[iamalex]

Artix7 hacking requires quite a hign price but it is not unbreakable. For example, Hydra-z and amanero has been fully copied including code inside chips. What a shameful market in China. Anyway, we still have quite nice original developers like holoaudio's Jeff, Singxer' Leter who make good products for us.

So is it a "steal" of your design, even if it may be legal - or how do you feel about it?

 

[ToroFiestaSol]

TL;DR version:

- Airst makes a deal with Massdrop to build a R2R DAC.
- Airist doesn't know how to build a R2R DAC.
- Airist hires chinese copycat design team.
- Chinese copycat design team sells Airist a 1:1 identical copy of @sosolar work.
- Airist doesn't even know wth they did.

Conclusion: buy a DAC from @sosolar if he ever builds one, don't support scammers and uncultured copycats.

 

[ToroFiestaSol]

So is it a "steal" of your design, even if it may be legal - or how do you feel about it?

Is that even a question? Of course he feels bad, is his work!
Sheesh, such lack of empathy should be illegal.

 

[musicheaven]

What do you look for in a DAC? Everyone has their own answer to that question. For some, name brand recognition is key - based either on respect for designer's reputation, or brand heritage, or simply pride of ownership. Others look for the latest and greatest DAC chip or proprietary FPGA scheme in lieu of off-the-shelf solutions. Some may want a tube-based output stage, and some look for non-oversampling designs (those last two groups often overlap). The remaining obvious aspects: feature set, aesthetics, and price, help narrow down the choices to a manageable handful.

One choice that was all but replaced by newer technology, but is now enjoying something of a renaissance, is the R-2R DAC. This type of design can be done "on-chip" - the PCM63, the PCM1704, the AD1862, etc, all out of production at this point. Or, it can be built around a discrete resistor ladder network, which is definitely the trend right now. You'll find discrete R-2R designs at the heart of expensive models from MSB, TotalDAC, and Aqua HiFi, just to name a few, all with stratospheric price tags. But you can also find some excellent options from Metrum and Denafrips that aren't exactly low-budget, but remain within reach of many real-world users.

One thing you rarely see is a discrete R-2R design in the sub-$500 category. The handful of R-2R DACs that do exist in that space tend use an on-chip design - not necessarily a bad thing, but it does give less freedom for the designer to truly make the device their own. The one exception I can think of is from Audio GD and it sounds pretty awful in my experience... so I try to forget it even exists (and I actually like Audio GD, in general). Seeing this hole in the market, Massdrop paired up with Airist Audio to bring us their own exclusive take on the discrete R-2R DAC, for a mere $349.



I'm not going to waste time going into all the specifics, as the Massdrop x Airist Audio R-2R page does an excellent job giving us the scoop. But I do want to point out a few interesting aspects that stand out. Then, it's on to listening impressions.



First up, Massdrop describes the heart of their design like so: "this sign-magnitude DAC has two independent 24-bit ladders with 48 resistors apiece per each of the two channels, which cancel out errors and distortion for purer processing." I'm told the resistors have a 0.05% tolerance which is better than Audio GD (0.1%) but not as good as Denafrips (which start at 0.01% get better as you move up the line). You'll find plenty of companies out there who don't mention that spec at all, so I'm pleased with what I see here.

Tolerance isn't everything though. As Audio GD somewhat successfully argues, there are other clever ways to approach this issue. To that end, the Massdrop Airist R-2R (hereafter referred to as the RDAC) sports a CPLD with custom programming specific to this product. This works its magic to further improve the network accuracy. For those unfamiliar with the term, a CPLD is like a less complex FPGA, which is not designed to be upgradable in the field. While I love the fact that expensive DACs from PS Audio and Resonessence Labs can be upgraded year after year due to their FPGA cores, I can forgive a $349 product if it doesn't offer any improvements a couple years into ownership. Some of the more potent modern CPLD chips are nearly as powerful as their lower-tier FPGA counterparts, though don't expect Chord-level processing power here. Still, this all shows far more ambition than your standard off-the-shelf DAC chip sporting a slight variation of the reference design.



The output stage is built around 5 opamps per channel. Each side gets a combination of three AD847s, one LT1128, and an OPA2134.

Massdrop uses the modern XMOS XU208 USB controller and offers galvanic isolation across all three inputs (USB, Toslink, coaxial). The device can handle up to DSD128 via USB, or DSD64 (using DoP) on the SPDIF inputs. Clocking is done by low phase-noise units from NDK. Once inside the device, DSD signals are converted to PCM, as the ladder DAC can't actually process DSD. I'll discuss the ramifications of this soon enough.



Worth noting: the USB connection is a microUSB rather than the standard full-size connection we normally see on desktop DACs. This has to do with size (the RDAC is not very tall) but also longevity... microUSB supposedly has a greater operation lifetime than its full-size counterparts, and USB C is not ubiquitous enough to be a good fit here. I thought this was weird and sort of annoying when I first encountered it. Now I'm used to it and don't think it's a big deal.

The power supply is a 5V/3A wall-wart, augmented by voltage stabilization and regulation once the juice makes it inside the chassis. This, along with the somewhat minimal connectivity, is the most obvious sign of cost cutting. Old-school R-2R DACs that I've owned in the past almost universally sported massively overbuilt power supplies, so I was worried this would deter my enjoyment of the little RDAC. Again, I'll discuss this aspect momentarily.

Notice I didn't mention build quality as being a sign of cost cutting. This device does not look like a budget product. The enclosure is low-key but well done, with the same interesting ventilation hole design up top as we find in the various Massdrop exclusive headphone amps. The LED indicators are deliberately soft (I hate bright LEDs that light up my room) which shows the care put into the design. Overall the device reminds me very much of the NuForce Home Reference series from a few years back - the most well done member of that family being their DAC100 which I believe was a roughly $1100 product. Not bad company to be in considering the price here. My only real complaint is that it doesn't quite have a satisfying heft to it - likely due to the power supply situation.



Another quick note: I'm using a review loaner which isn't finalized in a few minor details. Specifically, the back panel will have some changes, such as relabeling the RCA jacks to say "output" rather than "input". Also you'll note the enclosure color doesn't perfectly mirror the "matching" Massdrop amp stacked on top. Apparently they changed the formula to make it less prone to fingerprint smudges this time around, but are still working on getting a better match. Don't be alarmed by that, and don't expect the final product to look identical to what you see in my pics... but it's close enough to give you the general idea.



Now, onto the listening. My system consisted of the excellent Euphony PTS music server, powered by a Keces P8 linear PSU, and running Roon to stream music from a NAS in the other room (plus the occasional Tidal release). A simple CablePro Revelation power strip helped wrangle a maze of Cabledyne AC cables, while interconnects and digital cables from BetterCables made all the critical connections. Amplification came from the Massdrop Cavalli CTH, though I later swapped that out for a Rupert Neve RNHP, and eventually a Pass Labs HPA-1 for more critical listening. I also swapped in various USB decrapifiers in a quest to determine how well-sorted that input might be. Lastly, I added a Wyred4Sound PS-1 linear power supply to see what improvements could be had over the stock wall-wart. Headphones used were all over the place - Sennheiser HD650 and modded HD800, Fostex TH-X00, modded AKG K812, 64 Audio A18t, Audeze LCD-2 (pre-Fazor), Focal Elex, and Ultimate Ears UERM. That's a good mix of low and high impedance cans, with varying signatures and sensitivities.

I wasn't quite sure what to expect. After all, my limited experience with Airist was not particularly impressive. I heard their one and only product, the Heron 5 headphone amp, when it first came out. For the $1999 price tag it carried at the time, I was not enthusiastic. It sounded decent, and external fit and finish were rather nice, but nothing stood out as being worth anywhere near what they were asking. I later heard the price was chopped in half which is a big step forward, though I still don't think I'd find the amp compelling in a sea of worthy competition.

Connecting the Massdrop RDAC to my Euphony server via USB, it showed up in the system as a device called "Sandpiper". A quick Google search revealed that at one point Airist had what appeared to be a working prototype that they were willing to display at shows. I'm told that Massdrop worked with them on a number of design aspects centered around both improving the design and keeping the cost low. I don't know if Airist will ever come out with a version branded under their own name, but if so I'm told it will be something altogether different than the Massdrop RDAC. Note that production versions will display the correct "RDAC" info over USB rather than "Sandpiper".

I first burned the RDAC in for about four days straight, mainly because I was busy with other stuff. To get a baseline sound, I started off with some old favorites in standard lossless 16-bit/44.1kHz resolution, played over USB from my Euphony server. Amplification was the Massdrop CTH (with the stock tube, which is hard to beat), and headphones were the trusty HD650.



The resulting sound didn't really jump out at me - which I figure is a good thing at that stage. Whenever feel like I'm immediately floored by a massive holographic presentation, or insane detail, etc, that's usually a sign that something is blown out of proportion and will seem annoying after a short while. No, the RDAC was generally neutral, had very nice extension on both ends, and was overall unobjectionable in the best possible way.

Upon further listening, I began forming the impression that the RDAC is, above all else, a very "natural" sounding DAC. From Meshuggah to Mendelsshon, timbre is convincing and lifelike, with impressive tonal weight that isn't overly accentuated. Soundstage is suitably spacious but, perhaps more importantly, surprisingly tangible. It's very rare that an affordable DAC manages to recreate that almost holographic, "reach out and touch the performers" feeling. Again, I've heard more height, depth, and certainly more width from other devices, but the RDAC captures a certain magic that goes beyond soundstage size. That said, with certain headphone and amp combinations, I could see the argument for finding it a bit restrictive - particularly if one is accustomed to the more artificially stretched presentation that seems popular in some circles. Not trying to disparage anyone but for me, accuracy and believability are more critical than sheer soundstage size alone. If you want more size without losing that natural feel... you'll have to move up to a significantly more expensive class of DAC.

Switching gears, I swapped out the lovely sounding HD650 for the less forgiving HD800. In modified form it is less brutal than stock, but still very demanding on source quality. The RDAC did not let me down. Detail retrieval, like soundstage, is in one sense "adequate" but in another extraordinary considering the price. This thing is not a detail monster in the traditional way, where a tipped-up treble region creates artificial resolution. But neither is it dull sounding, or overly dark as some of the older R-2R designs could be. The RDAC comes off as prioritizing a natural sound versus stretching for more open, airy, and extended. It's not what I'd call dark, but it might take a bit of getting used to for some people. Then again, for some, it will immediately feel more "right" than most affordable DACs on the market.

Treble is remarkably free from grain. Vocals sound particularly compelling, whether male or female. The raspy croon of Adam Turla (of Murder By Death) is placed on equal footing with the simplistic clarity of Chet Baker (yes, he sang from time to time, check it out when you get a chance) or the stunning Jacintha. All are presented with what I'd call an accurate, even-handed treatment, free from gimmicks or coloration. I normally expect this level of sonic truthfulness to come at a much higher cost. Would I like just a bit more air and extension? Perhaps, and if that's the goal there are ways to bring more of that out (which I'll discuss momentarily). But at $349 the performance is absolutely compelling. Again, we are talking about quality over quantity here, and I think the RDAC nails it in that regard.



Switching to the $499 Rupert Neve RNHP headphone amp unlocked new levels of performance. As good as the CTH is, there seems to be more potential in the RDAC waiting to be set free. I noticed a more solid footing in terms of low end extension, which added a greater sense of rhythmic bounce to the presentation. I also found the lower midrange to be more fleshed out, while remaining very tightly controlled. The biggest improvement of all was the ability to more comfortably use my UERM and 64 Audio A18t, which don't play all that well with the CTH. The A18t in particular sounds amazing in this setup - bottomless lows, meaty mids, and delicate, flowing treble that seems perfectly balanced. This is absolutely a winning combo.

The RNHP also confirmed what the CTH already hinted at - the RDAC has impressive dynamics and a black background, which makes bombastic classical (Stravinsky! Holst! Respighi!) a joy to play. It holds itself together beautifully when the music gets complex. Seriously, at this price, I can't think of anything that can touch the RDAC in these aspects. It's the type of thing which scales very well as the user upgrades ancillaries and headphones to tap its full potential.

Lastly, swapping in the big Pass Labs HPA-1 brought another improvement, albeit a rather small one this time. Certainly not worth the extra expenditure over the little RNHP. That means the RDAC realistically tops out somewhere between the $499 Neve and the $3500 Pass - I didn't have time to continue searching for the best cost-to-performance dance partner, but I bet it's closer to the Neve (unless we add some upgrades to the RDAC....)



When it comes to inputs, the USB lags slightly behind the coaxial. I didn't spend much time with the Toslink so I won't comment on it. Using coaxial out from my old but great Simaudio Moon Orbiter, I got even more convincing treble and slightly more accurate imaging. Standard USB is no slouch though - a lot of affordable DACs compromise in this area, by necessity, but the RDAC is perfectly presentable. Using a BMC PureUSB or a Wyred4Sound Recovery brings the USB back into parity with coax, or perhaps even gives it a slight lead - either way, the difference is small enough to be insignificant. I don't currently have a more affordable USB gizmo to mess with, but it's very possible something from Schiit or iFi would do the trick on the cheap.

The plot thickened when I noticed that USB accepts sample rates up to 384kHz, while SPDIF tops out at 192kHz. I switched back to the Euphony server and set Roon to upsample everything to 384kHz. This brought out the best I had yet heard, even without a USB widget in play. Character didn't fundamentally change, but everything snapped into focus just a bit more - treble was more refined, imaging more precise, and the overall presentation even more weighty. Some DACs don't seem to care what you feed them but in this case, a diet of really-high-resolution PCM is just the ticket.

DSD on the RDAC is interesting. Everything gets converted to PCM internally, but it still sounds quite good. I continue to believe the mastering on DSD releases is responsible for most of that format's benefit, and of course that's not something you lose even with an intermediate PCM conversion stage. I played around with having Roon bring everything up to DSD128, but that seemed to give a bit of edginess/crispiness to the treble - the first time I experienced that on the RDAC. It also did something weird to the midrange which I can't quite put my finger on... simultaneously too relaxed and too forward. I gave up analyzing it and went back to 384kHz upsampling and all became right with the world. Note: Native DSD64/DSD128 material sounds fine when played on its own. I just think the process of upsampling PCM to DSD in Roon, which then gets converted back to PCM internally, is not the best route to take. I'm undecided on whether downsampling native DSD to PCM in Roon rather than letting the RDAC do it internally makes any difference or not. Hopefully that all makes sense.

Another upgrade I found was swapping the wall-wart for a Wyred4Sound PS-1 linear power supply. The PS-1 is a modular design, and you'll need to run the high current amp card to satisfy the 3A requirement of the RDAC. This really seals the deal in terms of treble refinement, dynamics, and the always desirable inky-black background. At this stage we are dealing with a $349 DAC supported by a $900 power supply - that's a bit silly, but it's the only thing I have right now with the proper 5V/3A specs. I suspect one could get most of the way there by spending less on another option, which would make more sense in this context.



All I can tell you is this - the RDAC, powered by the Wyred PS-1, with a Wyred Recovery in the USB mix for good measure (also powered by the versatile PS-1), being fed 384kHz PCM via Roon upconversion, rivals many DACs I've heard south of ~$2,000. If one could achieve similar results by a more frugal PSU and USB decrapifier selection, then all the better.

Is this ridiculous? Why not just start with a "better" DAC right from the start? Let's talk about compromises. Massdrop and Airist have developed an excellent platform. But their price target means they can only go so far. While they do give us power supply and USB solutions that work surprisingly well, they are likely held back by the $349 asking price. Those users who want to bring things up a notch (or several) are then free to spend more on upgrades in those areas, while everyone else still gets superb baseline performance. It makes total sense to me. I would happily recommend this solution over many "higher end" DACs which cost around the same price as the cumulative RDAC/PSU/USB widget, so they've done something right in the development of the core product.



To wrap thing up: Massdrop's Airist R-2R DAC offers massive performance at a relatively low price. It's not ideal for those who demand sonic fireworks, with artificially large soundstage and boosted treble. If that's your idea of great sound, the RDAC will come off as boring and cramped. I happen to think the RDAC's presentation is the more "correct" version. It focuses on the fundamentals and makes beautiful, natural sound, much the same way my favorite vintage R-2R DACs did. But while many of those had an admittedly pleasing warmth, the RDAC is more neutral and even handed (though arguably still just a bit warmer than truly neutral). For offering a musically satisfying performance, with amazingly pure treble and accurate imaging, the Massdrop Airist R-2R DAC is a clear winner. Factor in the ability to upgrade it to an almost shockingly high level of performance, and you can see why it earns a very strong recommendation.

Hi I noted you have a Keces linear power supply, too bad this is the P8. I think if one would not mind shedding another 350$, you could buy the P-3 with dual outputs which one of them can be ordered with the 5V-3A output, having an extra 12V-3A output for some other connections. I think this would most likely yield the best synergy between the too and live up the R-2R.

 

[iamalex]

Is that even a question? Of course he feels bad, is his work!
Sheesh, such lack of empathy should be illegal.

You're absolutely right. It's just a too strange story with the told 2 years of development from Airist (which seems to be at least only half the truth), the long time it took massdrop and Airist to give an answer (which wasn't really satisfying) and sosolar in the middle of all not knowing what's really going on (business-wise). Of course I'm with sosolar if it's a steal, and would hope he gets the credits (and the money?) he deserves.

 

[Raphael DeLaGhetto]

This community loves drama

 

[Raphael DeLaGhetto]

December 18th is the shipping date. That's a huge oof, didn't expect that long of a wait. I may just wait until next year for a second drop.

 

[Lawrenceho]

When designing a new product, one of the fundamentals is to study available, similar products in the market and benchmark them. And R2R has an extremely small market. I found it very difficult to believe they hadn’t heard about sosolar’s work over years of R&D, until 2 days ago.

It is so surprising and disappointing to see how many users in this thread not giving a damn on the I.P issue.
I was also looking forward to this drop because of the aesthetics and pricing. A suspension to this drop until everything clarified is the most reasonable thing can be done at this point.

 

[Th3Drizzl3]

well its live now. wonder if there will be issues along the line though with this one. hmmmm

 

[soekris]

Delivery Dec 18, 2018 ?? Massdrop / Airist are welcome to contact me, I'll be happy to design and deliver a plug compatible module with same sound and functionality but better specifications, at a lower manufacturing cost (the pictured board use some unnecessary expensive parts) in good time for Dec 18, 2018 shipping, and not hampered by rights as I own my designs ....

 

[sosolar]

TL;DR version:

- Airst makes a deal with Massdrop to build a R2R DAC.
- Airist doesn't know how to build a R2R DAC.
- Airist hires chinese copycat design team.
- Chinese copycat design team sells Airist a 1:1 identical copy of @sosolar work.
- Airist doesn't even know wth they did.

Conclusion: buy a DAC from @sosolar if he ever builds one, don't support scammers and uncultured copycats.

Interestingly, it is actualy 25bit implementation. They say it is 24bit(as I promoted in my taobao page). It seems that they dont know what happens on the last bit of decoding circuits.

 

[sosolar]

Delivery Dec 18, 2018 ?? Massdrop / Airist are welcome to contact me, I'll be happy to design and deliver a plug compatible module with same sound and functionality but better specifications, at a lower manufacturing cost (the pictured board use some unnecessary expensive parts) in good time for Dec 18, 2018 shipping, and not hampered by rights as I own my designs ....

I bought your 1021 module few years ago. That was fascinating especially the spec. I admit that I cant reach it, you so smart.

 

[musicheaven]

Interestingly, it is actualy 25bit implementation. They say it is 24bit(as I promoted in my taobao page). It seems that they dont know what happens on the last bit of decoding circuits.

Delivery Dec 18, 2018 ?? Massdrop / Airist are welcome to contact me, I'll be happy to design and deliver a plug compatible module with same sound and functionality but better specifications, at a lower manufacturing cost (the pictured board use some unnecessary expensive parts) in good time for Dec 18, 2018 shipping, and not hampered by rights as I own my designs ....

Seems that you two guys should have joined forces with your know-how to create a competitive R-2R DAC ahead of Massdrop/Airist.

 

[soekris]

I bought your 1021 module few years ago. That was fascinating especially the spec. I admit that I cant reach it, you so smart.

Thanks for the nice words. But you also did a nice module. Competition is good, stealing is very bad, you should sue them because it's a clear copyright violation.

 

[sosolar]

Thanks for the nice words. But you also did a nice module. Competition is good, stealing is very bad, you should sue them because it's a clear copyright violation.

We have a short talk with our lawyer about this today, measure will be taken very soon. Anyway, market and customer will tell the truth. Thank you for your kind remind.