[alekc]

Hi all,

I was having charging issues with my Mojo. I had it serviced (including the installation of a new battery) AND I got new USB cables directly from Chord. Here’s the thing: I have used a combination of THREE Apple 2A chargers with THREE different USB cables... nothing has changed the problem. I only get one hour of playtime from over eight hours of “charging”. The light doesn’t flash when charging, it remains on.

Any thoughts?

Andrew

While it is probably not the best advice possible as a quick test you can try to charge Mojo using your computer for a test.

 

[miketlse]

Hi all,

I was having charging issues with my Mojo. I had it serviced (including the installation of a new battery) AND I got new USB cables directly from Chord. Here’s the thing: I have used a combination of THREE Apple 2A chargers with THREE different USB cables... nothing has changed the problem. I only get one hour of playtime from over eight hours of “charging”. The light doesn’t flash when charging, it remains on.

Any thoughts?

Andrew

What was done during the servicing, apart from replace the battery?
Also was the servicing performed at a Chord recommended service centre?

 

[Andrew Montreal]

What was done during the servicing, apart from replace the battery?
Also was the servicing performed at a Chord recommended service centre?

Nothing that I know of. He did say something was loose... I imagine he tightened whatever it was. And yes, it was a Chord recommended service centre.

 

[Andrew Montreal]

While it is probably not the best advice possible as a quick test you can try to charge Mojo using your computer for a test.

Will try. Hadn’t thought of that. Thanks. Is there an ideal charger? The strange thing is that the Apple chargers worked for the first three years. And I didn’t use the unit much.

 

[surfgeorge]

Will try. Hadn’t thought of that. Thanks. Is there an ideal charger? The strange thing is that the Apple chargers worked for the first three years. And I didn’t use the unit much.

I would take it back to the service place and ask them to fix it.

 

[miketlse]

Nothing that I know of. He did say something was loose... I imagine he tightened whatever it was. And yes, it was a Chord recommended service centre.

Making the reasonable assumption that the new battery is fine, then replacing the battery has not cured the original issue.

Potentially the battery charging circuit is faulty (and the service centre didn't identify/correct this), or the battery could be very deeply discharged (see this info from the FAQ in post #3).

Mojo is taking much longer than expected, to charge
First, check that your charger is rated for at least 1amp charging current (higher is fine; lower is not). If the charger is not rated high-enough, then Mojos white charging LED will flash, to warn that Mojo will not charge successfully.

However, if your charger is fine, then it may be that Mojos battery has been discharged more-deeply than usual:

@Rob Watts said

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.
​

 

[Andrew Montreal]

Making the reasonable assumption that the new battery is fine, then replacing the battery has not cured the original issue.

Potentially the battery charging circuit is faulty (and the service centre didn't identify/correct this), or the battery could be very deeply discharged (see this info from the FAQ in post #3).

Mojo is taking much longer than expected, to charge
First, check that your charger is rated for at least 1amp charging current (higher is fine; lower is not). If the charger is not rated high-enough, then Mojos white charging LED will flash, to warn that Mojo will not charge successfully.

However, if your charger is fine, then it may be that Mojos battery has been discharged more-deeply than usual:

@Rob Watts said

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.

The chargers I use are 2A so we are fine there. Also the battery is new.

Here’s where it gets odd... the guy who repaired the unit was able to fully charge it. The unit came back to me fully charged. So it would appear to be okay. MAYBE I have THREE malfunctioning Apple 2A chargers? The thing is that they all fully function with the iPad and iPhones.

 

[miketlse]

The chargers I use are 2A so we are fine there. Also the battery is new.

Here’s where it gets odd... the guy who repaired the unit was able to fully charge it. The unit came back to me fully charged. So it would appear to be okay. MAYBE I have THREE malfunctioning Apple 2A chargers? The thing is that they all fully function with the iPad and iPhones.

In that case, if your battery was charging ok, but isn't now, then the next two potential root causes to exclude are:

• the battery having been deeply discharged, and needing recalibration (which i mentioned in my earlier post)
• are those Apple chargers 'smart chargers' ? Smart chargers can cause problems, because some have the tendency to switch off early, without warning the owner who innocently assumes their battery has been charging for 8 hours, but has only been charging for half an hour for example. So it would be worthwile you trying to charge but using a different charger.

https://www.head-fi.org/threads/chord-mojo-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/post-13019804

 

[surfgeorge]

I have recently started to use the Mojo with the 3,5mm Coax cable and recognized that there is a fairly quiet, high pitched noise coming from the IEMs.
When I switch on the Mojo it's dead quiet, until it's booted, then I hear a faint click and the noise starts. It may go away after a while (like switched off, not gradually).
It's like Tinnitus.

I tried to remove any source of RFI in the area but that has no influence.
It does not matter if the coax is connected or not. But if I connect USB it's immediately gone.

This has been described before:
https://www.head-fi.org/threads/chord-mojo-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/post-12007934

Any conclusions as to how this can be solved?

 

[miketlse]

I have recently started to use the Mojo with the 3,5mm Coax cable and recognized that there is a fairly quiet, high pitched noise coming from the IEMs.
When I switch on the Mojo it's dead quiet, until it's booted, then I hear a faint click and the noise starts. It may go away after a while (like switched off, not gradually).
It's like Tinnitus.

I tried to remove any source of RFI in the area but that has no influence.
It does not matter if the coax is connected or not. But if I connect USB it's immediately gone.

This has been described before:
https://www.head-fi.org/threads/chord-mojo-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/post-12007934

Any conclusions as to how this can be solved?

If the noise occurs when the Mojo is charging at the same time, it can be a noisy VBUS line, or the charging circuit changing to low power mode.

From the FAQ in post #3

Originally Posted by Rob Watts /img/forum/go_quote.gif

The noise is due to ripple voltage on the charger upsetting the inductors/capacitors within Mojo. If you use a clean quality PSU & a low resistance USB cable to the charger PSU the mechanical noise should be silent or insignificant.

Rob

Originally Posted by Rob Watts /img/forum/go_quote.gif

The problem is a noisy USB VBUS power line, & this makes the inductors in Mojo vibrate. Also, some USB cables have high resistance, & this makes the problem worse - so using a different cable can make the mechanical noise go away. The PSU itself can make it better or worse. Don't worry about it if you hear the noise, Mojo is not faulty & will continue to be reliable.

Rob

rob watts said:

jd007 said:
is it normal to have the mojo make a hissing sound (ie the unit itself, audio output is fine) when plugged in to power? brand new unit but it makes this weird noise when its plugged in (both when off and on). the hissing dies down when i plug in the signal cable (unit still off), not sure if i should send my unit back.
Click to expand...

It's normal - it is the charging regulator going into low power mode. Don't worry, there is nothing wrong.

Rob

 

[surfgeorge]

If the noise occurs when the Mojo is charging at the same time, it can be a noisy VBUS line, or the charging circuit changing to low power mode.

From the FAQ in post #3

Originally Posted by Rob Watts /img/forum/go_quote.gif

The noise is due to ripple voltage on the charger upsetting the inductors/capacitors within Mojo. If you use a clean quality PSU & a low resistance USB cable to the charger PSU the mechanical noise should be silent or insignificant.

Rob


Originally Posted by Rob Watts /img/forum/go_quote.gif

The problem is a noisy USB VBUS power line, & this makes the inductors in Mojo vibrate. Also, some USB cables have high resistance, & this makes the problem worse - so using a different cable can make the mechanical noise go away. The PSU itself can make it better or worse. Don't worry about it if you hear the noise, Mojo is not faulty & will continue to be reliable.

Rob

Thanks for the reply, but it is not the buzzing during charging. It is a high pitched fairly quiet background noise on the output.
I never charge and listen at the same time.
When I switch on the Mojo, it is dead quiet for a few seconds until it switches the output on, then there is this noise. Faint but audible and definitely disturbing. And if you use the USB digital in the noise vanishes as soon as the Mojo is connected to the source, but with coax it remains for a while and then suddenly goes away. But I have not observed it long enough to find a clear pattern.

 

[vlach]

Is anyone using the CA Vega iem with the Mojo? The Mojo is often described as warm, thick and slightly dark sounding which is pretty much the way i would describe the CA Vega.
Worried about resulting tonal balance and potentially bad synergy.

 

[Augustin1]

hello again!

I can't figure out how to use Winamp on laptop with Mojo, in Winamp settings it is present and activated, but Winamp crashes when i hit play. Dragonfly is working properly , Mojo is working on Tidal and everything else, except for Winamp.

 

[pumin]

I would still advise you to use Xduoo X10T II

hi alekc ... do you mind comparing which gives better SQ between these?

1. PC --> Asio Driver (Chord Mojo's driver) --> USB ---> Chord Mojo

2. Xduoo X10T II ---> SPDIF (Coaxial or optical) ---> Chord Mojo

 

[ZappaMan]

Right
I wanna use it as a portable setup
Also with usb
I have fiio otg micro usb to usb C

A second hand iPhone or iPod touch