[Johnsouter]

Yes, they said I needed to go back to the retailer. The retailer can't do anything though as I'm not the original owner.
I thought as a good will gesture and to cover up their poor QC they might have exchanged it for me.

 

[captblaze]

Yes, they said I needed to go back to the retailer. The retailer can't do anything though as I'm not the original owner.
I thought as a good will gesture and to cover up their poor QC they might have exchanged it for me.

Or at least send you a replacement cover to correct their error

 

[Johnsouter]

For a distinguished British brand you would have thought so, wonder if there are any more faulty units out there.

 

[GoldenSound]

2. Is there any difference in SQ/tonality of Mojo2 usb input vs Coaxial input?

The mojo 2 is seemingly a bit sensitive to noise from the source device or PSU.
Jitter performance is top tier on both inputs so that's not going to be an issue, but you probably want to use the lowest noise source you can. This is a rare situation where optical may actually be the optimal choice

 

[Feischmaker]

The mojo 2 is seemingly a bit sensitive to noise from the source device or PSU.
Jitter performance is top tier on both inputs so that's not going to be an issue, but you probably want to use the lowest noise source you can. This is a rare situation where optical may actually be the optimal choice

True, if the source is PC, optical will be the best choice.

By the way, i bought the Mojo 2 this afternoon and I try to check the difference between coax and usb using ibasso DX300 as a source

I found that using the coax input (dx300 coax to mojo 2 coax) resulted in "less analytical" sound than the usb input (dx300 usb c to mojo 2 usb c)

The difference is there but i can't say whether this is driven by the dx300 or because of the Mojo 2.

I don't have another dap with usb and coax to pair with Mojo 2 to further test this

 

[GoldenSound]

True, if the source is PC, optical will be the best choice.

By the way, i bought the Mojo 2 this afternoon and I try to check the difference between coax and usb using ibasso DX300 as a source

I found that the using the coax input (dx300 coax to mojo 2 coax) resulted in "less analytical" sound than the usb input (dx300 usb c to mojo 2 usb c)

The difference is there but i can't say whether this is driven by the dx300 or because of the Mojo 2.

I don't have another dap with usb and coax to pair with Mojo 2 to further test this

Yeah the source itself is the main factor.
Here's some tests I did for example showing it on USB, but one direct to PC, and one with a very low noise isolator.

A fair bit of high frequency hash coming through.
It's fine when connected to my phone though, but that's probably pretty quiet so that'd make sense.

 

[Kentajalli]

I just worry about the long term value, I only purchase it for an upcoming holiday.

In time, it would gain value, as an odd-ball!

 

[Kentajalli]

Yeah the source itself is the main factor.
Here's some tests I did for example showing it on USB, but one direct to PC, and one with a very low noise isolator.



A fair bit of high frequency hash coming through.
It's fine when connected to my phone though, but that's probably pretty quiet so that'd make sense.

Were both the measuring eq. and the PC grounded? I mean is that ground loop noise?
If it is, then disconnecting from the grounded measuring equipment and plugging a headphone instead, would the noise actually flow through, or in other words of any consequence?
I suppose if anyone wants to use the Mojo2 as a desktop DAC, connected to a grounded PC and an amplifier, they should either invest in optical output, or a get an isolator like the Topping device at £50, for USB use.
Easy does it.

 

[GoldenSound]

Were both the measuring eq. and the PC grounded? I mean is that ground loop noise?
If it is, then disconnecting from the grounded measuring equipment and plugging a headphone instead, would the noise actually flow through, or in other words of any consequence?
I suppose if anyone wants to use the Mojo2 as a desktop DAC, connected to a grounded PC and an amplifier, they should either invest in optical output, or a get an isolator like the Topping device at £50, for USB use.
Easy does it.

Yes both are properly grounded.
It's not a ground loop as ground loops will almost always cause 50/60hz noise. Not the high frequency stuff seen here. Additionally using an ungrounded laptop still showed the same issue.

Its related to noise from the source itself not a ground loop.

I'm unsure as to the design of the topping isolator. For the price and size I'd be VERY surprised if it had full optical isolation.
Ill probably buy one to test cause if it is good then it's a very nice option for the money. But sometimes these devices are actually either just ground disconnects, or might be proper galvanic isolation but done via a transformer instead of optically in which case hf noise can still come through.

Optical into the mojo 2 is likely the easiest option in most cases.

 

[Kentajalli]

Yes both are properly grounded.
It's not a ground loop as ground loops will almost always cause 50/60hz noise. Not the high frequency stuff seen here. Additionally using an ungrounded laptop still showed the same issue.
Its related to noise from the source itself not a ground loop.

Then the Intona isolator, should not be able to filter the noise out, am I right? The high frequency noise must be travelling through the ground wires, for any isolator to have an effect, my 2 pence.

I'm unsure as to the design of the topping isolator. For the price and size I'd be VERY surprised if it had full optical isolation.
Ill probably buy one to test cause if it is good then it's a very nice option for the money. But sometimes these devices are actually either just ground disconnects, or might be proper galvanic isolation but done via a transformer instead of optically in which case hf noise can still come through.

Here is more info, and measurements:
I have one, you can borrow it, but I am in London.
http://archimago.blogspot.com/2022/03/measurements-topping-hs01-usb-20.html

Optical into the mojo 2 is likely the easiest option in most cases.

Yep, just a little cumbersome, that's all.
I do that.

 

[GoldenSound]

Then the Intona isolator, should not be able to filter the noise out, am I right? The high frequency noise must be travelling through the ground wires, for any isolator to have an effect, my 2 pence

Noise can come through on any of the lines. (Though issues on data lines are rare, and usually they'd cause obvious dropouts anyway. The 5v/gnd lines are the big concern)

Usually either ground or the 5v line. Just disconnecting ground will not address any issues on other lines.

The intona 7055-C provides <1uV noise on the output.

Ground loops and source noise are separate issues.

 

[Kentajalli]

Noise can come through on any of the lines. (Though issues on data lines are rare, and usually they'd cause obvious dropouts anyway. The 5v/gnd lines are the big concern)
Usually either ground or the 5v line. Just disconnecting ground will not address any issues on other lines.

As you say, noise on the data lines causes dropouts or in Chord case, loud white noise.
The +5V noise, needs to flow through the ground wire to cause any issues, so a ground isolator, such as Intona or Topping can filter it out.
AFAIK, Mojo2 only uses the +5V as a switching signal to go into USB mode (@Rob Watts can debunk that), so noise on it, is not going anywhere, but possible ground wire.
Again, AFAIK noise need to come in and go out (i.e. Flow) to cause a problem, simply existing on one wire is neither here nor there.

The intona 7055-C provides <1uV noise on the output.
Ground loops and source noise are separate issues.

Let's call it ground noise then. What baffles me, is that Intona can filter it out, and all it is, is an isolator.
Perhaps someone else with engineering knowledge, can chip in also.

 

[GoldenSound]

As you say, noise on the data lines causes dropouts or in Chord case, loud white noise.
The +5V noise, needs to flow through the ground wire to cause any issues, so a ground isolator, such as Intona or Topping can filter it out.
AFAIK, Mojo2 only uses the +5V as a switching signal to go into USB mode (@Rob Watts can debunk that), so noise on it, is not going anywhere, but possible ground wire.
Again, AFAIK noise need to come in and go out (i.e. Flow) to cause a problem, simply existing on one wire is neither here nor there.

I'm not sure what the device is doing with the 5v/gnd signals internally. All I can say is that there are some performance gains when using optical or a cleaner source.

Let's call it ground noise then. What baffles me, is that Intona can filter it out, and all it is, is an isolator.
Perhaps someone else with engineering knowledge, can chip in also.

The intona fully isolates all lines both data and power, and provides an exceptionally clean 5V supply

 

[tret]

As with the reply above I also have DCA Aeon Noire that I use sometimes with an original Mojo. Yes it will run them and they sound nice but if pushed hard the Mojo will distort trying to power the Noire. I expect the Stealth and Expanse would be the same or worse.

Run the Aeon on a Schiit Asgard 3 and it will drive them far beyond what the Mojo can manage and there is zero distortion.

Of course the Mojo is very portable if that is what you need but it is a compromise for sure.

FYI Dan Clark himself has stated that Mojo 2 is very powerful and has amazing sound (for a portable DAC/Amp) in response to my question about driving Expanse.

https://www.head-fi.org/threads/dan...measurements-impressions.964852/post-17177323

 

[BS5711]

FYI Dan Clark himself has stated that Mojo 2 is very powerful and has amazing sound (for a portable DAC/Amp) in response to my question about driving Expanse.

https://www.head-fi.org/threads/dan...measurements-impressions.964852/post-17177323

For my information ?

“ …….. for a portable …….. “

That is what I said. Mojo does a good job but it has limitations due to the compromises needed to make it portable.

I have read where Dan Clark said a Schiit Lyr 3 was an excellent choice for his headphones …. 9 watts at 16 Ohms !

Running my Aeon on a Schiit Asgard 3 versus the Mojo and they are driven to another level, zero distortion regardless of volume.

But Asgard 3 has about 8 times the power of a Mojo, is hard to carry in your pocket and the long power cord would become inconvenient