: Srajan Ebaen
Financial interests: click here
Sources: 2TB iMac 27" quad-core w. 16GB RAM running OWS 10.8.2, PureMusic 2.02, Audirvana 1.5.10, Metrum Hex, AURALiC Vega, Aqua Hifi La Voce S2, 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, Nagra HD DAC with MPS [on review]
Preamplifier: Nagra Jazz, Esoteric C-03, Bent Audio Tap-X
Power & integrated amplifiers: FirstWatt S1, F6; Crayon Audio CFA-1.2; Goldmund Job 225; Gato Audio DIA-250; Aura Note Premier; Wyred4Sound mINT; AURALiC Merak [on loan]
Loudspeakers: Albedo Audio Aptica; soundkaos Wave 40; Boenicke Audio W5se; Zu Audio Submission; German Physiks HRS-120, Gallo Strada II w. TR-3D subwoofer
Cables: Complete loom of Zu Event; KingRex uArt, Zu 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, GigaWatt PF-2 on amps
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Rajasthani hardwood rack for amps
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 (no VAT): €4'890

After I'd reset our car's GPS from American to British English for a far sexier lady announcer voice, I was told to take the next slip road right. It took me a bit to catch on. My leggy gal in the box meant on-ramp. The same is true for the digital highway. Some DACs get you there via multi-bit R2R slip roads. The majority take the main one-bit on-ramp. With DSD's resurgence, the most logical thing in today's rein of Delta-Sigma silicon would be conversion of PCM to DSD. And DACs from EMM Labs, Meitner, Nagra, Playback Design, PS Audio and Sony do exactly that. Numerous player software can also and on the fly. For those beholden to PCM and R2R conversion, the choices are dwindling supplies of new-old-stock chips; coding an FPGA like Chord in the UK do; or doing a fully discrete execution of the necessary resistor arrays as MSB and TotalDAC champion it. As I already detailed in Aqua Hifi's first review, our able team from Italy stick to NOS. Of the remaining options they consider Burr-Brown's legendary 24-bit PCM1704 available in U, J and K grades the ultimate conversion IC. Thus they prefer it to Texas Instrument's current ΔΣ PCM1795 replacement and the vintage Philips TDA1541A and Analog Devices AD1865 R2R chips. Needless to say, Aqua's flagship valve-hybrid La Scala MkII gets the 1704 in top K selection. With paralleled chips for fully balanced dual mono—4 x 1704K—that's good for 24/384 over the I²S input on RJ45 called AQlink. All other inputs of AES/EBU, coax, BNC, USB and optional AT&T glass fiber are good for 24-bit 192kHz.
Analogue out over a fully discrete rigorously opamp-free output stage is on both 2.6Vrms/100Ω RCA and very stout 5.2Vrms/200Ω XLR. For best results those shouldn't be used simultaneously. XMOS-based USB 2.0 is fully upgradeable and of the asynchronous transceiver type. Due to modular build, all of the PCB modules are upgradeable should Aqua's engineers discover ways to improve things over time. Warranty is a generous 5 years. That shows confidence in their products particularly for as fast-moving a sector as digital. Acoustic Quality's commitment to purity says bafongul to upsampling. They refer to it as direct from decoder or DFD. It bypasses BB's on-chip digital filter. The stiff middle finger at op-amps continues with transformer-based passive I/V conversion. And chippy regulators. Their regs are executed fully discrete with Mosfets, Jfets and BJTs. That's for both the analog and digital power supplies. For single-stage voltage gain, the La Scala goes class A and hybrid by direct-coupling LED-biased ECC81/12AT7 triodes to high-voltage current-buffer Mosfets. Without coupling capacitors or feedback, there's wide bandwidth, low output impedance and "no overshoot or ringing". High-speed opto-couplers create galvanic and magnetic isolation between the digital stage and analog ground. The power supply gets two EI trafos for digital and analog respectively. The regulated soft-start anode supply is a "virtual battery" Mosfet design. Finish is grey Nextel for the casing with a clear-anodized fascia whose controls switch power, inputs and phase.
La Voce II left, La Scala MkII right

Cristian Anelli and Stefano Jelo of Aqua Hifi above [photo from Annuario Audio]

La Voce MkII with Pro-Ject iPod dock, Bakoon AMP-12R and planar 'phones from Oppo, HifiMan and Audeze at left.

If you reference my equipment listing, you'll spot Metrum's Hex and AURALiC's Vega as two of my long-term digital companions. For headfi I also have the Eximus DP-1; and on my night stand Aqua's La Voce II. That's the all-transistor brother of today's flagship. I find the La Voce to be a near-perfect stand-in for the Hex. Aussie contributor John Darko had contributed to our three-part review of it and independently written up the Vega. He was thus intimately acquainted with my own references. What's more, he described their sonics exactly as I did. When he later called Aqua's La Scala MkII the very best DAC he'd yet hosted (for his review of it click here) I was curious.

The Hex is my go-to DAC for the big rig preceded by SOtM's top battery-powered super-clock'd USB bridge via AES/EBU. If the La Scala was the next step up the mythical mountain, I wanted to survey my music from its higher vantage point. Luckily Aqua were game. How would twice the coin and some glowing bits improve over the La Voce S2? Before we go there, a brief detour into current digital trending.

Buzz-word compliance is its de rigueur mortis and mega pixel count. It preys on misinformed consumers who shop by the numbers. Hence by mid 2014, AMR's iFi division had gone positively purple with glee to announce 768kHz PCM and DSD octa compliance. By then DSD256 whose very first commercial files had just begun to appear was already passé. DSD512 was the new 'in' to remind us that all life is cyclical. It spirals out of control. Then it collapses and begins anew. On cyclical, in the crusades Christianity had its holy wars. Today it's the turn of Islam. In hifi the former were the THD and IMD wars. The latter's present equivalents target digital sample rates. Faced by such accelerating madness, Aqua pray for all-out peace. Their assalaamu a'laikum or pax vobiscum is refusal to participate. Opt out. Say no to DSD and anything above 24/192. How refreshing. If John Darko's assessment had it right, this decision was far from counter-productive. Quite possibly it was the crucial enabler. Obviously neither Metrum's Hex nor Aqua's La Voce had upsampled, quadrupled or DSD'd. Yet on those I was sold already from close familiarity. Time out then from the digital hamster mill which would turn us into octagenarians well before our time. Mind, I'm not singling out iFi. They were simply first to hit those particular numbers. More will undoubtedly follow. That's the whole mechanism of fashion. It's a lemming brigade.

But it's not as though fashion were bad per se. Sometimes it's simply good to return to basics and reset one's odometer. 00000. Today that means an old-style approach to D/A conversion, albeit implemented in the 21st century with modern parts and sonic references. One might exclude the glass bottles from the 'modern' appellation but then remembers that their type remains available in current production.
Screen capture medley from iFi's website