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Schiit Modi USB DAC

Discussion in 'Dedicated Source Components' started by barry s, Dec 12, 2012.
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  1. x838nwy
    Well, that's fine with me. I didn't think it would make a difference either. I bought the cable direct from Tellurium Q on the 30 days return thing and seriously I told them that I will most likely be sending it back cos I did't believe in this crap. Made a believer out of me.
    If you're willing to investigate, I think there are many places that offer a no-questions-asked return on cables. Start with about 100USD budget and see if it makes a difference or not. Try something like a WireWorld cable or Pangea something that isn't obviously just another free cable dressed up. If you notice a difference, another avenue of system tweaking opens up for you, if you don't then you can send it back and never have to worry about USB cables ever again and leave idiots like me to it.
    On another note, I'm here listening to the Modi from my MacBook Pro -> USB cable -> Modi -> (the tiny cable from BJC - MS1?) -> X-Cans V2 -> Grado SR225 and I've concluded that there's next to no difference between the BJC little cable and the AQ Evergreen (which came free with something I bought a while back). But the change between the UV7 and StraightWire is a quite a bit more pronounced than swapping the RCA's. Again the UV7 is thinner-sounding and the SW this time more mellow and more boomy and bassy the difference is fairly small, much less pronounced than with my Lehmann Linear last night but it's there.
    Now, science says that the USB cable doesn't really carry whatever signal eventually translates to a bass note or a voice differently, but some cables do sound different to me while some don't. I tend to think it unfortunate since I have to spend money on usb cables but then again, some people buy designer clothes to make themselves feel better. Some feel that giving to charity gives them good karma and some believe in an afterlife. I happen to feel that USB cables make my dacs sound different. Which is perhaps just as reasonable seeing that I actually hear the difference.
    Regarding the design of the USB interface being filtered, isolated, fortified with vitamins etc, I'm sure the Schiit team specially Mike Moffat, knows what they're doing and more. I'm sure no dac designer on earth is going to say "well, we sort of left it all crappy cos we couldn't be ar$ed". The same can be said for output and input stages both digital and analogue on all equipment - they're all designed as well as possible (for the designer) to a given budget/margin. But that doesn't stop interconnects doing things to the signal, does it. So why should USB cables all sound the same just because it's all filtered up and all that. Again, I believe in what I hear. Some don't hear the same as I do and that's fine with me.
    Final note, I've paid for all these cables as I actually needed all of them in different places. I bought the UV for a bit of an investigation and since it was also at a good price. The Pyst I bought at the same time as the Modi and the Black Diamond I got cos I was impressed with the Black but needed a longer cable. I still have a fair few days left on two of them to send back if I want to so I'm not trying to justify spending my money on any of the three. Just wanted to share what I found.
    p.s. It seems very strange to me that while it's so very easy to try different USB cables*, not many people do. I live in Thailand and it's bloody hard for me to get thing back and forth and still I can try them for like 2 weeks or something at a time. You guys in the US should do this more. 
    * - easier than RCA or XLR interconnects as there's little possibility of blowing things up or getting strange noises from your headphones.
  2. PanpandaChan
    I'm just going to address this real quick because I dont want to get into a whole general cable argument.
    By "filtered" I mean that the POWER from the USB is being filtered. USB cables have 4 wires: 2 pairs, one +/- pair for data, one for power.
    Power can indeed be "dirty" or "noisy" depending on the power supply used in the computer and the circuitry that leads to the USB output.
    How much of an effect does that have on audio quality from a DAC? I'm not sure.
    However, as for the data pair, it carries the 1s and 0s transmitted by whatever audio driver on your PC.
    A 1 is a 1 and a 0 is a 0.
    If some kind of interference happens and a bit gets flipped (1 into 0 or vice versa) things will just sound entirely wrong.
    Its not as subtle as a change in sound signature, but rather you'll hear a different sound completely.
    This is because the hardware in the DAC takes chunks of these 1s and 0s (24 if its a 24bit signal, etc) and translates each chunk into an analog output (the sound).
    Now at that point, cable quality can change the sound signature. I saw a lot of this in the Philips Fidelio X1 thread because the stock cable had unusually high resistance, which messed with the sound.
    Visit home theater/AV forums and you'll see similar discussions about HDMI cables, and how the situation is no longer the same as the past of Analog composite cables. Its a similar situation as this.
    In conclusion though, you are right about people who spend a ton of money on designer clothes and whatnot just because they want to. And I'm not saying you're wrong or stupid for buying expensive USB cables at all. Its up to you what you want. I just wanted to share my thoughts about it.
  3. x838nwy

    In the words of wiser men than i:

    Again, there's a school of thought that says it's all 1's and 0's. Then there's what these folks think. I think if usb audio were a religion, Gordon Rankin would be an equivalent of Moses or something.

    I don't own any gear sold by these three, unless you count the dragonfly which is not a cable but was designed by Gordon, iirc. And an AQ evergreen rca if you call that an actual upgrade from a freebie cable. But yeah, i'm not fortunate enough to own any wavelength stuff and i chose a pwd2 over the ayre usb dac. There are times when i wish i hadn't, but mainly for practical reasons.
  4. x838nwy

    Here also. Part 2.
  5. PanpandaChan
    I took a skim of the articles, and from what I understand, the issues that they list as possible with digital audio signals and whatever equipment you use mainly relates to the timing of the bits and how the many components in the DAC translates it.
    The article seems to focus on how the same chunk of 1s and 0s can be translated to analog differently depending on your DAC, which is a valid point.
    The only issue raised about cables which I see is the talk about a company who made a 50ft USB cable.
    As far as I know, the "standards" for the USB cable specifies a max of 5m, which would only be 16.5ft.
    So okay, if someone makes an obviously bad cable (and it is obvious because it doesnt follow standards) then bad things will happen.
    The cable was too long, and thus messing with transmission rates of data, which does screw up the standard that the DACs are likely designed to work with.
    I dont see how else cables can affect audio quality though.
    As long as the cable carries the signal appropriately, within the USB standards, it'll sound the same.
  6. Netrum
    I agree with your conclusion sir.
    What we are seeing here is called the "Placebo" effect.
    You buy something so expensive that you convince yourself it has to sound better.
  7. x838nwy
    If you have some time, please re-read the articles. They're very interesting. In the context of our conversation, the relevant facts to your reasoning can be paraphrased as:
    1.) The signal consists of 1's and 0's and
    2.) as long as all the 1's and 0's get there, the information is perfectly transferred.
    3.) Importantly, you appear to say that if the cable itself cannot and does not drop a 1 or a 0, then we're fine.
    What the guys interviewed said are the following as relevant to our conversation:
    So, what is being sent over the cable is basically square waves at high and variable frequency. I consider anything from the USB-A jack on my cable as a "receiver side" and as a cable is basically a transfer function to the signal, it is possible that it can affect the signal's rising and falling edges, it may cause ringing, slewing, etc. and it may do so differently at different frequencies/patterns of 1's and 0's. Basically, if you believe that an analogue cable can have and effect on your analogue data, then in that sense I see no difference between it and what goes into the usb cable. Remember that a step change is simply a sum of sine and cosine waves at various magnitudes going down a cable at the same time. I'm not a cable designer and I have no tools to measure or publish the results, but from what I gather, the signal is not as robust as many think and is not a lot different from a high freq. analogue signal.
    To summarize, your (1) is a useful visualization/idealization but not quite what really is transmitted. Instead, it is what is re-constructed at the DAC chip from a high freq. analogue signal. (2) is not so true as the timing of the signal is important also. Its waveform also appears to be important (although the interviewees did not make this very clear). And (3) is not completely true as Gordon did make it clear that one rarely drops a 1 or 0 but "the grey zone" with reference to jitter affects the transmission even if noting is actually dropped.
    I think you may have misunderstood the point he was trying to make when he mentioned the 50ft cable. What he was talking about was there there are both upstream and downstream information. It was just an extreme example to demonstrate its importance and how data can be corrupted.
    Finally, everyone seems to talk about a "properly constructed and shielded" USB cable and assumes that the one that came with their printer is one such specimen. Weird that.
    Wildcatsare1 likes this.
  8. x838nwy
    And you know this for a fact? Before jumping to such gravely conclusions, have you actually tried any other cable than the one you're using? Have you read the articles to which my links lead? If not, just read my post above.
    A little bit of background for you then; I have sent back a number of cables (RCA's, XLR's and Coax) costing hundreds of dollars and retaining my Blue Jeans Cable LC-1 as I do not hear the others doing anything to enhance my system. I am a big fan of both Schiit and BJC and totally love their no-nonsense attitude towards snake-oils and placebo's. I have huge respect for Jason and even have an e-mail from him telling me basically that all USB cable are the same. I've put together all my systems with Blue Jeans Cables speaker cables, 75 Ohm coaxes, interconnects and speaker cables. At the same time, I've tried many cables from big-name brands against what I have and sent many back. So, no, I'm not partial to expensive wires. Actually, if we look at my posts, I am mostly 
    I will admit that my method of basically just listening to the thing are not the most scientific (like a 2xblind or something), but I'd like to think that from all that I've tried, I'm not all that susceptible to the "wow look at the pretty cable" effect. Nor am I partial to trying to justify my purchases through my aural imagination. I am given to research and trying things out cos it's part of the fun. Okay, I actually own a Shakti Stone but that was a particularly painful experience - I missed the return window by a week due to an illness/travel delays - but I'd happily admit that it does basically nothing.
    It's all very easy to dismiss others views as placebo. I did too, in fact. But then reading a number of posts on a number of sites and a few articles got me interested so I did some investigation and now I own a few cables I like. It is unfortunate that there are a number of expensive USB and other cables that really do nothing different to what the one that came with my Canon does. It's also true that if I were to use the less sophisticated amps that I don't hear any difference at all. At the end of the day, cables don't rank high on the performance vs. $ list, and I'm sure there are $+1k cables out there that are just pure folly. But to dismiss it all as placebo is certainly a bit rich. If you don't think my opinions are valid, I'm happy with that. But please refrain from assuming more than you know about me or any effects I might be under.
    Anyway, let's get back on topic: I'd LOVE to hear from any member who's head the Modi + Vali combo!!!
  9. PanpandaChan

    I believe you too are misunderstanding his writing. "The grey zone" is referring to a signal with a voltage that falls right in between the max acceptable for a 0 and the min acceptable for a 1. So yes, nothing is dropped, the worst that happens is that a bit gets flipped when it shouldnt (which is what I was talking about...). Although I dont quite get what the guy is saying about the bit in the grey-zone being flipped at a later time... What flips it? I guess the DAC itself has to decide at that point what the bit is.
    But anyway, audiophiles seem to call the resulting effect: "jitter." I've never noticed any of this jitter myself and no one has ever shown me an intentionally bad source to demonstrate what jitter sounds like so I can't comment on how obvious a bad cable would be.
    Fair point about the USB audio transmissions and the lack of error checking. Asynchronous data transfers are indeed void of CRC checking.
    This is what allows a bit to be flipped without any correction.
    But calling a USB transmission analog bothers me...
    Yes, the signal is "analog" in the sense that it is voltage over a line. But what makes it digital is that the voltage follows certain conventions and is translated at the end point to whatever it is supposed to be (a sound in your ear, a color of a pixel, etc). With this logic, you could say the entire world is still analog, because yes, we still send everything by using power to transmit waves over some kind of medium. Yes, your wi-fi and bluetooth would even be considered analog at this point...
    So, (1) telling me the visualization of 1s and 0s being sent is not what "really is transmitted" is like telling a reviewer to be specific down to the Hz when talking about lows, mids and highs.
    (2) I can't quite comment on this since I've never heard the milliseconds of jitter in my music. But I thought you were talking about lows, highs, etc sounding better? Is that really what gets affected by timing? Because when I imagine jitter, I think about stuttering. Seriously. I have no idea.
    (3) I never said a bit gets dropped, I said a bit can be at worse erroneously flipped, which is what he said.
    He was talking about the transmission rate getting screwed up because the cable was too long. The PC sends out data and expects some sort of feedback based on speeds specified in a standard (I assume), and the DAC sends this feedback, but the length of the cable is far longer than acceptable. And I guess in that case, the difference in transmission speed was big enough that it caused issues.
    This I do believe because I've done it before.. Tried to use a USB extension cord to reach my old DSL modem across a room, my PC wouldnt even recognize it.
    Excessively long cables do screw up USB transmissions, this is a confirmed phenomenon.
    Why is it so hard to believe that someone created a proper cable that carries a signal? I think Hi-Fi guys worry more about USB cables than anyone else, kinda nuts.
    Dont forget that the digital signal travels through a bunch of other circuitry on the motherboard before even reaching the USB port that your cable is connected to.
    And even worse, if you're using the USB ports on anything but the back of the computer, then those ports are actually connected to the motherboard using a typical cable worth less than $2. Reasonable high-end motherboards cost around $200-300. The Modi costs $99. . . Cables cost more than this. Does it really make a difference when there are plenty of other weak links in the chain? Or are those links not weak at all...
    I'm not sure if theres any point in continuing this discussion. I dont think either of us will be swayed and we are just dragging the thread far off topic.
    This is also apparently, and not surprisingly, a topic that has been discussed to death before: http://www.head-fi.org/t/546191/usb-cable-supposedly-improving-dac-sound-quality-how-can-i-take-other-posts-seriously-after-that
  10. tdockweiler
    Can someone tell me why my USB laptop hard drive works with a 5" cable but not a 3 foot one?
    I always found this bizarre. LOL it's like the power stops halfway and says "Nope, not gonna happen" [​IMG]
    Basically my rule for USB audio is to use a cable that's not too long or over 6 foot.
    Oh and that USB ports are junk 9/10 times in my experience. Especially when it comes to laptops. My desktop is also custom built with good parts, not junk.
    I just switched to Optical output and am glad to not have to deal with USB anymore.
    I have no problems paying $30 for a better built USB cable. Never have yet. Maybe if it's made in the USA [​IMG] You know it's impossible to find one under $20 locally where I live. No joke.
    I do however use a Monoprice USB cable for my Modi.
  11. x838nwy
    For a "high" there's a level, let's say >=3V and for a "low" there's another level, say <=2V. In this example anything 2>x>3 V registers as the state previous to the cross-over. From what I understand, the DAC looks at the input at given instants and takes whatever level is there. So if the change is slower than it should be, then the DAC reads a value which is effectively "wrong", hence timing matters. The DAC only decides from what thresholds and this may be a source of error.
    I think the point here is that the waveform doesn't look like a bunch of vertical lines jointed by horizontal lines at the top/bottom.
    In my post, I did not specifically mention highs/lows in the normal sense - mainly other characteristics like boomy or bassy etc. I actually did mention that the data sent over usb doesn't correlate to specific frequency of sounds exactly. I cannot really say specifically what jitter sounds like, but on my PWD, the digital lense feature is said to reduce jitter and it certainly does sound more clean and umm.. more coherent to me when I switch it on.
    No it's not. It's just that we assume that the free cables are perfectly built and perfectly shielded and all that. People grab the one that comes with their printer and says it's perfect. USB cables fail quite often, just look at reviews for 'nomal' usb cables on Amazon. And hi-fi people worry about usb cables because our data transmission does not have the same problems as with external hard drives or printers (which has error correction but people's lives are ruined when they break/fail). We just use it differently to most other applications, that's all.
    Yup. And signals inside a CD player or amplifier or whatever went through resistors and capacitors costing cents each. The whole point of audio to me, is to preserve as much of the original track information as possible from the source right up to my ears without adding anything to said information. There are inevitable losses and we use whatever convenience and occasion allows. In the case of a computer, I agree with you that through all that electronics, things are not going to be as pristine as one might like but I prefer to work with what comes out without adding anything to it or degrading it further.
    There is very little point in continuing this further, I totally agree. There's enough BS on cables as it is. But if you ever have the opportunity, please try it out for yourself. Thanks.
  12. PanpandaChan
    It might really be that way lol. Hard drives usually take a decent amount of power to run, thats why some of them have special cables that have two plugs on the PC side, so it can take power from two ports. Not sure on your situation though.
    And yea I used one of the many USB cables I have in my drawer lol. They've accumulated over the years from different peripherals I bought.
    Its odd when I think about it... I have 4 or 5 of these USB-B cables and none of them came from printers I bought in the past =.= Always came from some other peripheral (like a modem or hard drive). Why are printer manufacturers so cheap ):
    EDIT: Damn ninja x838nwy lol.
    This has definitely been an interesting chat and I do see your points.
    Not sure if I'd ever give it a try myself. If I do, it would admittedly probably be with a moderately priced cable, which might not make enough of a difference to notice.
    Maybe I'll find a head-fi friend in real life with one of these crazy cables for me to try out lol.
  13. x838nwy

    From Wikipedia:

    USB 2.0 provides for a maximum cable length of 5 meters for devices running at Hi Speed (480 Mbit/s). The primary reason for this limit is the maximum allowed round-trip delay of about 1.5 μs. If USB host commands are unanswered by the USB device within the allowed time, the host considers the command lost. When adding USB device response time, delays from the maximum number of hubs added to the delays from connecting cables, the maximum acceptable delay per cable amounts to 26 ns.[52] The USB 2.0 specification requires that cable delay be less than 5.2 ns per meter (192 000 km/s, which is close to the maximum achievable transmission speed for standard copper wire).

    ^ so that's one limiting factor. You must also take into account that you're operating under less than ideal condition - the port maybe shared with other devices which draws more power than the port can actually supply. The cable itself may be attenuating the signal more than the norm also.

    How much does a pangea cable set you back?
  14. Barry S
    This thread has gone seriously off-topic. Can we please move the cable discussions somewhere else?
  15. x838nwy

    I'm entirely cool with that. Still waiting for Modi + Vali combo impressions....
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