Massdrop RDAC Airist Audio R2-R DAC

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by purr1n, Jun 4, 2018.

  1. purr1n

    purr1n Finding his inner redneck

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    Massdrop RDAC

    https://www.massdrop.com/buy/massdrop-x-airist-audio-r-2r-dac

    Going to pull off a Julia Child's cookbook thing here with no photos and only text. Decided against photos because Massdrop is better at photos and I don't have time for it. I'm going to keep this short and sweet.

    At $350, the closest competition will be the Modi Multibit. Overall, I feel this is a step up from the Modi Multibit. The RDAC definitely reminds me of the old school R2R DACs of the 90s. First things first: those who really want deeply placed stage and stage depth with layering might want to reconsider. The RDAC has NOS qualities. The stage is wide, however, the location of the stage is close. As @Hands says, there is a bit of dimensionality around the instruments with NOS with less of a paper cutout effect, despite the close stage with lack of depth. Now I am not totally convinced this is NOS. It almost sounds like it's somewhere in between, but much toward NOS. Personally, I don't give a crap about headstage with headphones; but I do know that many of you do. Those using Audeze, Grado, or Focal, it doesn't really matter since those headphones don't stage worth shit anyway, no matter what you throw at them. The RDAC does have an open sounding quality to it though - it doesn't sound closed or congested.

    Now let's get to the good part: very good clarity, excellent microdynamics (makes the most of it), nuanced - a very involving listen. This is why I really like it. The tonal balance is even, perhaps just slightly tilted down. The Modi Multibit in comparison is bassier and warmer, and with some congestion, and less bass extension. Plankon, ambient cues, trailing decays are just a touch behind Modi Multibit using USB. Transients are crisper and grip is better on the RDAC. However, SPDIF is where the RDAC really shines. The Modi Multibit is known to scale quite a bit with good SPDIF sources. The RDAC scales even more than Modi Multibit. Everything gets better across the board, with resolution equaling, maybe even nudging ahead of Modi Multibit using SPDIF, and microdynamics being knocked out of the park.

    Despite being SE out, a great match with Massdrop x THX AAA BTW. Makes sense if you think about it. The RDAC chassis is the exact same style and height and width as the THX AAA and MCTH.

    BTW, I did get a chance to hear a prototype version of this using a battery for the power supply. It was even better than the stock switcher. So there is plenty of potential. Sure an uber external LPS and USB to SPDIF add to the cost; but what we have is upgradeable to something better than a Metrum Amethyst, at two-thirds the cost when everything is added together.
     
    Last edited: Jun 4, 2018
  2. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I'll skip the usual introductory stuff about the Massdrop x Airist Audio R-2R DAC (referred to as RDAC from here on out). You can read all that stuff on their product page.

    Though, I will drop a quick note that I dig the slimmer height profile. I really like what Massdrop has going on visually with these audio products. Moving on...

    I actually rather like the RDAC. I am pretty skeptical of discrete R-2R DACs based on past listening. Some have just been absolutely horrendous in my mind, whereas even the better ones always seemed to be missing something compared to a good chip-based DAC. The good ones seem to have this sort of noise removal effect that cleans up some of the microscopic goodies in your music.

    Color me surprised with the RDAC. It doesn't sound nasty, it doesn't sound boring, and it doesn't really sound like it's missing so much of that something. Or, if it is, I'm having a really hard time worrying about it given the positive aspects of the DAC and the relatively low price.

    If I had to quickly describe the RDAC's sound, it has a slightly warm, yet balanced, character and quick, but slightly soft, transients. Some might use descriptors like "analog," "musical," or "organic." It actually reminds me of the newer Metrum DACs with the latest modules. Think laid-back, but still engaged in its role. In fact, I'd go so far as to say it's like a lower priced Amethyst, but a little less forward in staging and more straddling that line between oversampling and non-oversampling.

    The RDAC has a nice, full, powerful low end with good extension. The midrange is liquid and free of congestion. The treble is on the softer side of things but has an effortless, clear quality to it, even if some of the overall details seem to not pop as much as they should. Unless you are opposed to this warmer tone and liquid, but very slightly soft timbre, it should just flow with ease in listening.

    It also has a nice sense of swing and micro-dynamics to it. It's nimble and grooves nicely even despite it's warmer, softer leanings. It's never boring, veiled, or smothering.

    The Modi Multibit, in comparison, is more congested and grainy sounding overall. It struggles more with dense, complex material. It's not quite as powerful and extended in the low end. It sounds a bit more compressed when handling quick, staccato-like micro-dynamics. But the Modi Multibit still shares similar macro-dynamic characteristics with the RDAC, maybe just slightly edging it out. Tough call.

    However, the Modi Multibit does excel when it comes to portraying room acoustics, reverb, air, and an overall well-rounded, three-dimensional view of most individual elements in your music. Drums in particular seem more tangible and real on the Modi Multibit, including the way the sound decays in the room.

    The RDAC, on the other hand, reminds me more of non-oversampling in how it excels with vocals, giving them a sense of being attached to a body with a chest cavity rather than simply being a recording through a mic. (Usually NOS makes almost all individual elements sound more 3D to me, albeit sometimes less focused too, but I don't think the RDAC fully captures that here quite as well as the Modi Multibit. Like I said, the RDAC kind of straddles that OS and NOS line, so it's hard to stereotype its performance.)

    While the RDAC may initially seem to have better layering than the Modi Multibit, I think that's because the RDAC is more laid-back sounding. The Modi Multibit is more aggressive and forward. But if you listen closely, the Modi Multibit bests the RDAC when you pull out live recordings or the like. You get a greater sense of 3D layering and room or venue acoustics. Not that the RDAC does poorly here, mind you (it's at least good), but that Schiit house filter does wonders to music in certain areas.

    Still, staging, layering, and some level of tangibility aside, the RDAC sounds very confident and sure of itself without a sense of showing off. The RDAC has that easy-going, natural, and musical swing sort of personality in spades.

    In terms of resolution and detail, I think the RDAC and Modi Multibit are fairly close. Nothing really seems to be missing from the RDAC, though the presentation is certainly different due to the softer nature and lack of Schiit's own digital filter technology. I expect to see differing opinions on which is more resolving based on what one listens for. Even in my comparisons above, you see where they have different strengths and can imagine how a sense of resolution and detail might play out in one's mind.

    And that's what I think it boils down to: presentation. The RDAC to me doesn't seem like it's necessarily competing with the Modi Multibit. They both have their pros and cons. When I circle back to thinking of the RDAC as more akin to the newer, excellent Metrum DACs, its purpose snaps into focus. I love those DACs, and the RDAC taps into that same feeling.

    At the $350 price point, the RDAC offers a lot for the money. Not everyone will love it, and that's fine. I think it offers something for those that lean more towards the non-oversampling sort of realm than it does those more fond of Schiit's latest multibit offerings. Or, even if you're just curious to try a different flavor, the price point presents little risk. Newcomers should rest easy knowing that, presentation differences aside, they're still getting a really great sounding DAC.

    So, yeah, I'm pretty enthusiastic about the RDAC and was caught off guard when asked to check it out last minute. And I was certainly skeptical. But I'm already pretty fond of it. It's well worth checking out so long as you know it may not cater to your particular tastes. For the type of sound it targets, it meets its goal and at a low price. Most DACs aiming for this sort of sound are either too expensive or are underwhelming regardless of price. This is an excellent addition to a relatively thin subset of the market.

    Source note: Only tested both DACs with the Soundaware D100 via SPDIF.
     
    Last edited: Jun 4, 2018
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  3. Torq

    Torq MOT: Headphone.com

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    Massdrop x Airist Audio R-2R DAC

    About a year ago I was approached to provide some early feedback on a new multi-bit (discrete R-2R) DAC. It didn’t have a case. It didn’t have a projected price. It didn’t have a release date. And it didn’t have a name - simply being referred to as “RDAC”.

    First impressions were distinctly positive, even compared to some of the stalwarts in this space, to the point I was quite anxious both to learn what it might be sold for and to hear how the final iteration was going to perform. So, when about a month ago I was offered a unit with the final production electronics, properly cased, and ready to be subjected to a formal review, I jumped at it.

    Today the veil comes off and what is now officially called the “Massdrop x Airist Audio R-2R DAC” (or, “RDAC” for short) is public and being formally offered for sale, at $349.99, starting on June 6th:

    RDAC.jpg

    This post will cover the basics and, of course, the most important factor – how the thing sounds (in both pure and relative terms). I’ll follow it up with a couple of additional posts covering additional technical details and thoughts on pairing with other gear.

    Major Features

    The interesting features of the RDAC are buried inside the unit - the exterior being an unassuming, but stylish matte-black housed in a chassis that stacks perfectly with the Massdrop x series Cavalli amplifiers:

    • Dual 24-bit discrete R-2R ladders, per channel, in sign-magnitude configuration.
    • Bit-level buffering/isolation on the ladder resistors.
    • Separate PCBs for the resistor ladders vs. I/O, conversion and other processing.
    • Internal power regulation and reference voltage stabilization.
    • Low phase-noise NDK clocks.
    • Custom decoding and filter implementations.
    • USB (galvanically isolated) and S/PDIF (COAX and TOSLink) inputs.
    • PCM native conversion up to 24 bit/384 kHz.
    • DSD support to DSD128 (via internal PCM conversion).

    How Does it Sound?

    The TL;DR; here is simply that the RDAC sounds marvelous.

    The signature is one of general neutrality with a touch of sweetness to the mid-range and upper registers, and a distinctly “pristine” quality/clarity to the sound. Overall presentation is open with a good sense of air but is neither lacking, nor carrying too much, tonal weight/density. The RDAC’s rendering is fluid, articulate, nuanced and well balanced - capable of excellent top-end delicacy while simultaneously plumbing a tuneful, driving, bass-line and keeping vocals present and lucid.

    The strongest, and most enduring, comparison I can make for the Massdrop x Airist Audio R-2R DAC is that, at least from a signature perspective, it sounds like a Holo Audio Spring DAC and Soekris dac1541 got it on - and this was the result. It exhibits some of the sweetness that I found so beguiling with the Spring DAC combined with the distinctly “pristine” quality to the sound rendered by the dac1541.

    While the RDAC is not quite on the same level with all technicalities as those two units, it’s surprisingly close and the combination of their better sonic aspects results in a very compelling delivery with a broad variety of music.

    In More Detail?

    Tone is lovely and pure, with just a hint of sweetness. I’d stop short of calling the presentation romantic or euphonic. There’s just enough “sugar” to keep the otherwise “pristine” or “super clear/resolving” delivery on the “musical side” of things vs. drifting off towards being “analytical” and is, for me, a more engaging listen because of it.

    Extended sustain on piano notes, from my own pieces, exhibit none of the strange tremolo or vibrato that I’ve found in some other discrete R-2R DACs that would be considered natural competitors to the RDAC. Here … the tone remains pure until the notes naturally ebb away.

    Timbre is natural and realistic. Instruments are easy to identify reliably, even in very complex orchestral works and when they’re separated by relatively minor familial differences, purely by how they sound (without resorting to locational cues). Individual oices, similarly, are easy to identify and localize, even when faced with multi-part close-harmonies.

    Transient performance is excellent, almost NOS-like in fact, with plucked strings, discordant brass and aggressive percussion all exhibiting surprisingly rapid and impactful attack/bite. Switching to electronic music and the impact and transient speed remains … play the first 60 seconds of “The Rat” (Infected Mushroom, “Army of Mushrooms”) and you’ll see what I mean. Or run something like “Along this Road: Kono Michi” (Ottmar Liebert, “One Guitar”) and the instant bite of the pluck and the reverberant decay against a deep, dark background.

    As I’ve said, there’s a hint of sweetness to the delivery of the Airist Audio R-2R DAC - and this is most in evidence in the mid-range. Lucid and transparent are also terms that come immediately to mind here. Vocals, particularly female, are present, well articulated, and unexaggerated. There’s no apparent emphasis or reticence. Just a natural, emotive, and evocative rendering.

    Something like “Ellis Island” (Mary Black, “Looking Back”) showcases this sweetness quite nicely. And being a semi-sweet piece in its own right helps to show when this sort of sound is taken too far … and with the RDAC it is not - it’s just where I like it.

    The upper registers are clean, smooth and properly extended, carrying some of that mid-range sweetness forward in a Goldilocks-like “Aaahh … just right” fashion. There’s a palpable sense of air and space and a very honest delivery. If there’s sibilance or harshness in the source material it’ll be reproduced faithfully, without ever exaggerating or exacerbating it. Cranking various pieces by “Heart” or “Julia Fordham” can be a bit of a wince-inducing torture test in this regard but were handled with aplomb by the RDAC.

    Playing a couple of “guilty pleasure” tracks here, specifically, “Buffalo Girls” and “Double Dutch” (Malcom McLaren, “Duck Rock”), through the RDAC shows that it is not going to gloss over faults or harshness in a recording (and you can hear well into the aggressive edits/mix of, say, some of Prince’s works) but it won’tmake them worse either!

    At the opposite extreme, the bottom octaves, while perhaps not the absolute last-word in terms of low-end drive and slam, are only marginally behind the front-runners there and the RDAC certainly isn’t lacking in the bass-department. Playing some more bass-intensive tracks (Beyoncé’s “Partition” or Trentemøller’s “Chameleon”) shows no lack of weight, and excellent texture, speed and articulation. A run through Talvin Singh’s collection “Anokha: Sounds of the Asian Underground” is, similarly, fully satisfying.

    Stage is quite convincing. I only got to test this with headphones but even so the RDAC is capable of projecting a realistically wide stage, and the “sense” of space in a given venue is very well communicated - play something like “Mining for Gold” (Cowboy Junkies, “The Trinity Session”) and you’ll be subjected to a distinct sense of the simple, stark, natural environment the recording was made in.

    Layering and separation are typically strong points of R-2R implementations for me, and the Airist Audio R-2R DAC is no exception. Picking out individual instruments in a complex mix is easy as is tracking the melody while tapping your foot along to the baseline (which you’ll be hard pressed not to do).

    As mentioned initially, there’s a distinctly “pristine” aspect, and a strong impression of “clarity” and resolution/detail that’s evident even on first listening to the RDAC. There’s nothing artificial to this … the detail is real and notof the often-encountered “artificial hyper-detail” found in many D/S type converters. Brushes on cymbals or drum skins, decaying triangle strikes, and so on exhibit are resolved to a level that I’ve generally only found on rather more expensive units.

    Dynamics, both macro and micro, are addictive. “Sledgehammer” (Peter Gabriel) or the intro to “Twist in my Sobriety” (Tanita Tikaram), which are possibly opposite extremes, still both provide graphic illustrations of the ability of the RDAC to simultaneously handle large dynamics while maintaining deftness, subtely, and resolving power with micro-dynamics. Cohen’s typically gravelly delivery, perhaps exemplified in “You Want it Darker”, also serves as an excellent illustration of the Massdrop R-2R DAC’s ability to portray tiny, subtle, variations in volume modulation … which gives his voice a lot of its visceral emotion.

    All of this is set against a deep, dark, velvety-black backdrop. There’s no sense of veil here. Clarity is excellent and, again, “pristine”. Noise on the recording, be it from the tape, the environment (in acoustic recordings), and so on will be fully reproduced, but nothing is getting added to it. I think this is, as with a couple of other DACs I’ve listened to recently, a major factor in how pronouncedly some of the other positive traits are rendered.

    Comparisons to Other DACS

    Schiit Modi MB (via USB) - $250

    For a long time, my go-to reference for an “entry level” DAC has been Schiit’s Modi MB. I still think that it is an excellent unit. The RDAC offers a sweeter presentation, better resolution and clarity and a darker background compared to the baby-Schiit. The difference is enough that I think the RDAC is the better buy, despite it’s $100 higher price-point - if you can swing it, you should in my opinion. The Modi MB does offer a slightly more impactful bottom end, but the difference isn’t huge and is likely affected to a much greater degree based on amplifier pairing.

    Schiit Modi MB (w/ Eitr) - $379

    Adding an Eitr in the replay chain ahead of the Modi MB and driving it via COAX brings things a bit closer together, however I would still place the RDAC ahead - particularly when it comes to clarity, resolution and top-end air/space.

    Chord Mojo - $549

    While the Mojo has a slightly warmer signature, the Massdrop unit exhibits better bass texture and weight/slam combined with a notably smoother higher treble rendering. Raw resolution is similar in the mid-range, but I prefer the tone of the RDAC. And the Arisit Audio DAC conveys a better sense of air and the general ambience of the venue with the acoustic recordings I tried.

    Bifrost MB (w/ USB Gen 5) - $599

    Next to Bifrost MB, the RDAC continues to deliver a blacker background, the sweeter presentation and there’s still a slight sense of better clarity out of the RDAC. But now resolution and micro-dynamics are largely on par and the Schiit DAC’s low-end drive is still slightly superior. Again, not a big difference, but absolute bass-heads might prefer the Schiit unit - depending on what amp they’re pairing with.

    iFi Audio Micro iDSD Black Label - $599

    Not a perfect comparison, as the Micro iDSD BL is not just a DAC and, as such, presents interesting variations in perceived value based on how it’s going to be used. AS a pure DAC, however, the smoothness of the Micro iDSD seemed to take a little of the edge off brass and discordant piano (that’s a negative, as far as I’m concerned) compared to the Massdrop DAC.

    The mid-range delivery between these two units is similar in terms of liquidity and resolution, though the “sweeter” delivery from the R-DAC works better for me without coming across as specifically romantic.

    Bass is rounder and fuller out of the iFi unit, but this came at the cost of a slight loss of texture into the mid-bass vs. the RDAC. I’d say quantityfavors the Micro iDSD and qualitythe RDAC.

    DENAFRIPS Ares - $650

    The Ares has slightly more weight in the bottom end than the RDAC, though perhaps not quite the Massdrop unit’s dexterity with a fast, multi-tracked bass line. Mid-range lacks the sweetness of the RDAC, which may or may not be a good thing for everyone. Transient response, particularly with plucked-strings and rapid percussion, favors the RDAC - as do both macro and micro-dynamics and raw resolution.

    Other Comparisons?

    At this point, it would be fair to say that I’m rather surprised at how high up the DAC-price-ladder the comparisons to the RDAC have already gone, without finding a unit that clearly outperformed it both technically and in terms of overall listening enjoyment.

    How high did I have to go to meet that target?

    It wasn’t until I got to the level of the RME ADI-2 DAC and the Soekris dac1421, both coming in at around $1,000, and both used PURELY as DACs, that I could say that I found something that was, across the board, better technically than the RDAC while being as enjoyable to listen to (I do still like the hint of “sweetness” from the RDAC, however). You should also note that those units give a slightly false sense of the level of price/performance on offer here as they include other features, including capable headphone outputs and, with the RME unit, a very rich EQ and DSP capability.

    If you're reading my "used PURELY as DACs" comment, above, as me having a preference for the RDAC + most of the decent $500 and-under amps I've heard vs. either the RME or Soekris units run as all-in-one devices (i.e. using their internal headphone outputs), then you're correct.

    Summary

    The Massdrop x Airist Audio R-2R DAC is an excellent sounding DAC, with a slightly sweet tone, a distinctly “pristine” and clear delivery and offering very high value. In the month I’ve been listening to it, it has been unfailingly engaging and involving, while continuing to impress on technicalities.

    For the $349.99 asking price, the RDAC is an easy and enthusiastic recommendation.

    Compared to its primary competition, and some units that could reasonably, at least on a price basis, be considered one or two tiers above it, the RDAC offers both higher value and, for me, both better performance and a more enjoyable overall listen. As such I expect it’s going to prove to be somewhat disruptive in the sub-$800 DAC ($1,000 DAC/amp) market.

    Some of that has to be attributable to the Massdrop design and manufacturing approach, which here clearly enables higher than expected performance at lower than typical cost.

    If I was going to build a desktop system right now, from scratch, with an all-in budget of $1,000, then the Massdrop x Airist Audio R-2R DAC would be the DAC I would be opting for. And, unless you wanted to deviate from conventional wisdom and not spend the larger share of the budget on the headphones, it'd still be my recommendation until your DAC budget alone was pushing $800.

    You can be sure that I’ll be joining the drop when it goes live on 6/6.
     
    Last edited: Jun 5, 2018
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  4. 9suns

    9suns [insert unearned title here]

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  5. willsw

    willsw Friend

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    Massdrop making that stack. Wonder how this will compare to the Soekris 1321 for half the price.

    It's a collaboration with Airist Audio, who made the Huron 5 amp. https://www.airistaudio.com/
     
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  6. Torq

    Torq MOT: Headphone.com

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    Technical Details

    Inputs and Supported Formats/Resolutions

    The RDAC offers three inputs - S/PDIF via COAX (RCA) and TOSlink, and USB via a micro USB socket. These are selectable, sequentially, via the “Input” button on the front of the unit.

    The USB input IS galvanically isolated, and the USB input doesrequire USB host power to function as a result. As is typical for isolated USB interfaces, USB power drives the source connection side, and power from the DAC itself drives the DAC side of the USB interface. This also means the unit will show up on your computer even if it has not been powered on.

    This isolation seems to be pretty effective as using the COAX or TOSlink inputs did not yield a useful, audible, difference in quality in my setup. Similarly, trying a variety of USB-to-USB “purifiers” and/or DDCs in the chain did not yield a conclusive improvement. So, while you may experience different results, depending on your precise chain, the USB input is the way to go with this unit in my opinion. Though the option for TOSlink is particularly nice if you want to pair this with a TV/AVR/game console, or are having issues with ground loops.

    In general, though, to get the most out of the RDAC you’ll want to use the USB input. This will give you the broadest range of bit-rate and format support. Officially, USB will let you play PCM up to 24/384 kHz and double-rate DSD (DSD128). With S/PDIF and a native DSD stream you can get to DSD128 and 24/192 kHz for PCM. S/PDIF using DoP will limit you to DSD64 (single-rate).

    Interestingly, and I’ll stress that this is NOT something that is officially supported, nor guaranteed to work, I’ve been able to run the unit at 24/768 kHz and DSD256 (quad-rate) without any issues at all via USB.

    DSD Replay

    As mentioned, the Massdrop x Airist Audio R-2R DAC is natively a multi-bit PCM converter. It can accept native DSD inputas well as via DoP, but that DSD content will be converted to PCM before being fed to the actual DAC ladders.

    Absent completely discrete PCM and DSD conversion stages, all DACs must do some kind of conversion from one of these formats to the other. For example, the PS Audio DirectStream models convert everything internally to DSD before doing anything else, whereas units like the RDAC or the Soekris units convert DSD to PCM.

    What matters most, of course, is what the end result sounds like. Interestingly all of the positive traits I found in the unit are preserved with DSD source material – the same sense of clarity and “pristine” nature of the sound is fully in evidence, and the tone retains the hint of sweetness that I keep going on about.

    In practice, this turns out to mean that the relative positioning of this unit vs. the others I compared it to, remains almost identical regardless of whether you’re feeding the RDAC PCM or DSD. I will say that the low-end of the iFi Micro iDSD Black Label cleans up a little when fed with native DSD content, but at best that brings it on par on that oneaspect and overall, I still prefer the presentation from the Massdrop unit.

    No Snap, Crackle nor Pop!

    It is very common for DACs, even expensive ones, to exhibit nasty pops, clicks, and other noises when switching between DSD sample rates and between DSD and PCM content. So, it’s nice to find that the RDAC makes no utterances during such switches. The unit mutes momentarily during these changes. In general, this is transparent unless you’re skipping tracks. There was no intrusion into the replay of a normal playlist of mixed rate DSD and PCM files.

    Tweaking DSD/PCM Conversion

    You can pre-empt the internal conversion by using something like HQPlayer or Audirvana+ to convert your DSD files to PCM ahead of feeding them to the DAC, using any of a number of more sophisticated routines if you wish. The differences are often audible, if quite subtle, though as an on-going theme with approach I didn’t find any of the them to necessarily be preferableto just letting the DAC do its own thing.

    Don’t be daft and convert to DSD from PCM ahead of sending data to the RDAC, however!

    Power & Power Supplies

    Power to the Massdrop x Airist Audio R-2R DAC is supplied via an external switching PSU rated for 3W @ 5v DC and uses a standard barrel connector. The external nature of the supply means that you can, if you are so inclined, substitute a suitably rated linear power supply instead. Note that all of the listening performed for the main part of this review was performed using the stock PSU.

    Out of curiosity, once the main listening was done, I did try a couple of different LPS units here:

    The Teddy Pardo “Teddy5/3” yielded a small reduction in the noise floor, a side effect of which meant very low-level detail was more easily discerned vs. the stock PSU. Though it’s worth bearing in mind that this particular PSU costs more than the RDAC itself, and the very minor change in performance probably isn’t worth it, nor is it likely to be routinely audible.

    The iFi Power, which is technically underrated for this application (2.5A instead of 3A), did not seem to offer any audible improvement at all. Though this is also an SMPS, just with more filtering and “active noise cancellation”.

    And my lab-grade supply - which gave a larger improvement than the Teddy Pardo unit, but at an even more ludicrous value proposition (several times the price of the RDAC).

    My recommendation is, worry about your headphone and amplifier first and when you eventually have nothing else to adjust, maybe add an LPS to the RDAC!

    Converter Technology

    The Massdrop x Airist Audio R-2R DAC is a 24-bit discrete R-2R (multi-bit, resistor/string ladder) sign-magnitude, oversampling, converter, using low phase-noise NDK clocks and a custom linear phase filter.

    That’s an impressive configuration for a DAC at this level, particularly the implementation of sign-magnitude conversion. This dramatically improves linearity vs. a simple ladder (as much as two orders of magnitude at -60 dB). In listening to other DACs using simple ladders vs. a sign-magnitude implementation it has been my consistent finding that a sign-magnitude approach yields clearly better results - even when compared to much more expensive units.

    Sign-magnitude converters use two separate ladders per channel to improve conversion linearity. With a single ladder, any non-linearity in the ladder winds up being relative to the full-scale signal. A simple R-2R ladder specified with 0.001% distortion actually has increasing distortion in inverse proportion to the signal level, reaching 1% by -60 dB. With a sign-magnitude implementation, as used in the RDAC, the specified distortion remains constant … so 0.01% at 0 dB stays 0.01% at -60 dB.

    Listening Notes

    Critical listening was done with the RDAC being driven via it’s USB input (after determining this was the best way to drive it in my system) via Audirvana+ and Roon. Source material was primarily 16/44.1 FLAC format CD rips, with some native high-resolution content and multi-rate DSD albums to test those capabilities.

    Primary listening was performed via an iFi Pro iCAN and a Woo Audio WA234 MONO Mk2, with some additional amplifiers included for pairing/system matching commentary. Headphones ranged from the HD650 and HD800S to the Focal Utopia and Abyss AB-1266 Phi.

    Direct comparisons were performed in a hardware assisted blind(ish) fashion. Not strictly a fully blind comparison, but a lot closer than simple sighted listening.
     
    Last edited: Jun 5, 2018
  7. purr1n

    purr1n Finding his inner redneck

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    ^ This. Has elements of both DACs.
     
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  8. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    Sounds interesting, will probably buy one out of curiosity even though I do not need any more DACs. The LPS I'm using with the dac1321 should probably work with this too.

    BTW, the product page says the filter is linear-phase FIR.
     
    Last edited: Jun 4, 2018
  9. Elnrik

    Elnrik Super Friendly

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    ... ok, but does it measure better than the Topping D30?

    (Runs for cover.)

    Thanks for the reviews, gentlemen.

    Edit - Reading the 3 reviews, it seems you all agree the DAC sounds quite nice. It's my understanding the precision resistors needed to build the ladder can be fairly expensive, which leads me to wonder if this product is using cheaper units. Will product variation suffer as a result, if true?

    It does seem that @purr1n , @Torq , and @Hands all agree it sounds good. I wonder what would happen if they swapped their units and compared them.
     
    Last edited: Jun 4, 2018
  10. Cspirou

    Cspirou They call me Sparky

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    This is excellent DAC value for the features! I see they have some internals posted.

    [​IMG]

    Looks a bit like a Soekris module. Not implying that it is, just that whatever discrete R2R DAC people make will end up looking similar.
     
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  11. soekris

    soekris MOT - Soekris Engineering

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    Yeah, looks nice, nothing to do with Soekris but discrete R-2R DACs do look alike.... But I did notice the cheap connectors, and even worse, the micro USB connector, my experience with my kids tablets is that micro USB connectors are sensitive tiny crap, there's a reason why I use a full size USB type B.....

    Read somewhere that they use 0.05% resistors, sounds right at that price level, nothing wrong with that by itself, even my lowest cost dam1021 are available with 0.05% resistors .... But the Airist DAC probably don't use the best ones like the Vishay I use, so there could be potential long terms changes in sound quality, could be why they only have 1 year warranty....

    And yes, I might be biased :)
     
  12. Torq

    Torq MOT: Headphone.com

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    Oddly enough, while I personally prefer full-size USB Type B (due to there being a broader array of available high-quality cables that use it, and it being WAY easier for me solder myself), mechanically and electrically the micro USB connector will typically be rated for the double (or more) the number of mating cycles than it's larger brother.
     
  13. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Having recently tested the 1321 against the Modi Multibit, even with custom filters on the 1321, I easily prefer the RDAC.
     
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  14. soekris

    soekris MOT - Soekris Engineering

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    Tell that to my kids :) Could be if you insert and remove them carefully and don't stress the cables....
     
  15. purr1n

    purr1n Finding his inner redneck

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    Too easy to get boogers, dirt, crap, lint smudged on those micro USB connectors. Plug them in and shit begins to accumulate. Maybe in a cleanroom environment is will last longer. I don't like how delicate the micro USB connections are - too easy to disconnect or worse, bend down. Should have gone USB-C. This is the one aspect I truly dislike on the RDAC.

    I wouldn't bother with USB on this anyway given how much better SPDIF in sounds. I'll plug in Eitr and report back. I used the monster Theta Data III, which is like the best transport in the world.
     
  16. Cspirou

    Cspirou They call me Sparky

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    Also it looks like there's enough room for two modules. I wouldn't be surprised if there's a balanced version in the future.
     
  17. Ice-man

    Ice-man Friend

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    So...RDAC/EITR>Bifrost Multibit w/gen5?
     
  18. Vtory

    Vtory Illogical Spock

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    Let me summarize the three reviews:
    • Resolving and clear sound
    • Competent technicality
    • Arguably better head stage than other sub-1k dacs.
    • OS implementation but a bit (good) NOS-ish flavor
    • Forget USB. Use Eitr (or similar things)
    • Solid choice if on the sub-1k dac market
    Correct me if I interpreted wrongly.
    Waiting for the loaner program for this product. Worth checking it out.

    PS. I bet Schiit is smiling now because they can expect higher demand of eitr. (50% joke)
     
  19. Soups

    Soups Sadomasochistic cat

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    I'd hope that if I spent this much on a DAC, it wouldn't degrade in sound quality for a long while!

    I really don't want to crap or speculate on anyone's un-released products or their unpublished specs, but I am curious about your educated take on the possible longevity of these at-the-heart parts. It also probably matters a lot if companies go out of their way to either show or hide who manufactures their resistors or what tiers they're using. So, depending on the quality of resistors used, what kind of stable usage life might something like this DAC or your dam1021 have?

    I'm also curious because I smell more of these "affordable" R2R dacs coming down the pipe, and I think folks ought to be aware of the potential issues down the road, especially if they're getting weak/standard warranties with them. As a Gungnir Multibit owner, it's a consolation here that Schiit will service all their multibit dacs for 5 years.
     
  20. willsw

    willsw Friend

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    One way to add some sugar to that salt would be a MassdropXSoekris dac1X21. Your website still says you're looking for US distribution . . .

    Whenever hifishark tells me in a few months that someone who just bought this to play with is done, I'll probably pick one up.
     

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