1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.

    Dismiss Notice

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

Discussion in 'Portable Source Gear' started by Mython, Oct 14, 2015.
  1. doraymon
    I own both Hugo and Mojo and the only time I heard sibilance or harshness in the treble was with (and due to) the K3003i IEMs. No problem at all with SE846, Hifiman Edition X (V1 & V2), Meze 99 Classics.
    All of these I tested directly and consider myself very sensitive to sibilance and aggressive treble.
    I suspect it's your 600s, although I never heard they are bright.
     
  2. DJ The Rocket
    I read the FAQ in comment #3 and I was thinking about the ultra-precise timings Rob talked about often. And I have a question: should it be expected to sound noticeabley less distinct if the cable going to one ear is 12 inches longer than the other? Based on what he was saying, should that be enough to throw the Mojo off it's ideal timing and thus presentation?

    EDIT: If 12" isn't enough difference to make a noricable degradation of sound clarity, how much differential is?
     
    Mython likes this.
  3. Rob Watts
    A fixed delay of about 10 nS would be completely inaudible - and this is not where the problem lies.
     
    If you were to randomly adjust the timing (adding or not adding it), then the delay would become audible and measurable - it is because the delay (or timing) is constantly non-linearly changing that it has important consequences for sound quality.
     
    Now the levels of delay is much worse than this, simple interpolation filters have timing errors on transients of  around 100 uS - that's like randomly adding 2 miles of wire or not - and this then becomes highly audible.
     
    Rob
     
    Chord Electronics Stay updated on Chord Electronics at their sponsor page on Head-Fi.
     
    https://www.facebook.com/chordelectronics https://twitter.com/chordaudio http://www.chordelectronics.co.uk/
  4. miketlse
     
    I assume that if the OP randomly added 2 miles of wire or not into the cable to just one earpiece - the impact on impedance and frequency response for that earpiece would also be highly audible.
     
  5. Mython Contributor
     
     
    Anyone that random is beyond even Rob's skill to help! [​IMG] 
     
  6. jwbrent

    Aha, so this QR code on the Mojo is now normal. At least I know I have the latest version.
     
    @Rob Watts, is there a reason why Chord decided to add this, and what do the numbers beneath it represent?
     
  7. jwbrent
    I am ecstatically enjoying the sound of my new Mojo with my AK240SS as a transport. I find the tonal character is highly synergistic with my K712s.
     
    I had previously purchased a right angled 7cm OTG cable off eBay that works perfectly between my Mojo/240SS stack, but I can't help wondering whether the Audio Technica mentioned in this thread's FAQ would be better sounding. There's a 7cm version of the AT on eBay, but it sells for ~$70 and is not right angled.
     
    I may wait for other 7cm options that are right angled; it's a clean looking connection.
     
  8. GreenBow
     
    Hi thank you Rob for your patience.
     
    This conversation started in my post http://www.head-fi.org/t/784602/chord-mojo-dac-amp-faq-in-3rd-post/26310#post_13031709 
     
    Anyway with reference to your reply:
     
    Your paragraph one:
    You are suggesting that the charger is running at constant voltage of 8.2V under certain conditions. However they are 5V chargers. I thought I understood that you did some clever electronics and got the charging circuit within the Mojo up to 8.2V. I read that somewhere, but goodness knows where.
     
    Your paragraph two:
    You said of the battery. It won't charge or discharge, is held at a safe level, and will operate like this for a very long time. However mine would not remain constantly fully charged. It charges for a while and then the charging circuit switches off, and it runs from battery.
     
    Your paragraph two again:
    This is getting at what I was asking originally on page 1755. Where the Mojo gets power from when the battery starts off fully charged. Then while plugged in, discharges a little from use, causing the charger to re-engage. (I recall ages back you said the charger starts up once the battery level falls 0.2V.)
     
    You see I was asking from the point of view that the Mojo gets its power from the battery in most circumstances. Meaning it's used as a battery powered device. Thus negating PSU noise in the circuits, allowing for a better audio quality sound. ..However we that use the Mojo as a desktop device are in a different situation. Thinking about this was trying to work out what was happening. I was sure the Mojo was playing music from power supplied by the charger. Yet people keep butting in and saying the Mojo can only take power from the battery.
     
    Your  paragraph three:
    However you seem to be explaining here that the Mojo drawing power from the charger to play music is OK. Explaining that noise is negated from the charger because of the output impedance of the battery.
     
     
    Anyway thank you again. You see I asked ages ago if the Mojo could be run from a charger, with the battery removed. Someone gave me a blunt one word answer of no.
     
    Yet I have been wrangling with this for ages. This is the crux of what I am wondering. I am thinking in terms of using the Mojo as a desktop device only. Could I remove the battery and run it from a PSU only? I figured the Mojo had to be running off the charger for audio, when charging whilst playing. (Which I am sure you just said it does.)  
     
    If it were possible to run the Mojo from a PSU (and without a battery) there would be an issue. It would mean having to supply the Mojo with a very clean PSU. That's precisely what I have thinking. Please is that possible?
     
  9. corius
    The frequency response would depend on whether the wire was coiled or straight.
     
    I suggest you try it as an experiment and get back to the group with your findings. Or, even better, tell the Sony Z1/A1  and AK380 threads. That should keep them busy for a while!
     
  10. howdy
    I just bought mine and it has a sticker on the back but has the newer style box. I bought it from Amazon UK. Are there confirmed fakes out there?
     
  11. jwbrent
    Here's the picture I promised of the QR code/number on my new Mojo ...
     
    QRcode.jpg
     
    Mython likes this.
  12. GreenBow
     
    Definitely would not have expected that. You're going to have to see what Chord Electronics say. Thank you for posting.
     
  13. Mediahound
    ^ That looks quite strange indeed. You would think they would make the ink dark grey or something so it blends in better. 
     
  14. Mython Contributor
     
     
    It's not ink - it's laser-ablated.
     
     
     
    I admit I don't know the reason for the placement, however.
     
  15. Mediahound
    Maybe it's something new Chord is doing to prevent counterfeiting? Let's hope we can get some confirmation.  
     

Share This Page