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Chord Mojo DAC-amp ☆★►FAQ in 3rd post!◄★☆

Discussion in 'Portable Source Gear' started by Mython, Oct 14, 2015.
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  1. headwhacker
    While USB and COAX are prone to noise  compared to Optical, the signal transmitted between a USB device and Mojo is still digital. A series of 1s and 0s when interpreted by the device before it is sent to Mojo must be the exact data when it is received by Mojo. Of course it's not 100% correct all the time that is why things like error correction exist.
    With the technology inside Hugo I doubt these errors are relevant. I believe, the problem comparing optical and USB inputs of Mojo is that the devices are different. USB devices are usually Android/IOS device which may interrupt with the music player app and manifest as a series of clicks and pops.
    However, difference reported in soundstage, details or bass would require IMO a shift in the interpreted analog signal which is highly unlikely because Mojo must interpret the same digital data to the exact analog signal all the time.
    I don't know any device/transport that has all 3 digital outputs but sources being used to compare the 3 digital inputs of Mojo are also different. It's possible the difference is due to the transport used and not the inputs in Mojo.
    shigzeo and Angular Mo like this.
  2. shigzeo Contributor

    I need to update the 'review'. The RMAA article was done with a hissy Mojo. The one I eventually purchased doesn't hiss much at all. 
  3. Currawong Contributor

    I'd speculate that in a similar way to how people can mis-interpret brightness as detail, the same might be happening on the effects of the noise on the eventual analog output. I don't think it has anything to do with error correction, but you might be right about the transport.  Once the new year is in, maybe Rob can post his input on the matter. It was discussed somewhat in the Hugo threads. [​IMG]
    Ideally we should just plug in whatever and not care too much about this, but like I said in the Vali 2 thread about tube rolling it, it's just one of those things that are part of the hobby for us regulars and something we play around with and discuss for fun. 
    simonm likes this.
  4. Mython Contributor
    'Sparkling' treble does not necessarily mean there is more detail being portrayed - it may actually relate to digital noise, so, when a DAC arrives on the market, that offers noise levels drastically lower than existing designs, there is a possibility that the treble may be perceived by some people as sounding a bit 'smooth'.
    The following post, from the DAVE DAC thread, is interesting (see point # 1.):
    [updated later contribution from Rob]:
    And although mostly relevant to the DAVE DAC, some of the following holds true (to a lesser, but still significant, degree) for Mojo and Hugo:
  5. Jawed
    Rob has a preference for optical on Hugo, but USB on Hugo TT. The difference between them is that TT has galvanic isolation.

    Mojo and Hugo don't use galvanic isolation as this would suck power out of the mobile device that they are connected to. You would drain the battery in your phone more rapidly if it had galvanic isolation.

    TT, being for home use, doesn't care if it drains power from the device that's connected to its "USB HD" input.

    The "USB SD" input on TT doesn't have galvanic isolation and is there for phones. It also works on Windows PCs that do not have the Chord driver installed.
  6. joshk4

    I agree.
    I do find it ironic, that people who dissect other people and then lay their own claims that a 1 db increase is a "big" difference somewhat puzzles me (I do find it a bit inconsistent - is this not an opinion/claim as well?).
    I wonder to what length do these guys go through to make sure all variables are not factors (not sure if this is possible). i.e a/b testing, switch box, testing against pink noise (if they want to go to the extreme considering how important variables must be considered). In the end, I'm sure not all variables are considered, and so who has the right to make opinions?
    After all, the Chord Mojo was a product to allow the general public to enjoy great sound. Should Chord put a note for each buyer, to tell them you must have volumn matching, must have a switch box before you can justify your own opinion on whether the sound has improve compared to your mobile/laptop.
    imattersuk and masterpfa like this.
  7. shigzeo Contributor

    Did I say 'big'? No, I said it was enough to elicit a repsonse. You are mis-representing what I said. Of course one cannot eliminate all 'variables', but before making bold claims such as the difference between cables or input methods, the least you can do is make sure the volumes are matched. And yes, because even small decibel differences can _elicit_ responses. As to the final argument: re: Chord taking responsibility for people's use of Mojo, of course not. That is silly. Of course you should decide what you like and what you dislike. But that never was the issue. The issue is making bold claims that have no practical method of falsifying. 
    I can say headphone A has more bass than headphone B and that bassheads should buy it. According to the logic you used to refute me (again, which you attacked with a straw man), that's the end of story. There is no reason to make sure that a statement conforms to truth. When you can't factually verify a statement, it is best to put in a disclaimer. An 'I think', a 'perhaps', or an 'appears'. But that is what we do in most of life. We try to be as honest as possible, and where we are not, be ready to accept correction, or add provisos to our statements. 

    Why is it that in Audio we can say whatever we want without the slightest attempt to conform to the rules etiquette or honesty? 

  8. joshk4
    I never said you did :)
    spook76 likes this.
  9. Mimouille
    I completely concur with Shigzeo. When I was newer to this game, I took many comments at face value and was ill advised into certain purchases.

    When I bought the Hugo, many claimed this source was clearly superior to that one, and when experiencing it myself, it made not a single difference to me. So for the Mojo, I will just trust my own ears.
  10. joshk4
    I too agree with him about it being peoples opinions.
    But for people to write that it is their opinion every comment, is superfluous.
    I'm not sure if audio gears are an exception to believing everyone's comment as definitive truth. If you do, than I'm not sure what to say really.
    Like you, trust your own ears is the best judgment. It is your ears after all.
  11. headwhacker
    I would not compare Mojo's input to Vali's tube rolling. First, they don't don't operate on the same domain. Second the input noise in Vali will have a larger impact on it's output as it is purely in analog domain. The noise in any of Mojo's input would have to be strong to flip a 1 to 0 or vice versa.
  12. headwhacker
    1dB difference is perceivable to almost everyone - claim.
    Hugo's soundstage is bigger, wider than mojo - opinion
    Got the difference?
    Nobody is asking you not to trust your ears. But if you know beforehand that the louder sounding amp will give it an advantage. Will you still going to rely only with your ears?
  13. Currawong Contributor
    I'm sorry, I think you misunderstood what I was getting at. It was nothing to do with comparing tubes to inputs, but comparing how those of us much into the hobby fuss over small details to a degree that is arguably excessive. [​IMG]
    In the Vali thread some members were wondering if they purchased the Vali whether or not they'd have to purchase tubes costing half the value of the amp. Similarly we have had members asking whether or not they need to worry about special cables, software, DAPs and DSD files to get the most out of the Mojo, when none are necessary. In both cases it is just a bunch of us experimenting with things to see what effect they have -- most of them very minor. [​IMG]
    simonm likes this.
  14. headwhacker
    Ah, apologies. It's easy for me to jump the gun on this one and took what you said at face value as I am not a frequent visitor of the Vali thread.[​IMG] 
  15. spook76

    You need to look up the words "claim" and "opinion" they are almost synonyms. A claim is an assertion in the face of possible contradiction while an opinion implies a conclusion while thought out yet open to dispute.

    Got the similarities?
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