Hifi focus on engineering, not fashion. But they aren't snobs about it. Input options can add 24/192 AES/EBU, coax, AT&T fiber and 24/96 Toslink. 2.1V RCA outputs are standard. 4.2V balanced are optional. Output impedance is 100/200Ω respectively. Trim is silver or black for the fascia, Nextel gray for the casing. Size is 450x310x100mm WxDxH. Weight is an unassuming 7kg. Finally the similarly spec'd flagship La Scala MkII DAC adds two ECC81 triodes which are cleverly direct-coupled to Mosfets with LED bias to create single-stage hybrid voltage gain. For that deck our toroidal iron goes EI core and the power supply has to get more complex to support those valves and their heaters.

And that's all she said on the subject of Aqua's current catalogue. It's a 3-up affair purely concerned with digital: one top-loading CD transport—yes, those are still made and that they do one here tells us yet more—two DACs with USB but no DSD or DXD. C'est ça. To get back at acronyms, Aqua is short not for the age of hippies and free love but Acoustic Quality. This somehow reminds me of German firm Aqvox. Back to our Italians headquartered in Europe's fashion capitol of Milan. They pride themselves on investment in long-term R&D. For concrete results they cite their DFD mode which they call proprietary*; discrete high-speed opto-coupling for galvanic/magnetic isolation of digital inputs; a proprietary isolated synchronous discrete circuit for digital decoding and clock management; and their discrete regulator technology.
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* In general, moving digital filtering 'off chip' to a custom-coded FPGA which bypasses the DAC's own on-chip filter is getting more common. For just one example the recently reviewed Antelope Audio Platinum did it and claimed improved performance from 64-bit math and a better power supply over a converter chip's more restricted 24/32-bit topology and thermal die constraints.

In very early 2014 a quick Google search on the subject showed it. Aqua converters had been around in a few incarnations already. Refinements and revisions had been ongoing. Yet on the other side—reviews, ads, forum chatter, general buzz—things were rather less active. The website had just three distributors in Holland, Russia and Taiwan. This underlined engineering over sales & marketing muscle. Having been contacted for a review now not sooner; and not for the tubed €4'890 but more affordable €2'180 model all were suggestive. Aqua had been patiently biding their time to perfect their platform before pursuing a global audience in earnest. That at least was my remote read from the armchair. To see how close I was, company contact Stefano Jelo had to chime in.