Next Level Aqua Hifi: Formula, La Scala MKII w/ Telefunken


Your own Personal Jesus? In the DAC world for yours truly, it’s Aqua Hifi’s La Scala MKII converter. The Burr-Brown PCM 1704 infused Italian sits proudly at the top of the Darko DAC Index, quite literally in a league of its own. The La Scala MKII is the DAC I reach for when a ‘best’ first (digital) responder is called for.

‘Best’ is a troublesome gift. One must accept its subjectively sighted foundations whilst being simultaneously mindful that no assessor can assess everything. Not food, not music and not D/A converters. The La Scala MKII is flagged as the ‘best D/A converter’ by these ears and this brain in the context of their collectively finite experiences. There might be a better D/A converter out there – it’s just that I’ve not heard it.

Returning our commentary to formal review territory and with proper professional posturing in tow, ‘best’ translates to ‘reference’.


Since being reviewed in March 2014, the Aqua statement piece – whose €4890 sticker presently converts to ~US$5500 – has successfully defended its RRP-segmented championship title against challenges from the Chord Hugo TT (US$4750) and the PS Audio DirectStream (US$6000).

In foregoing the nice-to-haves of headphone staging, a touchscreen, a digital pre-amplifier, a remote control and even DSD compatibility, Aqua DAC designer Cristian Anelli has poured his entire R&D/build budget into sound quality and sound quality alone. No bells, no whistles, just great-sounding D/A conversion.

The La Scala marries rock solid tonal density to enormous soundstaging for a presentation that connotes a strong but graceful handling of everything from the largesse of macro-dynamic shifts to the minutiae of textural finesse. Hanging up the reviewer cap again, it sounds Lovely with capital L.

And you’d think that’d be the end of it. But no. There’s more…


Ahead of introducing Aqua Hifi’s product line, which also features the more affordable but similarly non-oversampling La Voce S2 converter, to the US market by way of the T.H.E Newport Show 2015, Well Pleased AV’s Mark Sossa underscored these Italians’ un-stereotypical immunity to fashion:

“Aqua does not succumb to the whims of the latest market trends but instead carefully develops its products to withstand the test of time, designing and manufacturing audio equipment marked by the indispensable values of signal purity and acoustic fidelity pursued with the utmost dedication,” asserted Sossa via his press release.

When I caught up with Sossa again four months later at RMAF 2015, his enthusiasm for the La Scala MKII had been fuel injected by a change to another strand of Aqua’s adherence to well-established audio tech: tubes. The Aqua pairs 2 x ECC81 (12AT7) with MOSFETs for a negative feedback-free, Class A output stage. A reminder that a D/A converter’s audible performance resides with far more than just its DAC chip.

Moreover, tubes allow end users to tinker, to introduce alternative flavours via a process known as “rolling” – the audio world equivalent of changing a light bulb.


Sossa had done just that. He’d rolled the stock tubes – either JJ or Genalex according to Aqua’s sales manager Stefano Jelo – for a pair of NOS Telefunken.

And boy was Sossa excited about what he’d heard. So much so that he wanted yours truly to hear it for himself. And by Christmas I had the Telefunkens ready to roll.

The schedule intrusion of CES 2016 meant I’d have to wait until February to plug the NOS tubes into their Aqua sockets for the first time and then again wait out CanJam SoCal until I could be be confident that burn-in doubts had fully dissolved. That was late March. Listening proper then took place, on and off, A and B, throughout April.

These NOS (new old stock) tubes applied to this NOS (non-oversampling, filterless) decoder brought small but noticeable upticks in tonal colour saturation, soundstage depth and, most palpable of all, an even greater sense of ease – a defining characteristic (for this commentator) of digital done well.

The best was now even better.


Even with a recent price hike to €84 for a matched pair from Germany’s Tube Amp Doctor, the Telefunken ECC81 easily earn their status as an essential upgrade for any La Scala MKII owner. If you’ve the cash, don’t think twice – it’s alright.

But wait, there’s more…

March also brought limited and literal first word of a new flagship DAC from the radar-dodging Italians. That word was Formula. Retail pricing of €12,500 would more double down on its predecessor’s €4890. An April 9th launch event in Brussels came and went but little additional info spilled outwards to those not in attendance.

Only a single photo of the Formula graced (and still graces) the manufacturer’s website. At time of writing, supporting text and specifications sheet remain conspicuously absent.

Then came news that Aqua would show the Formula at Munich High-End 2016 and sales manager Stefano Jelo would be in attendance to handle any Q&A. The only proviso: no photos of the man himself. Jelo prefers the hardware to make its own introductions and then continue to speak for itself.


On the floor of the M.O.C. in May, Jelo’s Jean Reno-esque facial features and super snappy suit-up seemingly flew in the face of the man’s ‘no photo’ policy.

One might reason Jelo’s project: the tongue-twisting isolation feet maker ARIAMATERIA who also happened to showing in Munich. Whatever the reason, Jelo’s privacy is his own.

The ARIAMATERIA isolation feet are designed to be porous. Italian crushed stone ‘grit’, either brown porphyry or black basalt from the northern Italian region of Trentino-Alto Adige, is bound with resin and packed into cylindrical shapes of varying thickness before being top-and-tailed with 1mm thick neoprene pads to protect the supported equipment from scratches. All but the range starting AM10 feature an “monocomponent polymer” shock absorber.

That’s a proof-of-life diversion on Jelo’s other project. Back to Aqua. Back to the new flagship DAC. Back to basics – where tubes have gone bye-bye and where in-house built resistor ladders supplant the Burr Brown chips of the La Scala. Formula remains filterless with two R2R boards used per channel, one for each half of the waveform – four in total.


The Formula’s resistor ladder ‘branches’ deliver twice the sample-rate support of the outgoing (and long discontinued) PCM1704 chips whose dwindling supply points to one reason why these Milanese have gone with a bespoke multibit solution. The front panel sports eight LEDs indicating incoming PCM sample rates from 44.1kHz to 382kHz. They also make explicit Aqua’s ongoing red carding of DSD.

‘Round back, connectivity: AES/EBU XLR, S/PDIF RCA, S/PDIF BNC, AQlink (I2S) and USB. The protruding socket in the centre is modular for which the end user can specify AT&T ST Fiber, Toslink or a second AQlink(I2S), AES/EBU XLR, S/PDIF RCA or S/PDIF BNC.

Not only is one input modular. Potentially, so too are many of the Formula’s internal boards: the XMOS USB board, the I2S board, the FPGA board, the DAC boards and the analogue output boards (single-ended and balanced).


The following seven minute video was shot on the second morning of the Munich show. In the outdoor area caffeinated black stuff was being poured ahead of lunchtime’s bratwurst n’ beer takeover. Stefano Jelo walks us through the internals of the Formula. Note the twin potted C-core transformers, one each for analogue and digital sections, and the more sophisticated power supply board.

Only at interview’s end do we hear of another of Formula’s key features: Aqua’s OPTOLOGIC.

Just as a Toslink cable isolates its end points from electrical noise by carrying digital signals transferred to and from light, a similar opto-coupling method is used to join the FPGA board to the four R2R branches and then the R2R branches to the analogue output stage.

According to the manufacturer-supplied .pdf and translated from Italian to English using a combination of websites:

“The [dual function] OPTOLOGIC technique not only completely isolates all the digital processing circuitry (including clock ) from the analogue section in order to create a potential for a clean analog ground. The differential management of the conversion using R2R ladder branches allows for perfect symmetry between positive and negative. This gives the listener a heightened sense of tonal contrasts and naturalness.”

The same .pdf surrenders a little more info on the Formula’s output stage:

“The two analogue boards, one for the buffered single-ended output, the other for the balanced output, are made from fast, discrete components (BJT and JFET) and metal film resistors. No capacitor is present in the signal path. The balanced output is realised with transformers.”


At the end, a plot twist: Aqua intend to make their in-house resistor ladder tech available as a modular upgrade to the La Scala. That makes this story doubly interesting: a new product whose incoming tech will be trickled down to its predecessor, obviating the need for a completely new unit for existing La Scala owners.

Stefano Jelo says he intends to dispatch a Formula review unit down under to DAR HQ sometime in the next few weeks. I’ll be investigating what the big money can bring when one’s DAC spend extends beyond US$10K. Specifically, just how much better the Formula than the Telefunkened-up La Scala MKII? Questions that will be answered in due course.

Further information: Aqua Hifi



Written by John H. Darko

John lives in the NOW + HERE = NOWHERE. He derives an income from the ad revenues of DAR. John is also an occasional staff writer for Stereophile, 6moons and TONEAudio.

Twitter: DarkoAudio
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Facebook: DAR


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  1. I’m really looking forward to your review on this after you’ve had it in house for a while. But if you can, please try to get another $10k DAC in for comparison.

    I won’t be surprised if it hits the top of your list, Aqua makes great stuff and if this is their best try then I’m not going to be shocked if it turns out to top your DAC Index. BUT, if it had a sparring partner that also fought in the same price range then that would at least make for some kind of worth while comparison/feedback.

    Looking forward to it, do what you can and I can’t! 🙂

  2. May I suggest one of the two variants of the new ROCKNA WAVEDREAM DAC, obtainable from Audio Heaven in Melbourne. Thank you.

    • Thanks for the suggestion Kostas but I prefer to deal with manufacturers directly. Besides, the investigative train of thought has already been set. Any >US$10K DAC getting the review treatment AFTER the Formula will see comparisons to it.

  3. Cool.. It’s tightly packed inside just like under the hood of a Lancia Delta HF Integrale.. I’m curious to know what line output transformers they use for the balanced outs, if they’re wound in-house or OEM.. One NOS dac competitor uses Lundahl, another uses Jensen.. It’s nice that we still have a few more choices out there for Multibit Dacs.

  4. You know given that this is another R2R design, and R2R is now the old-new thing these days, it just kinda makes me think that the Schiit Yggy is about the best deal on the planet even at its 2.3k asking price.

  5. Interesting that they chose to follow the Total DAC here by using individual resistors instead of chips for R2R as Metrum, Schiit, and MSB do. The PCM1704 was the premier R2R chip of its day, but that day was a long time ago, and it definitely has its limitations, the 768kHz maximum operating frequency being a big one.

  6. I am not persisting; just suggesting! Perhaps then, the new METRUM ADAGIO and the MSB ANALOGUE with the upgraded POWER BASE. And to be impertinently provocative, why not push yourself way beyond comfort zones of sorts and do the FOUR of them together! It will be a challenge, NOT an intimidation, well within your capabilities. Thanks again. Cheers.