Aqua Hifi La Scala MkII Optologic DAC

photo credits: Aqua Hifi unless otherwise noted

Device Type: Digital to Analog Converter
Input: USB, S/PDIF (Coax, BNC), AES/EBU, etherCON RJ45 (AQlink)
Output: single-ended RCA, balanced XLR
Dimensions (W x H x D): 450 x 370 x 100 mm
Weight: 9 kg
Availability: Online and Authorized Dealers
Price: $7,000.00

In my day job I interact with people holding PHD's in various tech fields, including audio. Any faith these folks have in my cognitive faculties has a tendency to ebb quickly when they find out I prefer music on vinyl, even if—and, perhaps, especially if—it's mastered digitally at 16/44.1. My response is to regurgitate a spiel on how music exists for the purpose of pleasure, and I simply tend to receive more of that through vinyl, measurements be damned. Depending on the degree of hostility I might also opt to say that signal to noise ratio is not a genre I care for, and try to change the topic.

Those answers aren't quite satisfactory for them nor for me, of course. The process of pressing music to vinyl unquestionably adds and removes things that result in a deeper pleasure for myself and many others, but what? Why? How? While there is no shortage of armchair theorists littering online forums in torrents of proclaimed knowledge of exactly what these parameters are, there's been a peculiar dearth of DACs that implement these constraints to make a fat buck off of us gullible vinyl enthusiasts. So maybe it isn't so easy, after all.

My current DAC, the Weiss DAC202, measures almost flawlessly. This fantastic feat of engineering also, to my ears, plays music more beautifully and compelling than a vast array of its contemporaries, strongly indicating that measurements do matter. Yet my vinyl setup, while admittedly about three times the price of the DAC, often surpasses it when it comes to pleasure, a parameter we have yet to design a chart for. As my wife and I are rapidly running out of room for records in our small New York apartment, with 6000 more in storage back in our native Sweden, it sure would be practical to find a DAC that can serve as the single source of music and not leave me wanting: I simply can't accept that the wasteful and cumbersome logistic detour via vinyl pressing is going to remain necessary in perpetuity.

One way of injecting some analogue magic into a DAC is tubes in the analogue output stage. While that is only one aspects of what comprises a DAC's sound, the use of tubes in the Aqua Hifi La Scala MkII Optologic DAC was key to pique my interest. Mark Sossa, of US distributor Well Pleased AV, gave me the low-down:

Aqua, since its founding in 2010, has been strictly devoted to researching and developing digital to analogue converter technology unlike other manufacturers who in addition to dacs make other products. It has maintained since then that a Non-Oversampling, R2R conversion method (first with the BB1704k which was then replaced with their own proprietary R2R circuit termed Optologic) with proprietary analog based filtering techniques ("Direct from Decoder") achieves the most natural sound. In addition to this they have been proponents of fully discrete circuitry and not incorporating an integrated volume control (Purist approach). […] The dacs are all fully modular and designed to be upgraded in the future.

In this my reviewing debut at Audiostream I will depart slightly from protocol by not listing all the technical specifications, as I think you’ll find that is better conveyed in formats other than an article. Its innard have been thoroughly dissected elsewhere but for housekeeping’s sake a few things should be mentioned: Besides its Telefunken ECC81 tubes, their “optologic” R2R DAC architecture is a bit of an odd bird in a world of off-the-shelf chips. The R2R design principle uses a repeating cascaded structure of resistor values R and 2R (or even just R, if you’re ok with using more of them), and fewer components in total compared to some other designs. Fewer resistors to match means more precision, but R2R constructions require incredibly accurate component matching for the most significant bits, and that demand only rises with word length. On the positive side, a DAC designer employing this approach has much more wiggle room for creativity and fine tuning than with a chip, and in this case the “optologic” part has to do with the resistor ladder D/A conversion being optically rather than electrically connected to FPGA’s that process the signal further. Looking at the high end DAC landscape, Aqua are not alone in thinking R2R is good for audio but their implementation is decidedly unique.

It’s a reasonably well equipped DAC in terms of input and format compatibility: Inputs are I2S, USB, S/PDIF (RCA), S/PDIF (BNC) and AES/EBU, and it does PCM up to 24/384, and DSD128. If you need toslink, from a TV perhaps, you’ll need to get a converter. There’s no remote or volume control, but in most settings—like mine—this won’t matter much. The tubes don’t take long to warm up and it sounds very good immediately, so if you’re chasing differences after 15 minutes you might as well take up fighting windmills.

The USB cable that came with the review unit must have been a bit banged up, because while it let my iMac recognize the DAC and Roon thought it was sending data, no sound came out. So my initial listening used the Weiss DAC202 as a computer interface over FireWire and sent the sound over S/PDIF to La Scala. This detour allowed me to compare S/PDIF (albeit from an exceptionally jitter free source) to USB once I exchanged the faulty USB cable. If there was an audible difference between these two inputs I could not reliably spot it. Nor did loaner sets of Audioquest Cinnamon and Coffee USB cables let me identify any differences, indicating that the USB interface and the DAC's internal reclocking is as well designed as you should expect at this price range. I primarily listened over USB.




When comparing my Swiss Weiss to the Italian Aqua Hifi it's easy to stumble into prejudice and stereotypes around the national characters of these neighboring nations. But no matter how I try to resist falling into this trap, I have to admit I feel there is some truth to it: The perceived additional warmth of La Scala is really there, sometimes—but not always—at the cost of a little bit of precision. Bass is a great example, where Pan Sonic's "Hades" from 2010's Gravitoni (Blast First Petite, PTYT 045) shows more difference between the twin bass pulses through Weiss, both in terms of frequency and texture, while the Aqua Hifi conveys a sense of physical force and sheer depth that the Weiss can't match. (Mika Vainio of Pan Sonic sadly passed away at only 53 years of age as I was writing this review.)

One reason I bought the Weiss is its entrancing ability to paint a great voluminous cloud of sound for me to stick my head into literally and metaphorically. La Scala performs incredibly well in this discipline, perhaps as well as I've heard any DAC do, but with some differences. With the right material there is a further sense of elevation and effortless weightlessness from the Weiss, perhaps due to its more sternly disciplined bass leaving it with less of a sonic anchor. But weightlessness is not always what one craves.

Note decays and reverb both real and synthetic were stunning, and when the former hands-off to the latter in the title track on Mari Boine's Goaskinviellja (Lean, MBCD 62 / Verve World, 521388-2) the x-ray vision into the mixing desk is as clear as I've ever heard it, but here draped in a creamy richness that makes it exceedingly difficult to care about technical details.

On "Detach" from Hans Zimmer's Interstellar soundtrack, the vinyl lacks some of digital's dynamic punch in the crescendo and the massive swarm of instruments blurs somewhat, but the overall texture and emotional charge is powerfully potent. The comparison shows how similar to really controlled high quality vinyl bass the La Scala performed, while frankly outclassing vinyl in some other aspects.

Piano seems to be something this DAC truly excels at, no matter if I threw Nils Frahm, Joep Beving or Ryuichi Sakamoto at it. But the smoothness and lack of typical digital pitfalls with piano was not due to an overall forgiving presentation: Fortissimo right hand playing had all the piercing sharpness one should expect, but little to none of the digital harshness that too often accompanies it. On a related note, the notoriously 80's digital reverb on "The Host of Seraphim" by Dead Can Dance, both original and remastered, sounded no less clinical and shrill through La Scala even though the song itself was rendered as magical as I've ever heard it.

Remarkably, it's on the purely electronic end of the spectrum that La Scala really shines. I knew Senking's The Dance Hall Walk (Raster-Noton, r-n 142) was a bass monster but La Scala turned it into a jaw dropper not only in terms of bass extension and force, but as a musical coherent whole. Autechre's mind bending reverb workout on "oneum", the closing track of their 4 hour monster release of 2016, elseq1-5 (24 bit WAV, Warp Records, WARP512) is a stunning experience even through a modest DAC, but here transformed to something quite literally unbelievable, in the sense that I'm not sure I knew sound could do this.

On Rachel Grimes' "The Herald" from 2015's The Clearing (Temporary Residence Limited, TRR256) the reed texture of Jacob Duncan's saxophone can feel somewhat more prominent and natural through other sources, but La Scala wins a point back on the piano.

Over the course of listening I found more examples of details where I felt my current DAC had an edge, but it took a direct comparison to find it and often concerned specific details rather than musical enjoyment as a whole. Most prominently it was in complex high frequency material that La Scala consistently delivered less texture and nuance, making records such as Alva Noto's Xerrox Vol. 2 (Raster Noton, r-n 103), an album that is all about texture, decidedly more enjoyable through the Swiss machine. In the classic audio review evaluation parameter of "the shimmer of high hats", this more receded and smooth presentation is also evident. But that trait should be considered in the context of the musical whole, and I can think of many systems and musical preferences where this might not be much of an issue.

Once upon a time I was almost phobically averse to colorations in audio gear, thinking that any enjoyment from equipment with imperfect measurements would be short lived and that I'd soon find some huge drawback, like a genre it clashes with or a texture it garbles. There's perhaps still some truth to that, as with complex treble textures in this case, but if you dismiss this DAC based on its use of tubes or some other theoretical fallacy, take a moment to think about why you listen to music in the first place.

The DAC Stack: Weiss DAC202 (reviewer’s reference), Aqua Hifi La Voce, Aqua Hifi La Scala (subject of this review)

While I'm not quite ready to sell my analogue gear, La Scala MkII is a fantastic product whose warm sonic embrace I can't imagine anyone in their right mind describing as "digital". It does have a sound though: It's wonderfully musical, inviting, enveloping, and entrancing.

Ola Björling works at the frontiers of both technology and human perception as Global Director of VR for MediaMonks.

garrettnecessary's picture

It's an unfamiliar but great pleasure to read a thoughtful review where the music used to audition the system is in my regular rotation!

audiodoctornj's picture

This was a great review, and you really captured the flavor of what the La Scala does.

We were one of the first dealers in the US with a La Scala. We read John Darkos wonderful review and requested a sample.

The La Scala presents a bold, beautiful sound which is just enveloping and extremely musical. We have some of the best digital products on display at the time we had Esoteric, Auralic, Naim, EMM Labs, Meitner, and many others.

The only dac that could beat the La Scala was a dac which was twice the price and that dac did certain things better, while the La scala did other things better.

Aqua Hifi is a wonderful company, they are a passionate group of engineers which build amazing products, that are reasonably priced and supremely musical, add to that modular and upgrade-able.

We would welcome anyone in the New York metro area to give us a call to actually hear an Aqua dac.


Dave Lalin, owner, Audio Doctor
877 428 2873

WA2011's picture

Hey, a very insightful review. I was wondering about getting one of those recently. I've got a nice analogue set but was interested in switching to digital in the near future.


2_channel_ears's picture

The La Scala makes a compelling argument for R2R and tubes. I came upon the Well Pleased room at RMAF 2016 and was transfixed by the sound. I thought it was the best I heard at the show. It is gorgeous and elegant in appearance, that Italian flair I suppose.

I heard the La Scala it again at AXPONA last month. Again, some of the best sound but was paired with, I thought, a less capable speaker than in Denver. Strangely, one of the other DACs at the show I liked turned out to also be R2R with tubes. But alas, the $7k price limits affordability, a price that bumped up since ML first mentioned the product.

Glad we finally got the review for a great DAC.

balazsv's picture

I would love to know how this compares to the totaldac in Michaels's system or to a totaldac d1 single. They seem o represent a similar if not the same school of thought at similar price points.