[doraymon]

I have listened now to Hugo, 2Qute and Mojo with Senn HD600. Hugo was the best in terms of snap and resolution but got glare in highs I couldn't stand. Same goes now with the other two. Bought Mojo since it was told to be a bit more dark but still the same glare and hiss, especially with female voice s and f. I'm using laptop and USB connection with Audioquest Jitterbug (also tried without). Tested also with Gustard U12 USB to optical converter and with that bass goes away but glare stays.

Since Chord DACs should be great according to all reviews there must be something wrong with my setup. Or maybe I'm too sensitive to highs? Any ideas what to try? There isn't any glare problems with some other DACS I've tested recently, but otherwise they haven't been on par with Hugo/Mojo.

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.

 

[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?

 

[Rob Watts]

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?

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

 

[miketlse]

....that's like randomly adding 2 miles of wire or not - and this then becomes highly audible.
 
Rob

 
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.

 

[Mython]

 

....that's like randomly adding 2 miles of wire or not - and this then becomes highly audible.
 
Rob

 
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.

 
 
Anyone that random is beyond even Rob's skill to help!

 

 

[jwbrent]

Depends how quickly the retailers are rotating stock. The last batch that arrived with us has completely different packaging and a qr code lasered on one end of the mojo.

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?

 

[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.

 

[GreenBow]

 

  Yes of course @Mython. However it doesn't describe what state the Mojo is in does it? Playing, off, on but not playing.
 
He is talking about when there is no net charge on the battery. I am talking about when the battery level has dropped and when it needs a bit of charge. (While charging and playing, from a full battery.)
 
To be honest though I have probably over looked a simple principle of electronics and should know better.

To understand it better, let's assume Mojo is off and charging.
 
Now the charger has two modes of normal operation - constant current, which is set to 330 mA, and constant voltage which is set to 8.200 V. Now when the non charging battery battery voltage is less than 8.200 V, then the charger supplies a constant current. But when the non charging battery voltage gets close to 8.200 V, then the charger switches mode to constant voltage at 8.200 V. The current that is charging the battery then slowly falls from the initial 330mA, to zero - its in the trickle charge mode now. Eventually, the non charging battery voltage hits exactly 8.200 V, the charger is in constant voltage mode of 8.200 V, no current now flows into the battery, and the charger switches off automatically. When the battery voltage falls to 8.0 volts, then the charger will return to charging. Tip - if you want to force the charger to top up Mojo's battery to 8.200 V then removing the charge USB, wait 5 seconds, reattach, and the charger will top it up to 8.200 V.
 
Now imagine that Mojo is on at the same time as it is charging. In this case, the battery will continue to charge until it gets to 8.200 V, and the charger is set to voltage mode and gives 8.200 V too; so no current flows into or out of the battery; but Mojo itself is drawing 180 mA of DC current, and this will simply come from the charger - so the charger will supply the needed 180 mA for Mojo. It will do this for ever, and it won't switch off. This is intended, as it means that the battery is effectively not being used to supply the bulk of the current, won't charge or discharge, is held at a safe level, and will operate like this for a very long time.
 
Now we have been talking about DC currents, and this is indeed the vast bulk of the current. But what about dynamic currents and noise? Because the output impedance of the battery is much lower than the charger, then the noise of the charger is reduced; also dynamic currents still comes from the battery. So running in this mode ensures the best of both worlds - low RF and audio band noise from the battery, large dynamic currents available, and low PSU impedance too - but without the worry of the battery wearing out from charge and discharge cycles.
 
I hope this clarifies.
 
Rob 

 
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?

 

[corius]

   
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.

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!

 

[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?

 

[jwbrent]

Here's the picture I promised of the QR code/number on my new Mojo ...
 

 

[GreenBow]

  Here's the picture I promised of the QR code/number on my new Mojo ...
 

 
Definitely would not have expected that. You're going to have to see what Chord Electronics say. Thank you for posting.

 

[Mediahound]

^ That looks quite strange indeed. You would think they would make the ink dark grey or something so it blends in better. 

 

[Mython]

  ^ That looks quite strange indeed. You would think they would make the ink dark grey or something so it blends in better. 

 
 
It's not ink - it's laser-ablated.
 
 
 
I admit I don't know the reason for the placement, however.

 

[Mediahound]

Maybe it's something new Chord is doing to prevent counterfeiting? Let's hope we can get some confirmation.