Chord Mojo making noise when almost fully charged
Aug 21, 2017 at 8:41 AM Thread Starter Post #1 of 7

J053FK

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Long time reader, first time poster here!

So I bought a Chord Mojo of Amazon (UK) last week, and I'm really impressed with the way it's driving my HD650s. The only issue I have is that just before it's finished charging it starts making a hissing/high pitched buzzing noise. I've read that changing charger/cables can make a difference, so I've used an Apple charger, a Samsung charger, a Sony charger and both USB 2.0 and 3.1 connections to charge with a variety of USB cables and the noise still remains.

I should say that within a minute or two of the hissing/buzzing starting the white light turns off (IE charting finished) and the unit gives me 8-10hrs of playback after unplugging. I also don't get any charging noise throughout the rest of the charging cycle...only during the last couple of minutes when the charging is almost complete.

Do any of you have experience with the Chord Mojo? Can you comment on why the noise is happening and what I can do to prevent it? And most importantly - should I return my Mojo and have it replaced, or will I end up with the same issues if I get a replacement unit?

Thanks in advance for your help.
 
Aug 21, 2017 at 12:59 PM Post #4 of 7

Music Alchemist

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If this is for home use, I recommend keeping a 5V 2A wall charger permanently connected to the Mojo, charging it to full before turning it on and starting playback for the first time.

If you need a portable solution, you'll have to find it in the Mojo thread.
 
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Dec 16, 2017 at 1:00 PM Post #5 of 7

RiseFall123

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Long time reader, first time poster here!

So I bought a Chord Mojo of Amazon (UK) last week, and I'm really impressed with the way it's driving my HD650s. The only issue I have is that just before it's finished charging it starts making a hissing/high pitched buzzing noise. I've read that changing charger/cables can make a difference, so I've used an Apple charger, a Samsung charger, a Sony charger and both USB 2.0 and 3.1 connections to charge with a variety of USB cables and the noise still remains.

I should say that within a minute or two of the hissing/buzzing starting the white light turns off (IE charting finished) and the unit gives me 8-10hrs of playback after unplugging. I also don't get any charging noise throughout the rest of the charging cycle...only during the last couple of minutes when the charging is almost complete.

Do any of you have experience with the Chord Mojo? Can you comment on why the noise is happening and what I can do to prevent it? And most importantly - should I return my Mojo and have it replaced, or will I end up with the same issues if I get a replacement unit?

Thanks in advance for your help.

Exactly what happen to me with my brand new Mojo.

But I counted SIX MINUTES hissing, not three as you.

Apple 2V charger here.

What did you do after?
 
Dec 19, 2017 at 3:50 PM Post #6 of 7

J053FK

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My correspondence with Chord customer services is set out below. The short version is that the hissing noise is normal when using lower powered chargers. I’ve just continued to use the same charger and if the hissing is annoying me when using the unit I just unplug and recharge when I’m done.

Anyway – emails below. Hope this helps :)

Hi,

I purchased a Chord Mojo last week and I'm really pleased with the product. I do, however, have an issue with the unit…Towards the end of a charging cycle (just before the white light turns off) the unit starts to make a high pitched humming sound. The noise persists for a few minutes before the unit stops charging (i.e. the white light turns off), and if I unplug then re-plug the charger in again the noise repeats, and the white light turns off again. When I run the unit following charging the light indicates that the battery is fully charged, and I do not hear this noise throughout the rest of the charging cycle. I've tried with several different USB cables, and several different chargers - including an apple charger, a Samsung charger and from both a USB 2.0 and USB 3.1 header from my PC. Would you be able to give some guidance on whether I need to return the unit? Is the unit faulty? The noise is quite audible but only happens for a couple of minutes right at the end of the charging cycle.

I purchased through Amazon so can return the unit for replacement easily - please advise.

Thanks in advance for your help.

Kind regards,

Jon


Hi Jon


It is normal for Mojo whistle when on charge. The noise occurs when a lower quality charger is used. It is actually the filters within Mojo cleaning up the 5V on the USB input due to the voltage ripple. This means that it can be louder when in trickle charge mode too, as the charger is not under it's full load.


What you are hearing towards the end of the cycle is the noise of the trickle charge, so it is nothing to worry about.
 
Dec 19, 2017 at 4:59 PM Post #7 of 7

RiseFall123

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Thank you, same answer to me too.
 

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