[BS5711]

It’s as simple as adding a mute function when the USB synchronization fails. Remember, Chord DACs all share the same USB firmware and it isn’t simply a Mojo 2 issue— though, it seems to be far more prevalent in that device.

Post 5693 above talks of it happening through coaxial and in my Mojo white noise episode there was nothing happening that was any sort of interruption or change in the USB data transfer that is said to cause the problem, I was swapping headphones back and forth mid song.

If you have it figured out then obviously so do Chord and if it was “….. as simple as adding a mute function …..” while they may not offer a firmware fix for Mojo why would they not have implemented a mute function in Mojo 2 somewhere in the 5 or so year development period ?

Based on my experience with white noise on three different DACs, and the variations in comments in this thread about different people’s experience with what seemed to cause it with Mojo 2, I contend that it is not just a USB glitch with a simple mute function fix, that just doesn’t make any sense to me.

 

[miketlse]

It’s as simple as adding a mute function when the USB synchronization fails. Remember, Chord DACs all share the same USB firmware and it isn’t simply a Mojo 2 issue— though, it seems to be far more prevalent in that device.

I think many Chord owners have no problem with your identification of the cause of the symptoms being a failure in USB synchronisation.
Unfortunately a failure in USB synchronisation, can have many root causes and a quick read of this thread (and other Chord threads) gives a good 'feel' for the normal culprits as root causes.

In many respects this is the old computer acronym GIGO at work.

Where you and I differ, is that your preferred solution is for Chord to mute the output, so in effect the GI still continues, but the GO is muted.

In contrast my preferred solution is to prevent the GI in the first place, and then the GO does not happen.
I sense that this is Chords preference, partly because they are so quiet/tight-lipped and provide little feedback about firmware updates to solve the issue.
Anyone who reads @Rob Watts thread/posts will already know that firmware updates will normally be non-existant.

The downside is that preventing GI is more complex to put in place:

• I think owners by default find it easier to understand single-causes to single-issues
• For failure in USB synchronisation, which can have multiple alternative causes, inevitably confuses many of the above owners
• My work experience from managing user support in aerospace, is that we (ideally Chord, but it feels like it will fall on the shoulders of enthusiastic head-fiers) need to provide some form of user guidance/awareness/user help on this issue (like the early years of the Mojo thread) - maybe this just needs to be a simple forum thread, containing a table containing the potential causes of failure in USB synchronisation, plus how to mitigate them. Inevitably this table can never be 100% finished, because human ingenuity will always be able to discover new ways to trip up the Mojo2.

Just my view, and it does depend on multiple owners being interested enough to contribute some of their time to populate info etc.

 

[BS5711]

I think many Chord owners have no problem with your identification of the cause of the symptoms being a failure in USB synchronisation.
Unfortunately a failure in USB synchronisation, can have many root causes and a quick read of this thread (and other Chord threads) gives a good 'feel' for the normal culprits as root causes.

In many respects this is the old computer acronym GIGO at work.

Where you and I differ, is that your preferred solution is for Chord to mute the output, so in effect the GI still continues, but the GO is muted.

In contrast my preferred solution is to prevent the GI in the first place, and then the GO does not happen.
I sense that this is Chords preference, partly because they are so quiet/tight-lipped and provide little feedback about firmware updates to solve the issue.
Anyone who reads @Rob Watts thread/posts will already know that firmware updates will normally be non-existant.

The downside is that preventing GI is more complex to put in place:

• I think owners by default find it easier to understand single-causes to single-issues
• For failure in USB synchronisation, which can have multiple alternative causes, inevitably confuses many of the above owners
• My work experience from managing user support in aerospace, is that we (ideally Chord, but it feels like it will fall on the shoulders of enthusiastic head-fiers) need to provide some form of user guidance/awareness/user help on this issue (like the early years of the Mojo thread) - maybe this just needs to be a simple forum thread, containing a table containing the potential causes of failure in USB synchronisation, plus how to mitigate them. Inevitably this table can never be 100% finished, because human ingenuity will always be able to discover new ways to trip up the Mojo2.

Just my view, and it does depend on multiple owners being interested enough to contribute some of their time to populate info etc.

A poster above indicated that he got while noise using a coaxial input.

I have no knowledge of the technical aspects of this but here goes .............

Does the coaxial input completely bypass the USB ? If it does and the problem is with USB how can the problem happen through coaxial ?

Does perhaps a failure in USB synchronization cause a problem further down the line and that is the actual problem that causes the white noise ? That is the failure in USB synchronization is also a trigger but that failure can in turn be triggered by other factors ??

Perhaps some other issue with coaxial can cause the same problem deeper in the system not at the data transfer stage ?

Sorry if I am not making proper sense, I know what I am trying to convey but I am not sure it is conveyed clearly to those with a technical understanding of the matter.

 

[miketlse]

A poster above indicated that he got while noise using a coaxial input.

I have no knowledge of the technical aspects of this but here goes .............

Does the coaxial input completely bypass the USB ? If it does and the problem is with USB how can the problem happen through coaxial ?

Does perhaps a failure in USB synchronization cause a problem further down the line and that is the actual problem that causes the white noise ? That is the failure in USB synchronization is also a trigger but that failure can in turn be triggered by other factors ??

Perhaps some other issue with coaxial can cause the same problem deeper in the system not at the data transfer stage ?

Sorry if I am not making proper sense, I know what I am trying to convey but I am not sure it is conveyed clearly to those with a technical understanding of the matter.

I sense what you are trying to say (but there is always the chance that I am misinterpreting things).
In simple terms Rob has posted that for many of his Dacs, the 'input buffer chips/software' are reused (to my engineering brain, once you have a stable input buffer capability, don't try and reinvent the wheel for each new product).

These input buffers handle USB, coaxial, and optical, and then forward the data to the FPGA.
I focussed on USB because that felt to me like the predominant source in the earlier posts.

So it is true that some issues in coax can potentially cause downstream problems in the FPGA.

I think it would be equally valid to include coaxial issues in the table of issues/mitigation.

One of the key lessons that a manager told me in France was 'do not forget the end goal' - here the end goal is to provide the correct inputs to the FPGA, so we need to include usb and coaxial, plus in theory optical, but there seem to be zero complaints from optical users.

 

[BS5711]

I sense what you are trying to say (but there is always the chance that I am misinterpreting things).
In simple terms Rob has posted that for many of his Dacs, the 'input buffer chips/software' are reused (to my engineering brain, once you have a stable input buffer capability, don't try and reinvent the wheel for each new product).

These input buffers handle USB, coaxial, and optical, and then forward the data to the FPGA.
I focussed on USB because that felt to me like the predominant source in the earlier posts.

So it is true that some issues in coax can potentially cause downstream problems in the FPGA.

I think it would be equally valid to include coaxial issues in the table of issues/mitigation.

One of the key lessons that a manager told me in France was 'do not forget the end goal' - here the end goal is to provide the correct inputs to the FPGA, so we need to include usb and coaxial, plus in theory optical, but there seem to be zero complaints from optical users.

You understood what I was trying to convey and it sounds like I was thinking along the right lines. That is the issue isn’t entirely USB related but more the next stage along the data path so that a variety of different scenarios through different inputs could conceivably trigger the issue.

I guess that is why a fix wasn’t implemented in Mojo 2 if a proper fix isn’t a simple muting.

Is it technically possible that repeated unplugging and plugging back in of headphones every 10 - 15 seconds or so with the same song being streamed via an iPad mini 6 (USB-C) could trigger the problem ? That is what happened in my case, I am 99% certain there were no other changes, no bumped USB cable, no change in music file, literally in the middle of the same song, white noise after half a dozen or some unplug and plug back in cycles of the headphones I was A-B testing.

 

[iDesign]

I think many Chord owners have no problem with your identification of the cause of the symptoms being a failure in USB synchronisation.
Unfortunately a failure in USB synchronisation, can have many root causes and a quick read of this thread (and other Chord threads) gives a good 'feel' for the normal culprits as root causes.

In many respects this is the old computer acronym GIGO at work.

Where you and I differ, is that your preferred solution is for Chord to mute the output, so in effect the GI still continues, but the GO is muted.

In contrast my preferred solution is to prevent the GI in the first place, and then the GO does not happen.
I sense that this is Chords preference, partly because they are so quiet/tight-lipped and provide little feedback about firmware updates to solve the issue.
Anyone who reads @Rob Watts thread/posts will already know that firmware updates will normally be non-existant.

The downside is that preventing GI is more complex to put in place:

• I think owners by default find it easier to understand single-causes to single-issues
• For failure in USB synchronisation, which can have multiple alternative causes, inevitably confuses many of the above owners
• My work experience from managing user support in aerospace, is that we (ideally Chord, but it feels like it will fall on the shoulders of enthusiastic head-fiers) need to provide some form of user guidance/awareness/user help on this issue (like the early years of the Mojo thread) - maybe this just needs to be a simple forum thread, containing a table containing the potential causes of failure in USB synchronisation, plus how to mitigate them. Inevitably this table can never be 100% finished, because human ingenuity will always be able to discover new ways to trip up the Mojo2.

Just my view, and it does depend on multiple owners being interested enough to contribute some of their time to populate info etc.

Muting the audio signal is also a useful hearing safety feature anytime a cable is accidentally disconnected or the synchronization fails. There is no good reason for it not to exist irrespective of the white noise problem. It seems unlikely that Chord will ever address the issue and it’s one of the many reasons I have long wished they would support firmware updates. Hopefully it will be fixed in the Ultima DAC and Choral M Scaler...

 

[dsrk]

You understood what I was trying to convey and it sounds like I was thinking along the right lines. That is the issue isn’t entirely USB related but more the next stage along the data path so that a variety of different scenarios through different inputs could conceivably trigger the issue.

I guess that is why a fix wasn’t implemented in Mojo 2 if a proper fix isn’t a simple muting.

Is it technically possible that repeated unplugging and plugging back in of headphones every 10 - 15 seconds or so with the same song being streamed via an iPad mini 6 (USB-C) could trigger the problem ? That is what happened in my case, I am 99% certain there were no other changes, no bumped USB cable, no change in music file, literally in the middle of the same song, white noise after half a dozen or some unplug and plug back in cycles of the headphones I was A-B testing.

When I was ABing with M11 Pro I did unplug/replug very fast but I didn't experience any white noise. I was using optical input though.

The white noise issue seems to be much more complicated and dreadful than I thought. Is it beyond Chord's ability to fix the issue? I don't know.

I can't imagine how dreadful and dangerous the issue could be for people who use sensitive IEMs.

 

[cybergalaxy]

I agree, it's all about taste and preferences. Your best sounding headphone can be worst sounding for me.

@RPJ12
HD6XX headphones warmer and forward vocal sounding but it's hard to find a better alternative if you into mids and vocals. HD6XX pairs excellent with Mojo 2 with a little bit of EQ, it's best pairing for me.

What is your EQ setting for HD6xx if happy to share?

 

[dsrk]

What is your EQ setting for HD6xx if happy to share?

Sure, my EQ for HD6XX is simple:
20hz: 2db (red)
20khz: 3db (orange)

If you feel the vocals are a little forward add this also:
3khz: -1db (light red) or -2db (red)

 

[cybergalaxy]

Sure, my EQ for HD6XX is simple:
20hz: 2db (red)
20khz: 3db (orange)

If you feel the vocals are a little forward add this also:
3khz: -1db (light red) or -2db (red)

Thank you!

 

[cybergalaxy]

Where do you get th

This is very helpful! Where do you get this info from please?

 

[MaiLam]

This is a silly question, but having a hard time finding a clear answer. I’m charging a Mojo 2, and can’t tell when fully charged or not. The micro usb charging light is blue, and the ‘quality of charge‘ orb is pale blue. The manual says the battery is fully charged when showing a blue led light, but is that not the same as the ‘75-100% charged’ blue light?

 

[rwelles]

When it's charged to 100%, the power orb will turn purple.

 

[MaiLam]

When it's charged to 100%, the power orb will turn purple.

Even when turned off and not in use otherwise, just in ‘charging’ mode? Thanks!

 

[Gus141]

…potential causes of failure in USB synchronisation, plus how to mitigate them… Inevitably this table can never be 100% finished…, and it does depend on multiple owners being interested enough to contribute some of their time to populate info etc.

The more examples we have the better. So here is my experience with the white noise issue:

I never experienced white noise in almost 3 months of ownership until today; I use the Mojo2 almost exclusively with a 2021 iPad Pro 12.9” via USB; the USB cord is very tight fitting and I don’t move the DAC around much when I’m listening. I had never used the ”Lock Control“ setting before [magenta menu button color] and wanted to try it out. After enabling it (+ & - buttons together) and proving to myself the controls were truly locked, I turned it off (pressed Menu button to be taken immediately to the lock-down control, then + & - at the same time) and immediately got the white noise. Unplugging the USB from the iPad and replugging in corrected the issue.

Now maybe the act of pressing the + & - simultaneously stressed the USB connection. But I have tried to re-enable and then disable lock control multiples times and have not recreated the white noise.

Only 1 white noise incident in 3 months of daily use. I can live with that. Especially since the volume is only at the volume set — it does not max out the volume, like another DAC did when switching a setting (DAC to go unnamed since they fixed it with a Firmware update [I really wish Chord would embrace the concept of firmware updates and not just for their 3rd-party developed stuff like the Poly]).