Chord Mojo DAC-amp ☆★►FAQ in 3rd post!◄★☆
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Lycosa777

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I thought when you said noisy you meant the voltage on the VBUS.

What you are describing is something different.

I see.

In that case, if anyone could post a possible solution that would be great!

Mojo is brilliant, and so I hope to reduce the trickle charge noise as much as possible.
 
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earfonia

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  Bought an Anker charger (this) and used the included cable to check for noise.
Roughly 50% quieter than using an HTC charger, but still noisy. Same result using another cable I bought for about $8 US.
Anyone else have this experience?

Not sure if I just wasted money I could have used for more music...
 
Besides noise from charger, EMI could another source of noise. I did a simple test here:
 
 
If EMI is the issue, USB isolator might help to isolate the USB ground from the analog circuit. I found that Mojo USB ground is connected to the analog ground.
 

 
Compared to ifi micro iDSD Black-Label:
 
 
 
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Ra97oR

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I have a newer model of the mojo now.

With the new model there is now noise on trickle charge, where the old one was silent on the same setup.
 
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Lycosa777

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Besides noise from charger, EMI could another source of noise. I did a simple test here: (Removed for ease of quoting)
 
If EMI is the issue, USB isolator might help to isolate the USB ground from the analog circuit. I found that Mojo USB ground is connected to the analog

I too thought that EMI might be the problem so I moved both the charger and the Mojo from other electronics and used a cable with ferrite cores attached on both ends.
Still noisy. Been looking at the Schiit Wyrd but I have my doubts, whether it will work or not.

Tyvm for your post.
 
I have a newer model of the mojo now.

With the new model there is now noise on trickle charge, where the old one was silent on the same setup.

I wonder why that might be?
I assume you made your guide based on your previous Mojo, hence our results being different?
 
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traehekat

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Just ordered the Mojo, can't wait to receive it. I'm excited to finally have a truly portable hi-fi system. 
 
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theveterans

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I too thought that EMI might be the problem so I moved both the charger and the Mojo from other electronics and used a cable with ferrite cores attached on both ends.

Still noisy. Been looking at the Schiit Wyrd but I have my doubts, whether it will work or not.


Tyvm for your post.

 


I wonder why that might be?

I assume you made your guide based on your previous Mojo, hence our results being different?

Just avoid USB and use optical. Problem solved
 
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RobinTim

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Ra97oR

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Just avoid USB and use optical. Problem solved

If only it were that simple! Its more of a power related issue, not an audio problem.

I use optical exclusively on Mojo when it is at home. The "noise" is related to audible noise coming from the unit instead of "signal degrading noise" coming out of the 3.5mm jacks.
 
I am not sure what have changes on the new one, but the ripple charge (or when fully charged and used as a desktop DAC) is now audible when it is left on a desk at a reasonable distance.
 
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traehekat

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Thoughts on this new case? Pretty elegant solution if you are fine with pairing Mojo with the AK70.






Sent from my iPhone using Tapatalk
 
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Arpiben

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Besides noise from charger, EMI could another source of noise. I did a simple test here:




If EMI is the issue, USB isolator might help to isolate the USB ground from the analog circuit. I found that Mojo USB ground is connected to the analog ground.




Compared to ifi micro iDSD Black-Label:


 
Nice video and pictures.
Nevertheless it is also a bit confusing since:
1. Resistance measurements are done at USB shield level.(Not all cables are shielded at all or at both ends)
2. Noise measurements are done through different USB cable (with & without jumper)

That said, regarding Mojo, it is true that all In/Out grounds are common.
Rgds.
 
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idabgamgsx9754

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I use optical exclusively on Mojo when it is at home. The "noise" is related to audible noise coming from the unit instead of "signal degrading noise" coming out of the 3.5mm jacks.
 
I am not sure what have changes on the new one, but the ripple charge (or when fully charged and used as a desktop DAC) is now audible when it is left on a desk at a reasonable distance.
For the reason, I was thinking of getting a linear USB power supply to feed the mojo.  There wouldn't be any switching at all.  But that's only a guess as to the source of it.  
 
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jwbrent

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  Just ordered the Mojo, can't wait to receive it. I'm excited to finally have a truly portable hi-fi system. 

Congrats! Your music listening is about to become transformative. 
 
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@x RELIC x & anyone else who owns higher-end Chord DACs:
 
Could you go to 1:50 in this track and compare the impact of the drums for me?
 
(Mojo first, then the others. I guess you should use headphones that excel at impact too. Crank the volume so you can feel the impact and try volume-matching as well as you can. And feel free to enjoy the entire track. It's from this phenomenal movie.)
 
I noticed that cheap DAC/amps and the like hit a lot harder than the Mojo in this respect, although the Mojo has much better sound quality. I was hoping the DAVE, Hugo 2, etc. would also hit harder like that.
 
 
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