Rings of Gold: A Tale of Eight Bifrosts

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Torq, Aug 21, 2016.

  1. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    Let me start by saying that this is not intended to be a review of the Bifrost per-se; there are plenty of those around. Instead, for reasons which will become apparent in a moment, I happen to have all eight current variations of Bifrost available at once and thought it would be interesting/fun to compare them all.

    And then I succumbed to temptation and picked up a Modi Multi-bit, so after this I thought perhaps I’d add a comparison between that, and the various Bifrosts after I was done with this part. I’ll keep that in this thread, but will put it in a separate post.

    Splitting the posts will help make things easier to follow, since I’m frequently an unnecessarily wordy bleeda at the best of times.

    By the way, don’t be surprised if you see a rapid flurry of edits shortly after I post this … despite proof-reading it a couple of times, I will invariably find a bunch of typos, and so on, five seconds after posting that I’ll go back and correct as I see them.

    Anyway, here goes …

    How do we get to EIGHT variations of the Bifrost?

    There are four fundamental variations of the DAC:
    • Original (AKM 4399 D/S DAC)
    • Uber (AKM 4399 D/S DAC but an upgraded analog output stage)
    • “4490” (AKM 4490 D/S DAC and a substantially similar looking analog stage to the Uber)
    • Multi-bit
    The three D/S DAC/analog stage boards are shown below, and from left to right are the original, Uber and “4490” boards (I was too lazy to pull the multi-bit unit apart when I was taking the initial pictures):

    Analog-and-DAC-Boards.jpg

    Combine those with the USB Gen 1 and USB Gen 2 boards, and you have eight possible configurations (2 USB implementations x 4 DAC/analog sections = 8 configurations total); again these are shown below, with the Gen 2 board on the left:

    USB-Boards.jpg

    Those all get plugged into the basic, original firmware, Bifrost main-board, shown here with no boards:

    Bifrost-Motherboard.jpg

    And I have the minimum-of-two Bifrost chassis necessary to make this possible:

    Fronts.jpg

    Backs.jpg



    Why do I have all of these Bifrost parts and two different Bifrost Chassis?

    I bought an original Bifrost, with USB Gen 1 (never used the USB input, as it happened) in February of 2012. I later ordered a self-install “Uber” upgrade, but that was right around the time the new “4490” and multi-bit units were released, and I actually wound up getting a first-article 4490 before it was announced (didn’t know about it until after the announcement).

    My procrastination about having to send my unit in to get it upgraded to multi-bit was the only reason I hadn’t pulled the trigger on that sooner. And when a co-worker expressed interest in my Bifrost/Lyr stack (I use it at my “day job”) I saw it as an opportunity both to get the multi-bit Bifrost without having to ship anything anywhere (and also to upgrade that rig to the Lyr 2 at the same time).

    As the timing worked out, I had my new multi-bit version show up while the old-unit’s buyer was away for a while, so that left me with two Bifrost chassis: my new one with multi-bit and the USB Gen 2 board, and my original with USB Gen 1 and both original and 4490 boards.

    An idle thought/post on another site about maybe finding a cheap Uber board and comparing all the units lead to @crazychile very kindly sending me his old Uber board. So many thanks to him for making this possible!

    Evaluation Configuration:

    Listening was performed via my Ragnarok, using HD800S, Abyss and LCD-4 headphones. Source feeding the DACs was Roon via an Auralic Aries. All music was lossless PCM, stored in FLAC format, mostly 16/44.1 KHz CD rips and a smattering of high-resolution files for good measure.

    While I don’t normally use USB for audio (except from my laptop/iPhone/iPad when I travel), I obviously used it here as part of what I wanted to do was compare the two generations of USB board.

    No USB widgets, re-clockers, conditioners, filters or other such were employed (tried a few on a lark, but never found a difference coming out of the Aries).

    I also did some comparisons with the optical and COAX inputs while I had both chassis available.

    On the Bifrosts specifically, and why two chassis are required here:

    As anyone vaguely familiar with the Bifrost knows it’s an upgradeable unit. In the case of the AKM 4XXX based units, and either of the USB boards, you can run them in any combination and swap them around as you see fit.

    The multi-bit board requires different firmware on the Bifrost, however, which is not offered as a field upgrade. And, once upgraded, you cannot then run the AKM 4XXX boards with it.

    This means that, with just two Bifrost chassis available, I can only directly compare an AKM 4XXX configuration to the multi-bit unit. From that it follows that my comments on the differences between the D/S boards, compared to each other, are based on listening to them in succession – with a few minutes in between to swap the boards around.

    It’s also worth noting that I do not have the parts available to put the two different USB boards against each other directly while still using the same DAC stage. So any commentary on the differences between USB input performance is based on the same approach as comparing the D/S boards to each other (i.e. comparing notes and listening in succession).

    Evaluation Methodology:

    "Methodology" might be a bit of a stretch ... there's nothing particularly scientific here; I matched levels and did both sighted and blind listening across a reasonable selection of music of multiple genres.

    The blind evaluation was assisted using a little box (I’m going to refer to it as BTAB, for Blind-Test-Assist-Box from here on – maybe I’ll come up with a better name if I ever offer the thing to others) I’ve been putting together that performs the level matching, provides two outputs from a single input, randomly switches sources under a couple of different models, and records the listener’s choice as to whether they hear a difference in sources or not. I’ll talk more about the specifics of that “box” in a subsequent post, but for now I just want to clarify my intent with it …

    And that intent is emphatically NOT to deliver a formal double-blind/ABX test (without a witness I could easily misrepresent the results anyway), nor to prove, or disprove, that DACs all sound the same, but simply to help eliminate as much expectation bias as I can do easily.

    Excepting possible issues in the implementation of this box, which is still very much a prototype, other factors that make this less than ideally scientific (which, again, I’m not striving to be – nor am ever likely to) include the fact that I absolutely know I’m listening to two different units and am expecting differences.

    Random Aside:

    Remember I said I could be an unnecessarily wordy bleeda?

    If you haven’t fallen asleep by now you will no doubt be realizing, at this point, that I really wasn’t making that part up …

    Results:

    First, I’m going to say that I love the Bifrost. I’ve had one since 2012. I used it with a Lyr and, first, HE-500 and then LCD-2.2c, for years before feeling compelled to upgrade. I’ve always enjoyed listening to it. I’ve taken advantage of the upgradability, and if I wasn’t so impatient, and had such a tendency towards procrastination, I’d have gotten three upgrades out of that platform by now rather than one (two, if you count buying a new one to get to multi-bit with less hassle).

    Not bad for four and a half years!

    I think it’s a great product that competes happily quite a way above its price-level and delivers a wonderfully musical experience with no fuss and in an easy-to-live-with package.

    I digress …

    Original:

    I’m more familiar with this version, and indeed this DAC as a whole, from a headphone perspective, than any other, having lived with it as my primary headphone-rig DAC for three years (my recently renewed focus on headphone listening vs. my speaker system is a result of major life changes … all positive, but, still … major changes … and I’d simply not felt compelled to upgrade until late last year).

    Familiarity is a funny thing, however, and it was not hard to decide that while less “sculpted” in terms of delivery than I now find the “4490” to be, this was very easy to identify with the right tracks … and I prefer the “4490” in most cases.

    Bright, sharp, horn and trumpet blasts can be a little uncomfortable here and I don’t find the top of the piano to be that convincing when played, shall we say “overly enthusiastically”, and I found a little edginess when dealing with starkly presented female vocals.

    One of the more emotionally communicative pieces I enjoy, is Tracy Chapman’s “Behind the Wall” in her acapella performance. A somewhat strident aspect to this when played through the original Bifrost board distracts from the natural emotion of the piece and snaps me back out of the music and into a “listening to a recording” mind-frame.

    Having heard all of the Bifrost versions to date, I would make no bones about upgrading to one of the newer variants. Even at their original prices, they all take an excellent DAC and elevate it.

    Uber:

    It might not measure as well as the “4490”, but if I was going to stick with the D/S boards and not go multi-bit then this is, simply put, my preferred version of the D/S Bifrost.

    The original Bifrost could, for me, get a little uneasy with louder high-frequency information – making sharper or discordant brass tones a little too edgy. With the Uber board installed this, admittedly minor, tendency was gone. I also found the top octave of the piano, played very aggressively, and again with a musically discordant outcome, was improved over the original (not that this comes up a lot in music, but I have a thing for piano reproduction).

    Dynamics and transients are notably improved over the original, to which I’d attribute the slightly “faster” sound (not that I’d suggest the “original” was, in anyway, “slow”) particularly with intricate electronic “percussion” (some “Infected Mushroom” stuff, for example). Really quite impressive here.

    Additionally, I found that the Uber variant did a better job of keeping the bass natural and eliminating what I have tended to perceive as a slight hump in the lower/mid bass octave around what I’d guess as being 80-120 Hz or so (and that guess is somewhat informed by a brief and impromptu, test in my speaker system). Now, I’d also guess this thing measures ruler-flat, but for whatever reason I hear some slight emphasis here on the original that I don’t get on the Uber.

    I’d have to be able to listen to them directly against each other, rather than pausing to swap out boards, to have more conviction in what I’m hearing there, mid-bass wise, but that’s how I’m going to call it for now.

    At the end of the day, and limiting things to the D/S boards, I find this the most resolving version of Bifrost as well as the most musical and natural, but I’ll come back to that in my thoughts re: the next D/S board …

    4490:

    Most of the best attributes of the Uber … but despite my first, very positive, impressions of this upgrade as a whole (no doubt influenced by an unhealthy helping of expectation bias), over time I’ve found the rendering of the lower octaves to exhibit some bloom and an overall general sense of slight artificial warmth, or sweetness to the sound.

    If I was listening predominantly on a system that was lacking a little in the lower registers and/or I was a bass-head, then this would be the Bifrost I would lean towards.

    It has lots of slam and some easily-discerned emphasis down-low, sometimes to the point of feeling a bit artificial. And then it’s warmer than I’d expect. While this can make for a very lovely listening experience, it can be a little much when paired with a warmer/richer amp and/or headphones that tilt towards rich, dark or deep.

    With HD800S it’s actually rather nice, but less so driving the Abyss or LCD-4, where the emphasis in the bottom end tends to intrude into the lower-mids and leave things slightly confused, or, perhaps, shadowed is a better word (I’d say “veiled”, but that’s not really what I mean, and I’m not quite sure how to express the effect in a way that would mean anything to anyone else).

    I think low end detail and articulation suffer a little here compared to the Uber, and the impact on the lower-mids means that, while initially enthusiastic about this version of Bifrost, overall it’d place behind the Uber version for me.

    There are definite plus points here though, and not just for bass-heads.

    I do find the 4490 to be particularly beguiling with piano … at least for a D/S based implementation (in other evaluations piano is something I’ve consistently preferred through multi-bit/R2R DACs). And with some female vocals, including Julia Fordham and Mary Black, I’ve gravitated towards the 4490 as well (again, sticking to D/S based units).

    It is very musical.

    Not necessarily completely natural, but musical nonetheless.

    The AKM 4490 is probably the most distinctive converter I’ve heard; in that across multiple implementations I come across the same basic character … and I’m not normally one to ascribe specific tonality to a specific IC, and where I have it has often been down to the filter selected.

    It’s more typical for me to have issues with some DAC ICs, which may be down to the chip, or the nature of the implementation that tends to follow that specific IC. For example, excepting some bass-wooliness-issues with PCM-1704 based converters, other DAC chips that I’ve “not gotten along with” have been less specific and have been things that just “didn’t sit right”, regardless of implementation (e.g. CS4398, various ESS builds, and now the AKM 4490).

    Maybe this is down to AKM’s “velvet sound” tuning … rather than striving for simply neutral – I don’t really know. But based just on listening, it’s less to my taste, in my current system, than the 4399.

    Multi-Bit:

    For good reasons, or bad, and with, or without, obvious sources of bias, I seem to strongly gravitate towards multi-bit solutions. That’s been apparent in my quest to find a DAC that I like more than Yggdrasil.

    In short … if you have the means, and are looking at Bifrost-level options, then … just buy this.

    It convincingly out resolves all of the other versions (one wonders if it would do so even more convincingly with a discrete analog stage instead of op-amps). Tonality is, for me, across the board better than any of the D/S variations. Dynamics and transients are clearly improved.

    Rendering of piano is beautiful (I know, I keep going on about the bloody piano), and perhaps my favorite delivery other than Yggdrasil (Gungnir D/S isn’t as good, and Gumby might be a bit to warm, or perhaps wet, for me, in that regard as well).

    No hash, no harshness, but lots of detail, that doesn’t come across as being bright nor artificially detailed … unlike, say, the Auralic Vega.

    I find the timbre here to be notably better than any of the other variants and instrumental separation is excellent (you’re not going to confuse a violin and a viola, for example, unless you’re not sure how they sound to begin with).

    While I would place the overall performance of Gungnir multi-bit closer to Yggdrasil, I find Bifrost multi-bit to be a little closer to Yggdrasil in terms of raw neutrality. It’s a bit less musical, perhaps, as a result (don’t ask me how that makes any sense), but raw character seems closer.

    If I was listening to the Bifrost D/S variants in isolation and/or didn’t have Yggdrasil as my primary converter, I might not have noticed the slightly artificial sheen that they put over brass, or cymbals, and that is completely gone with the multi-bit version.

    Much like Yggdrasil, the multi-bit Bifrost is able to render detailed cymbal brush-work with genuinely surprising resolution. To the point where, if you’re paying attention, and the rest of the chain is up to the task, you can hear a few wires on a brush touch the instrument before the body of the bundle makes full contact … “tt-ssshhhh” instead of just “ssshhhh” (yes I suck at putting sounds into letters or words).

    Another interesting factor, which I only looked at (or listened to) briefly, was imaging. I ran the units in my speaker system very briefly … and here the multi-bit is FAR better than the D/S units at projecting a proper soundstage. Palpable, three-dimensional, easy to visualize the placement of any given section or instrument, and able to properly project the left-to-right spatial progression of notes keyed on a piano (there I go again)!

    On bass …

    Compare this to the 4490 and it seems a bit shy in the bottom end. Listen a bit longer, and it isn’t. While I’m not a Beyoncé fan, “Partition” has a useful bass element for comparing extension and articulation. So does “Chameleon” (Trentemøller). Play these tracks, next to something like “The Rat” (Infected Mushroom) back to back on the 4490 and multi-bit and suddenly the 4490 seems overdone and the abilities of the multi-bit version come to the fore. Sub-bass is very present and articulation, dynamics and slam also favor the multi-bit.

    And, finally, at no point during my listening, even via the BTAB did I have a difficult time discerning the multi-bit Bifrost from the D/S versions. And compared to the 4490 I was correct ~90% of the time. Though I have to say I’d attribute that more to the admitted tuning of the AKM 4490 by AKM engineers than anything else.

    Interfaces:

    USB Gen 1 vs. USB Gen 2:

    The most striking thing I noticed here was that between the two USB input boards I noticed a bigger difference in their effect with the AKM 4XXX D/S configurations than with the multi-bit version.

    Why this should be I am, obviously, not entirely sure. I could speculate that it might be due to D/S being more sensitive to jitter than multi-bit, or might be down to more sensitivity to noise, or it could be something random or unexpected like the discrete analog stages on those boards being more susceptible to noise from the USB receiver/circuitry than the op-amps used on the multi-bit board.

    At some point it’d be interesting to re-stage that test with two multi-bit chassis and the two different USB inputs via the BTAB and see if there is, in fact, any reliable difference that I can detect there, in my setup.

    I can’t claim, in my listening here, that there were really specific tonal or resolution differences between the two different USB interfaces. In general, the differences were quite subtle and didn’t really become apparent without more extended listening. And in those cases it was generally more a case of fatigue setting in faster on the earlier version.

    If I had a USB Gen 1 – I wouldn’t spend the money to get a Gen 2 upgrade. If I was using a PC, I’d buy an S/PDIF interface card and ditch USB entirely. With a Mac, I’d just switch to optical and spend the difference on a decent-but-relatively-inexpensive, glass, optical cable (e.g. Lifatec).

    If you’re buying new, then you don’t have to think about it … you’re getting the Gen 2 interface anyway. If buying used, I’d take a USB Gen 1/Uber over a Gen 2 original or 4490, but Gen 2 is seemingly better all the same.

    USB vs. S/PDIF (Optical and/or COAX):

    While BTAB can switch outputs on the fly, not all DACs switch inputs in response, and even if they do (e.g. Mojo), they don’t do so in a manner that isn’t obvious (brief muting). And Bifrost requires you to hit the button on the front to switch inputs, so testing solo, as I did, there is not even a hint of “blindness” to what I heard here.

    And I’ll state, for the record, I’m really not big on USB as an audio interface, so, again, I’d state there’s probably an unhealthy level of expectation bias in my findings here (though they’re generally in line with my overall experiences for different audio interfaces).

    My preferred interface for DACs runs in the following order:

    AES/EBU XLR > TOSLINK >= COAX BNC >= COAX RCA > Wet String* > USB​

    And the short version of this already unnecessarily-wordy (see … SEE!), sub-section, is that the S/PDIF inputs to the Bifrost sound, to me, across the board better than the USB inputs. And that’s coming from what’s supposed to be a pretty decent, femto-clocked** USB output on the Aries.

    Resolution/detail and general listenability are, for me, better using the S/PDIF inputs. Fatigue sets in much later, if at all, timbre is improved, and any sense of higher-end sheen seems to drop away when driven optically (and via coax, but I tend to go with TOSLINK for the higher degree of galvanic isolation).

    (*I may, or may not, be joking).
    (**Quantum-equilibrium-thermo-bollocks***).
    (***Microsoft Word 2016 for OS X has “bollocks” in its native dictionary!).


    Summary:

    I’d put Bifrost Multi-bit clearly at the head of the pack. I think it hits well above its price level. The more I’ve listened the more I find I prefer it to, say, Chord’s Mojo, which I also find performs at a much higher level than the price might lead you to expect.

    You’re probably at 80%, maybe 85% of Yggdrasil’s performance here. And even then the rest of the chain could likely mask the differences.

    For simply listening to music for pleasure, and not trying to find minute differences, I’d rank the Bifrost units as follows:

    Multi-bit > Uber >= 4490 > Original

    For those that want bass slam and quantity over articulation and sub-bass rendering/extension and, well, everything else, you probably want a 4490 … but that’s not me.

    And then for raw value, it’s going to be hard to beat a sensibly priced, used, Uber w/ no USB.

    But, then, Modi Multi-bit really complicates (or, perhaps, simplifies) that end of things. However, that’ll have to wait for a follow-up post …
     
    Last edited: Aug 22, 2016
    econaut, Mshenay, Lenroot77 and 63 others like this.

  2. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    Modi Multi-Bit vs. Eight Bifrosts

    This is going to be a much shorter post than the actual Bifrost-to-Bifrost comparisons, which is one reason I decided to just reserve a spot in this thread for it rather than start another one.

    Testing was done using the same chain and play list as with the Bifrosts and in this case the BTAB thing was really useful, for me, in trying to keep this as honest as possible. I left the Bifrosts configured with the Gen 2 USB board for this, but otherwise split my testing between USB and S/PDIF.

    MOMBY vs. Bifrost D/S (Original, Uber & 4490):

    Modi multi-bit made relatively short work of the D/S Bifrost variants for me. I’m not sure that that would have been the case had I not just come of some extended comparisons of the Bifrost D/S vs. multi-bit DACs. By which I mean it likely would have taken me longer to come to the same conclusions if I hadn’t already established some baselines and gotten a consistent enough feel of which Bifrost unit was which.

    So, I’ll save some time and summarize Modi multi-bit vs. Bifrost D/S as being, for all intents and purposes, the same thing I found with the D/S and multi-bit Bifrosts.

    MOMBY vs. BIMBY:

    The short version is that, with the vast majority of music I sampled with, using short-passages of music (15-20 seconds) I was simply not able to reliably discern a difference between the Bifrost MB and Modi MB.

    There were a few cases where I was able to tell them apart, but they were few and far between and in very specific ways – in fact I boiled down to consistently being one or two factors … namely either resolution/detail and/or sense of space to the recording.

    A couple of examples:

    • Cowboy Junkies’ “Mining for Gold” (The Trinity Session) gave me the sense of more space around the performers with Bifrost MB.
    • With Saint Saens, “Introduction et rondo capriccioso, For Violin and Orchestra in B Minor, Op. 28”, Bifrost MB made the breathing of the violinist more audible and there was more texture to the passage of the bow over the strings, as well as rendering a more open sense of the ambient acoustic.
    It took entire songs, sometimes played more than once, and listening as critically as I can, to make those determinations, and even then it was not totally reliable (though it got easier with repetition). And, as a result, while I might say that Bifrost MB has slightly better resolution/detail … I don’t know anyone that actually listens to music in a way that I think would be necessary to make it very relevant.

    Maybe a more reliable differentiation will emerge with extended listening sessions – I’ve not had the Modi Multi-bit long enough to comment on that yet.

    Mandatory Random Aside:

    It was interesting for me to note that, looking back on my test logs, I only ever successfully told Bifrost MB and Modi MB apart using either the Abyss or the HD800S. I did not record a single instance of discerning a difference (rightly or wrongly) through the LCD-4.

    I suspect that says more about the strengths of the various headphones than it does anything about the DAC itself.

    Summary:

    So, at the end of the day, for me:

    • If I was going on sound-quality, I’d have to take Modi Multi-bit over all of the D/S Bifrosts.
    • And then whether I went Modi multi-bit vs. Bifrost multi-bit would depend on where I was going to use it and what I was pairing it with. I’m sensitive enough to aesthetics that I would, absolutely, opt for Bifrost multi-bit to go with Lyr/Asgard/Valhalla – but that would be an aesthetic, rather than sonic, call.
    If I had to put these things in performance order:

    BIMBY >= MOMBY > Uber >= 4490 > Original​

    If price/performance enters into it though:

    MOMBY > BIMBY > Uber > 4490 > Original​

    And then, since it’s already been asked … and while I don’t think it’s necessarily a very useful mechanism for comparison or summary, I’d put MOMBY at 95%-or-better the performance of BIMBY – at least for listening to music.



    What a bloody marvelous little device!

    Modi-and-Vali-2.jpg

    It is now paired with a Vali 2 in my bed-side setup (fed via a Sonore SonicorbiterSE and Roon) … and those pair really well. Hard to believe just how close they come to the BIMBY/Lyr 2 I use at my day-job, and for less than half the price. Some really serious performance and a high degree of musicality here!
     
    Last edited: Aug 22, 2016
    econaut, Mshenay, Lenroot77 and 42 others like this.
  3. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    BTAB – Blind-Test-Assist-Box:

    I’ll post a dedicated thread on this at some point, if there’s interest, but the “Blind-Test-Assist-Box” (BTAB), apart from desperately needing a better name/acronym, is a little thing I’ve been playing with for a few months now.

    It’s NOT intended to settle any arguments in the objective-vs-subjective vein, at least not from my perspective (I’d rather listen to music than debate those points), though how you might use it is, if I get to a point where it’s something “not just for me”, is, of course, up to you.

    All it really is a “sensible”, simple, tool to more easily/reliably (urk!) facilitate blind and ABX testing for source components.

    While there are certainly tools that enable such things today, they are generally software-side solutions, which aren't very useful if the source you want to compare isn't a computer-based player and, in the case of the most readily available (say, Foobar2000 with an ABX module), it's a Windows-centric thing.

    It also typically forces you to have USB somewhere in the audio chain as most computers don't have any other way to talk to a DAC.

    Anyway, BTAB does a few things:

    Digital Distribution Point:

    Feed it a digital input and it'll give you two outputs of the same signal, allowing you to connect to two digital devices at once and have them playing in synchronization form the source. It allows you to adjust timing between delivery to those two sources to permit overcoming any latency from internal buffering/re-clocking schemes as needed. You don't have to use this stage ... you can just use the analog inputs (see next point) instead if you prefer.

    There are two outputs each for AES/EBU XLR, TOSLINK, COAX and USB (added in the last week). So you can compare like-interfaces, or differential ones.

    And it can be set to switch which digital output-type it drives instead of switching sources if you like. This is intended to allow comparison of different interfaces (e.g. AES/EBU vs. USB) on the same DAC. It is also likely to be of marginal usefulness, since not all DACs will switch which input they’re observing based solely on presence/absence of a signal on one of them (Bifrost doesn’t, for example). But it was a cheaper software feature to add “just in case”.

    Analog Inputs & Level Matching:

    It can take two stereo analog inputs and provides a push-button way to automatically level-match them to within 0.1 dB (quite a lot better than you'll manage by ear and beyond the realistic capability of many SPL meters), and then provides a single, switched, output to an amplifier.

    Multiple Comparison Modes:

    Right now it provides for a couple of comparison modes, with a simple control to allow the user to indicate when they hear a difference.

    One mode simply repeats a selectable passage of music ... you mark a start and end point, which it stores in an internal buffer, and then it'll repeatedly play that while switching sources. The other simply passes through whatever is coming from the source and switches sources randomly there. This allow you see if differences are detectable in-stream or between repeated passages. Then there's an option to mute between switches or make the changeover seamless (at least I think it’s seamless).

    It logs what source is playing and when, records when the user indicates they detect a difference, and then gives you the data so you can analyze it from there.

    Lions and Tigers and Random Numbers:

    Switching is driven by a proper hardware random number generator rather than a pseudo-random software one (e.g. Mersenne Twister), and within certain constraints you can substitute a different device there (which comes from me not having settled on which RNG I wanted to use when I first got things running).

    Other Odds and Sods:

    If I have the prototype in a state I can bring with me (and that won’t attract undesirable attention from those lovely security types), and assuming I can make it at all, AND assuming there’s even any interest in the thing, I’ll drag it to LA with me in November.

    And then, once it’s done, I will probably throw it up on a crowd-funding site and see about building as many units as there is interest in (again, if, indeed, there IS any interest!). After which I’ll probably release the software and schematics for those that want to build/mod the thing themselves.

    Please don’t take this as being either pro, or anti, subjectivist or objectivist stances. It’s a silly, fun, little project for me and, even as an engineer (among other things), albeit not in the audio space, I’m highly disinclined to engage in subjective/objective debates … especially when there is music to be enjoyed, Scotch to drink, and my lovely fiancé sitting in the other room wondering just what the smeg I’m doing in here on a Sunday night, typing frantically and looking like a bastardized Cyberman … (it’s a Doctor Who/Abyss thing).
     
    Last edited: Aug 21, 2016
  4. jexby

    jexby Raised by Carthusian Monks - Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    1,555
    Trophy Points:
    93
    Location:
    CO
    very well done, and clearly Wet String is the anti-usb buzz word now!
    cheers,
    |{
     
    Torq likes this.
  5. Psalmanazar

    Psalmanazar Friend

    Friend Banned
    Joined:
    Sep 27, 2015
    Likes Received:
    1,599
    Trophy Points:
    93
    Great comparison! Which goes the best with beer though?
     
    Torq likes this.
  6. Madaboutaudio

    Madaboutaudio Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    558
    Trophy Points:
    93
    Location:
    Singapore
    @Torq,

    interms of a rough number percentage, how close sounding do you rate the MB Bifrost to the Yggdrasil?
     
  7. Pyruvate

    Pyruvate Friend

    Friend
    Joined:
    Sep 29, 2015
    Likes Received:
    1,018
    Trophy Points:
    93
    Location:
    Here
    Awesome work! Can't wait to see the modi comparisons, it's going to be darn interesting to see how it stacks up to its older sister.
     
  8. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    Well ... are we talking English beer or American?

    Assuming it's not a trick question! In which case, I'm going with "red-heads"!
     
    scuba8, SpaceLaser and Psalmanazar like this.
  9. jowls

    jowls Something related to poop - Friend

    Friend
    Joined:
    Oct 3, 2015
    Likes Received:
    1,631
    Trophy Points:
    93
    Location:
    Australia
    I would be interested to know where @Torq places Gumby and Mimby as a percentage of Yggy too. It would be a useful tool for people planning their upgrade path...
     
    Madaboutaudio likes this.
  10. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    For what such numerical approximations are worth, I'd say it reaches 80%, maybe 85% of Yggdrasil's performance.

    To put that in perspective, I'd put GUMBY (though I'm rather less familiar there) at 90% or so ...

    Both numbers assuming critical listening ... if we're just talking in terms of recreational musical enjoyment, those numbers might move up a bit. I've now heard all (and own three) of Schiit's multi-bit DACs and they are, unfailingly, musical and entirely enjoyable.
     
    landroni, Psalmanazar and jowls like this.
  11. Madaboutaudio

    Madaboutaudio Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    558
    Trophy Points:
    93
    Location:
    Singapore
    Was still reading his lengthy post when I posted the % question, thanks jowls for the quote.

    @Torq, do you mean the % for yggdrasil Single Ended vs MB biforst SE?

    What about % for Yggdrasil balanced vs MB biforst SE?

    Wonder what % would the MB Modi fall into.
     
  12. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    Thanks!

    Was fun to do!

    Hopefully it is, at least, entertaining and, with a little luck, useful!
     
    insidious meme and Pyruvate like this.
  13. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    I'd put GUMBY at 90% ... again, given the relative coarseness of simple numerical comparisons.

    Though it's fair to say that GUMBY is the Schiit DAC that I am least familiar with.

    I'll try and post my MIMBY/MOMBY thoughts tomorrow and will save the numerical estimation of that until then!
     
    Last edited: Aug 21, 2016
  14. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    Through my Ragnarok I pretty much leave Yggdrasil connected in balanced form. The singled-ended outputs are driving my WA5-LE, so the comparison is SE BIMBY to balanced Yggdrasil. Yeah, I probably should have put Yggdrasil in single ended mode, but so far I find that using Ragnarok single-ended imparts a bigger penalty than using the single-ended outputs of Yggdrasil.

    Modi multi-bit comments I shall save for tomorrow ... ;)
     
    Psalmanazar and Madaboutaudio like this.
  15. insidious meme

    insidious meme Friend

    Friend
    Joined:
    Sep 26, 2015
    Likes Received:
    980
    Trophy Points:
    93
    Location:
    So Cal
    It's too bad you didn't start your epic DAC thread here. Then you wouldn't have tools telling you what to do. :rolleyes:
     
    JK47, Pyruvate and Torq like this.
  16. Torq

    Torq Prob should liquidate and live on a sailboat

    Friend
    Joined:
    Jan 15, 2016
    Likes Received:
    5,437
    Trophy Points:
    113
    Location:
    Seattle, WA
    That is, indeed, too bad.

    For reasons that are unlikely to be made clear in the near future, it is very likely that I'll both continue and, ultimately, finish that particular exploration here though.

    And various, un-named "tools" might well be a decent part of the cause of that! ;)
     
    insidious meme, zonto and Pyruvate like this.
  17. Gravity

    Gravity Friend

    Friend
    Joined:
    Nov 20, 2015
    Likes Received:
    195
    Trophy Points:
    43
    This was a great read, nice job. Are you gonna write something about your RedNet gear at some point? (If memory serves me right you own such).
     
  18. landroni

    landroni Friend

    Friend
    Joined:
    Aug 12, 2016
    Likes Received:
    1,196
    Trophy Points:
    93
    Thanks, @Torq! Excellent review!

    A couple of queries:

    While I've already seen several sources describe Gungnir as somewhat warmer than Yggdrasil (including Jason), @atomicbob has described the Schiit MB DACs as being more 'euphonic' as we move down from Yggdrasil to Bifrost MB. So I'm a tad confused in the above: Is Yggdrasil or Bifrost MB 'less musical'?

    Also interestingly he seems to prefer Yggdrasil for its utmost neutrality, for studio-like work, and Bifrost MB for its being more euphonic, for casual listening.

    Is this the so-called 'digital glare' with D/S that is being discussed elsewhere, whereas R2R DACs reportedly work around this fully?


    I think this bit got lost in rendition....


    My 2006 WordNet contains this entry:

    Code:
    WordNet (r) 3.0 (2006) (wn)
    bollocks
        v 1: make a mess of, destroy or ruin; "I botched the dinner and
             we had to eat out"; "the pianist screwed up the difficult
             passage in the second movement" [syn: botch, bodge,
             bumble, fumble, botch up, muff, blow, flub,
             screw up, ball up, spoil, muck up, bungle,
             fluff, bollix, bollix up, bollocks, bollocks up,
             bobble, mishandle, louse up, foul up, mess up,
             fuck up]
    
    
    Glad Microsoft is catching up.... Maybe support for USB Audio 2.0 is right around the corner. :)


    And again, excellent stuff!
     
    scuba8 and Torq like this.
  19. Cspirou

    Cspirou Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    774
    Trophy Points:
    93
    Location:
    Irvine,CA
    Can't wait to hear about Modi MB vs Bifrost 4490. I think there is a consensus that Bifrost MB > Gumby D/S which really complicates things on a price/quality point. I wouldn't be surprised if you find a similar result.

    Just to complicate things even more, I am positive that the Bifrost main board has been silently revised as well. Just look at the pics of the internals at Schiit.com and you will see that the power supply has two bridges as well as an extra tap for the transformer.
     
  20. crazychile

    crazychile Friend

    Friend
    Joined:
    Jan 19, 2016
    Likes Received:
    251
    Trophy Points:
    63
    Location:
    Eastern Iowa
    Great write up Torq! Thanks for taking the time to compare all of these.
     
    Torq likes this.

Share This Page