[RiseFall123]

my serial number begins with M0552xx.

Thank you, mine is M056xxx, even newer than yours, with this whine on the end of charging while you don't have it at all. I little envy you.

I wonder if you are referring to reports of a loud hiss / noise that could be heard through the headphones (not just very low impedance headphones) that was in some early units. I had a tour unit that suffered from that anomaly and it was fixed for the rest of the tour. That issue was identified and fixed, but a few got out in the wild. I don’t think I’ve ever read that John said the charging coil whine was changed (and I’ve read every post of this thread from the beginning). There has been some confusion between these two different hissing/noise/whining sounds before.

With my unit (new and with a new serial number) I can say that:

- I have NOT any hiss on the headphone in every circumstances

- I have NOT any whine during the charging (even with my ear close to it), expept for the last 6 minutes

- I HAVE a whine (loud whine) in the last 6 minutes of charging, tried multiple chargers and two different cables.

Could be, I'm too lazy to go find it, bottom line is the end-of-cycle charging whine lasts about 10 minutes for me and it has zero to do with USB cords or chargers because I have many very high quality ones with intelligent voltage regulation, filtering, etc and the charging whine is instant no matter which cords, charger, outlet combination is used. Hey, maybe it's "normal" but it's weird and annoying, especially if some units have it and some don't.

Exactly my case.

It sounds like this: weeeeeeeeEEEEEEEEEEEEEEEEEEEEE[10minutes]EEEEEEEEEEEEEEEEEEEEEEEeeeeeeeeeeeeeerrrrrrrreeeeeee

Exactly, it's loud, louder than one can think.

The kind Rob assured me that is normal on some units and it's not damaging at all, now I have to struggle with myself If I want to give it back to the seller hoping on a replace that doesn't make the whine, sending back to Chord directly or keep my Mojo with this "issue".
I think that after the very kind Rob explanations I will keep it, but knowing that some unit is immune to this issue is not a great thing to me.

 

[SilverEars]

It's a loud whine with a tinny jet-engine kind of sound that's loud enough to hear on a separate floor of your house if other things are quiet, and it's coming from the Mojo itself, not speakers (course there's the EMI issue, that's another issue)

It sounds like this: weeeeeeeeEEEEEEEEEEEEEEEEEEEEE[10minutes]EEEEEEEEEEEEEEEEEEEEEEEeeeeeeeeeeeeeerrrrrrrreeeeeee over the course of last 10 minutes of the charging cycle.

That's how I first heard it - was getting ready for bed on the 2nd level of a house and heard this low volume whine ... I thought it might be a water pipe issue or something outside. I started searching all over the house and eventually discovered it was the Mojo and it was sitting all by itself on a desk in an office with the only connection being the USB charging cable. It was quite loud and noticeable in that room. I was super surprised because it's such a small device with no speaker but that thing is LOUD. Course I freaked out thinking it was going to start a fire (cause as we all know it gets pretty hot) and the next day did a bunch of research and found out it was "normal".

After a bunch of experimenting I could repeat the whine every time - again, just the Mojo and a charging cable.

Sounds extreme. Besides usb hiss due to dirty connection, have not heard such myself.

 

[SilverEars]

I have the mojo and love its sound. The only thing I wish it had is a bass boost. Chord really needs to come out with an app to use with the mojo and Poly with an eq.

Try Equilizer APO. Look into the Sound science forum, there is a thread about that.

It's interesting how bass isn't all that significant out of my Andromeda. You'd expect for such low OI. My 2ohm OI Opus #2 outputs greater bass.

 

[RiseFall123]

Sounds extreme. Besides usb hiss due to dirty connection, have not heard such myself.

He is not exagerating, my gf (who usually totally ignore this technical stuff at all) the other day shout at me that something wrong was coming from my Mojo under charge, the whine was not low, and she was worried like the unit was "frying" itself.

 

[DjBobby]

It's a loud whine with a tinny jet-engine kind of sound that's loud enough to hear on a separate floor of your house if other things are quiet, and it's coming from the Mojo itself, not speakers (course there's the EMI issue, that's another issue)

It sounds like this: weeeeeeeeEEEEEEEEEEEEEEEEEEEEE[10minutes]EEEEEEEEEEEEEEEEEEEEEEEeeeeeeeeeeeeeerrrrrrrreeeeeee over the course of last 10 minutes of the charging cycle.

That's how I first heard it - was getting ready for bed on the 2nd level of a house and heard this low volume whine ... I thought it might be a water pipe issue or something outside. I started searching all over the house and eventually discovered it was the Mojo and it was sitting all by itself on a desk in an office with the only connection being the USB charging cable. It was quite loud and noticeable in that room. I was super surprised because it's such a small device with no speaker but that thing is LOUD. Course I freaked out thinking it was going to start a fire (cause as we all know it gets pretty hot) and the next day did a bunch of research and found out it was "normal".

After a bunch of experimenting I could repeat the whine every time - again, just the Mojo and a charging cable.

I have M040XXX, no whining at all. Nothing, dead silent. Should I be concerned that mine is maybe not original?

 

[RiseFall123]

I have M040XXX, no whining at all. Nothing, dead silent. Should I be concerned that mine is maybe not original?

Could you report your cables and charger?

Is still the Onkyo HF player the only fully compatible app for iOS and Mojo for higher sample rate?

 

[MementoMori99]

Could you report your cables and charger?

I use a 3-ft. Anker Powerline micro usb cable and have used it with a 12W Apple charger, Anker Powerport 2 charger and Tronsmart charger. Fortunately, for me, I have not experienced any noise issues whatsoever while charging my Mojo. FYI, I have M056XXX.

https://www.amazon.com/gp/product/B012VWH6PQ/
https://www.amazon.com/gp/product/B01LCDT7FC/
https://www.amazon.com/Tronsmart-Charger-Charge-Technology-Galaxy/dp/B01MYWP60T/

 

[DjBobby]

Could you report your cables and charger?

Is still the Onkyo HF player the only fully compatible app for iOS and Mojo for higher sample rate?

Samsung charger from Aliexpress 2A, cable which I got with the FiiO X5II.
I have Onkyo HF, Hiby and Flac Player (by Dan Leehr) - all work on higher sample rates with iPhone 7 on latest iOS and Mojo.

 

[RiseFall123]

I have Onkyo HF, Hiby and Flac Player (by Dan Leehr) - all work on higher sample rates with iPhone 7 on latest iOS and Mojo.

Since my favourite (foobar) won't play on higher sample rates, what is your fav of those three? The first is mentioned even of the Mojo manual.

 

[RiseFall123]

I use a 3-ft. Anker Powerline micro usb cable and have used it with a 12W Apple charger, Anker Powerport 2 charger and Tronsmart charger. Fortunately, for me, I have not experienced any noise issues whatsoever while charging my Mojo. FYI, I have M056XXX.

https://www.amazon.com/gp/product/B012VWH6PQ/
https://www.amazon.com/gp/product/B01LCDT7FC/
https://www.amazon.com/Tronsmart-Charger-Charge-Technology-Galaxy/dp/B01MYWP60T/

I think that the issue is not related to the chargers because I also use the Apple 12W (iPad Pro).

I will buy those cables from Anker (not only for charge, but also for listening), since the other adviced here Monoprice seem to be difficult to find in my country at normal prices.

 

[DjBobby]

Since my favourite (foobar) won't play on higher sample rates, what is your fav of those three? The first is mentioned even of the Mojo manual.

Onkyo HF. You might need the pro pack.

 

[RiseFall123]

Onkyo HF. You might need the pro pack.

I will get it, thank you.

 

[Wildcatsare1]

Could you report your cables and charger?

Is still the Onkyo HF player the only fully compatible app for iOS and Mojo for higher sample rate?

I’m using a Zojoro 40W Charger with the Mojo Cable Kit USB Cable, without a noise, externally or with headphones/CIEMs.

 

[GrussGott]

I will get it, thank you.

FWIW I decided to do the refund after having spent some quality time with the Eitr > Mimby > Jot ... whoa. Try some Dylan LeBlanc or Angus & Julia Stone on that - just no comparison to the little Mojo, but not fair given we're talking desktop vs a mobile solution and $830 vs $530 new. If I needed a lot of mobile I'd definitely keep the Mojo.

Nevertheless I just won't be going mobile that much so I decided to anchor to the desktop.

 

[435279]

I think that the issue is not related to the chargers because I also use the Apple 12W (iPad Pro).

You are correct, If Mojo users are experiencing charging noise during the last few minutes of charging this is most likely related to the charge circuit switching from a constant current charge mode to a constant voltage charge mode and not an electrically noisy power supply. Lipo batteries similar to the one in Mojo require this as its very important not to exceed a cell voltage of, typically, 4.2v