Chord Mojo DAC-amp ☆★►FAQ in 3rd post!◄★☆
Jan 22, 2016 at 1:59 PM Post #9,768 of 41,492

fluidz

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Mine was more like pink noise, now I have unplugged it and it works fine, but where was that noise from?


For approx two seconds when first plugged in there was a slurring coil whine coming from the unit, similar to that heard from a graphics card, quite loud too. Once the noise stopped there's now a faint high pitch sound but only audible if putting my ear near it - this is whilst the unit is in it's initial 10 hour charging before use period as recommended on the box.  

I've never heard such noise from my Ha-2 so came as quite a shock.  They should of written that on the back of the box if it's normal??

Sticker placement could do with revising lol




 
Jan 22, 2016 at 2:11 PM Post #9,769 of 41,492

Ra97oR

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Mine was more like pink noise, now I have unplugged it and it works fine, but where was that noise from?


For approx two seconds when first plugged in there was a slurring coil whine coming from the unit, similar to that heard from a graphics card, quite loud too. Once the noise stopped there's now a faint high pitch sound but only audible if putting my ear near it - this is whilst the unit it in it's initial 10 hour period as recommended on the box.  

I've never heard such noise from my Ha-2 so came as quite a shock.  They should of written that on the back of the box if it's normal??


Oh the noise issue, I have figured out a few combo that does not emit noise. I have also ordered a good quality desktop USB charger with low measured ripple and spike, along with a better USB cable. I will report back in detail when I write my review.

Combo 1: Sony or Samsung charger + Sony or Samsung USB cable + extension cord = Loud whine, and it goes on for a few seconds and off for a few before it whines again for a few seconds. (most likely due to voltage drop on the lower quality extension cable, making the charging circuit resetting)

Combo 2: Sony or Samsung charger + Sony or Samsung USB cable = Loud whine lasting the only the first few seconds, faint charging noise after that.

Combo 3: Apple 1A charger + Sony or Samsung USB cable = No initial whine, very faint charging noise

Will report back when the supposingly superior charger and USB cable arrives. :wink:
 
Jan 22, 2016 at 2:21 PM Post #9,770 of 41,492

Rob Watts

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The noise is due to ripple voltage on the charger upsetting the inductors/capacitors within Mojo. If you use a clean quality PSU and a low resistance USB cable to the charger PSU the mechanical noise should be silent or insignificant. 
 
Charging times - its 4 to 5 hours if the unit is off from flashing red to full charge. But if you are using it at the same time, it will take much longer (maybe 12 hours), as current is being drawn to feed Mojo and less to charge the battery. Check that the charging LED is not flashing, as this indicates a fault such as insufficient current from the PSU.
 
Rob
 
Jan 22, 2016 at 2:55 PM Post #9,772 of 41,492

Ike1985

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  The noise is due to ripple voltage on the charger upsetting the inductors/capacitors within Mojo. If you use a clean quality PSU and a low resistance USB cable to the charger PSU the mechanical noise should be silent or insignificant. 
 
Charging times - its 4 to 5 hours if the unit is off from flashing red to full charge. But if you are using it at the same time, it will take much longer (maybe 12 hours), as current is being drawn to feed Mojo and less to charge the battery. Check that the charging LED is not flashing, as this indicates a fault such as insufficient current from the PSU.
 
Rob

 
Won't mojo last for as long as you need it so long as it's plugged in-because the current supplied via charger is greater than the current being output? I'm sure this varies based on the power demands of the headphones/iems and charger used.
 
Even youtube recordings of intentionally bad quality black metal(it's a black metal thing) sound great on mojo.
 
Jan 22, 2016 at 3:06 PM Post #9,773 of 41,492

Ike1985

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If I had a phone with a removable battery it would be the perfect companion to mojo, because my Iphone 5 dies about 1/2 way through the day if I'm streaming albums via and lasts ~3/4 of the day if I'm just playing via onkyo HF.  I hope the Samsung S7 has a removable battery and microSD, that would be perfect: big capacity and when the battery gets low just swap it for the full one.
 
Jan 22, 2016 at 3:51 PM Post #9,776 of 41,492

Ike1985

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I don't know if this is possible but it would be cool if there was a lightning port splinter, male into the phone that terminates into two females. Allowing me to charge iPhone 5 and send data to mojo at the same time.
 
Jan 22, 2016 at 4:15 PM Post #9,777 of 41,492

Beolab

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Won't mojo last for as long as you need it so long as it's plugged in-because the current supplied via charger is greater than the current being output? I'm sure this varies based on the power demands of the headphones/iems and charger used.

Even youtube recordings of intentionally bad quality black metal(it's a black metal thing) sound great on mojo.


Can you recomend a good charger with low ripple, because i just connected it with a Iphone travel charger A1400 5v / 1A
plus a 1,8meter USB micro 28 AWG x 2C no name cable.

This combo do most likely got high ripple effect.

I found a VANSON varible 6w charger 1A @ 6 volts with a low ripple according to spec be something to buy?
 
Jan 22, 2016 at 4:16 PM Post #9,778 of 41,492

GreenBow

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Got myself a Mojo two days ago, especially after owning a 2 Qute since its release.

Only using some Beyerdynamic DT770 Pro's 250ohm ATM with and iPhone 6 so that'll have to change soon.

 
There's a coincidence. I was just googling the Beyer DT 770 Pro, because I saw a singer wearing them. I was auditioning the Katie Melua Collection CD on youtube, and she's wearing them in one vid. It's, 'I will be there for You - Full Concert Version'. Gorgeous piece. (I think that track is not actually on the album, but just uploaded by someone inserted into the album.)
 
Sorry off topic I know but couldn't resist the coincidence.
 

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