[sanjeewasam]

Hear is my impression
 
Chord Mojo is a real winner and the best money I have ever spent on DAC/AMP. For AKG K812 I can confirm that it is the best I have heard of with Fiio E17k, Burson conductor, Luxman P-200, Vio 281/ Vio 850
 
I belive Mojo direcltly for K812 does better than Mojo as a DAC with other amps including Luxman ($1500) and Vio 281 ($2000)
 
With Mojo with HD800 sometimes show harshness and thin sounding but nevertheless quite good and for well recorded very good with good sound stage
 
Mojo is not however powerful enough for AKG K712 and Audeze LCD 2/w in my experience and should be paired with a better but Mojo could be used as a DAC

 

[jadeboy]

Quote:

 
*********************
Try charging overnight with the unit off. The charging circuit looks at the state of the battery before charging. If the battery has a very low voltage, it will trickle charge the battery until it gets to a safe voltage, and then full charge will commence. This trickle charge mode can take several hours, and it is done for safety reasons, and it will appear that the battery is not working as the trickle charge mode takes some time. When in this mode Mojo must be off.

When charging make sure the battery light is white and not flashing - if it flashes, pull out the charging cable, count to ten, re-attach the charging cable. If it continues to flash, it is most likely the charger is not giving 1A at 5V, so use a better charger.

Rob 

Unplugging the charger if it blinks and waiting then charging it again.. works.. but after a while the problem comes back.. I have similar setup in which I leave the mojo constantly on and chargering as a lineout DAC.

I don't think this is a charger/power bar/cable problems. I have used about 5 difference chargers with 1amp or more.. 7+ usb cables.. and 2 different power strips.

This could be circuit logic charging problem.

 

[Mython]

This could be circuit logic charging problem.

 
 
Mojo has over-voltage protection, but I suppose it may not be absolutely impossible to cause harm, if a 'turbo' mode USB charger is used, that may have flakey sensing/communication firmware (necessary to determine whether or not it is safe to use 'Turbo' high-voltage charging mode), particularly if plugged-into Mojo on a regular or continuous basis. Even with a well-implemented charging chip, incorporating over-voltage protection, there is only just so much abuse a protection circuit can withstand before eventually failing, if a charger is failing to ensure it definitely does not exceed 5V with devices, such as Mojo, that require no more than 5V charging supply.
 
In spite of people being repeatedly recommended to use simple 'dumb' fixed 5V chargers, some people seem absolutely determined to use fancy 'Turbo' chargers that, given an opportunity, may try to send higher than 5V through the microUSB port.
 
Although Hugo does not employ USB charging, I recall Rob saying something related, in relation to Hugo:
 

 

   
Thanks Rob.
The first time I had my TeddyPSU connected and OFF. My thought was that the Hugo indeed discharged in the PSU.
 
I tried with the PSU disconnected and the battery depleted in a day all the same.
 
This could explain why it took literally 3 hours to have the first sign of operation from the unit when I received it (I thought the battery or the charger was dead. I was expecting it to come alive after ~30mn). 

Chord have had a couple of failures of the over voltage protection, which is used to protect the charger. This has been because people have not been using the supplied charger, and using PSU units with too high a voltage, which then damages the protection circuits. The protection is there for transient events, not constant over voltage. 
 
It sounds to me that the protect circuit has been damaged, so you will need to send it back to your dealer for repair. Do not use other PSU's apart from the supplied charger - there is no benefit in sound quality with using other chargers, and there is a risk of damaging Hugo in using other PSU's.
 
Rob

 
 
 
Rob did remark, specifically in relation to Mojo:
 

 

  ...USB chargers exceeding the 5V standard - in that instance, I suppose the charger could (depending on how well Mojos charging circuit is protected) potentially 'force' charging at an undesired rate.
 
However, knowing how fastidious Rob, John and Matt are in their circuit designs, I suspect they would take the precaution of including over-voltage protection on Mojos charging input.

Yes there is over voltage protection on the charging port. This is intended for initial protection upon connection to avoid inductive over voltage surges damaging Mojo. The USB input must be a USB legal 5v input; the over voltage chargers have a communications protocol to set the voltage higher than the usual 5v; Mojo does not have this protocol, so a USB charger should not be able to deliver more than 5v.
 
Rob

 
 
 
Although I am only speculating about the above possibility, it would certainly be interesting to know, @ jadeboy & @ citraian, if you have been using chargers capable of exceeding 5v output, when charging Mojo,

 

[xtr4]

To add on as I've experienced this last year when I got my Mojo, certain newer quick charge type chargers also have an internal circuitry that provides high current up till 90 or 95% of the charge and trickle charge towards the end. This circuitry could be the cause of the Mojo not being kept topped up.

 

[Mython]

To add on as I've experienced this last year when I got my Mojo, certain newer quick charge type chargers also have an internal circuitry that provides high current up till 90 or 95% of the charge and trickle charge towards the end. This circuitry could be the cause of the Mojo not being kept topped up.

 
 
 
Yes, there are quite a few different scenarios that can influence successful charging, even when no damage has occurred, and your above scenario was discussed a few months ago, and makes sense when combined with what Rob said about Mojo:
 
 

 

  Hi Rob, and John,
 
I followed your exact instructions and the lights behave properly and I am now into my 6th consecutive album. When I now power off the Mojo completely, the battery white light, which was white throughout the listening session, now goes off, so it was definitely in trickle charge mode. I guess my Mojo wasn't fully charged when I had that problem earlier, or maybe it was a yellow light and these old eyes of mine cannot be trusted. I apologize for any confusion caused.
 
I now have 3 questions, if I may:
1. If I leave the Mojo plugged in to the wall wart all the time, that should be fine, correct?
2. I presume that any time I want to resume listening in its present setup (meaning listening via the computer and with the charging cable still connected to the wall wart), the Mojo should be "ready to go" and that there is no need for me to ascertain the battery level? 
3. If I then use the Mojo as a portable, and later on connect it back to the computer for listening (with the charging cable then connected to the wall wart again), what would be the minimum color of the battery light? Green?
 
Thanks once again.
 
George

John answered 1 and 2 fine, but I thought I would clarify exactly what happens when you charge and listen at the same time.
 
I use a dedicated charging chip for the Li battery, and this has a number of safety features, and works with a number of settings to ensure safety.
 
Now one of the safety circuits is a safety timer, and this is when the charger is in full charge mode. This timer is set to about 8 hours, and normally full charge mode takes 4 hours, when the unit is off. But when the unit is on and playing, there is a risk that the safety timer will be set, as it can take 12 hours to fully charge (from flashing red) and when playing music (for those 12 hours) at the same time. If the safety timer is set, then the battery LED will slowly flash white, and no further charging will take place. To reset the timer, just disconnect the charge USB, wait 10 seconds, and reconnect, and it will recommence charging. So if you are charging and playing, then when you have finished listening, turn Mojo off, and it will be OK. When Mojo is blue, and you connect the charger, then it is trickle charge mode, and the safety charger is not operating. So if Mojo is green, the safety timer won't trip out, as it will play and leave full charge mode within 8 hours, so you will be OK. It should be OK at yellow too. I guess the easiest way of dealing with it is to turn Mojo off after listening, then you will be fine, unless you listen for longer than 8 hours starting from fully flat.
 
Note that you can get the flashing battery LED if the USB charger voltage is low, from a charger that can't supply the current, or a USB cable that has high resistance. But you will see this pretty early on.
 
I hope this clarifies.
 
Rob

 
 

 

  Thanks for the response. I am trying that short cable now that came with the Chord and it seems to be doing the same thing. I will let it sit for a bit, but I am thinking the battery is not holding any charge. 

Try charging overnight with the unit off. The charging circuit looks at the state of the battery before charging. If the battery has a very low voltage, it will trickle charge the battery until it gets to a safe voltage, and then full charge will commence. This trickle charge mode can take several hours, and it is done for safety reasons, and it will appear that the battery is not working as the trickle charge mode takes some time. When in this mode Mojo must be off.
 
When charging make sure the battery light is white and not flashing - if it flashes, pull out the charging cable, count to ten, re-attach the charging cable. If it continues to flash, it is most likely the charger is not giving 1A at 5V, so use a better charger.
 
Rob 

 

[Mython]

Also, @ citraian,
 
Your earlier posts seem a little ambiguous.
 
You said you turned Mojo off, and you also said there did not appear to be any thermal concerns, but, regardless of that, have you tried FULLY charging Mojo without interfering with it whilst it is switched-off?
 
(@ Arpiben mentioned this, too)
 
.

 

[Mython]

I need to get some sleep now, but, one way or another, we will try to resolve this issue, in due course!

 

[music4mhell]

To add on as I've experienced this last year when I got my Mojo, certain newer quick charge type chargers also have an internal circuitry that provides high current up till 90 or 95% of the charge and trickle charge towards the end. This circuitry could be the cause of the Mojo not being kept topped up.

What's the specifications of the charger which you are using in V/Amp ?

 

[Deftone]

Mojo is not however powerful enough for AKG K712 and Audeze LCD 2/w in my experience and should be paired with a better but Mojo could be used as a DAC

It is you just dont like the pairing

 

[xtr4]

What's the specifications of the charger which you are using in V/Amp ?

Samsung USB 3.0 quick charger for Note 3 @ 5V/2A has this issue.
LG G3 standard charger @ 5V/1.8A didn't have this issue.

 

[music4mhell]

 

What's the specifications of the charger which you are using in V/Amp ?

Samsung USB 3.0 quick charger for Note 3 @ 5V/2A has this issue.
LG G3 standard charger @ 5V/1.8A didn't have this issue.

If i am not wrong, Samsung one is not only 5V/2A.. it must have 2 output, one is 5V/2A and nother 9V/2A around ... let me google if i get any pic .!!

 

[xtr4]

Its the old Note 3 charger for their USB 3.0 socket which they only implemented once due to the stupid nature of the microUSB connector.

Edit: I've used this charger to charge my iPad mini and LG G3 as well and the overall charge time to 100% is slower than their respective original chargers

 

[sanjeewasam]

It is you just dont like the pairing

It is not that i like pairing. You notice that k712 and lcd2 does not sound right -base gone and no sparkels compared to running with burson. Not smooth. Definitely itbis not because of the mojo dac and to do with power required to drive these.

 

[jmills8]

I bought a headphone and I can easily tell the Mojo does better with it by adding a seperate amp. My experience with the moho with various iems are excellent but headphones the mojo lacks punch.

 

[AnnaMatronic]

I bought a headphone and I can easily tell the Mojo does better with it by adding a seperate amp. My experience with the moho with various iems are excellent but headphones the mojo lacks punch.

Since the main priority of a portable device like the Mojo should be performing well with IEMs, I am completely okay with this.