[maxh22]

Finally got my Mojo. I'm stacking with my Nexus 5 for portable use. So far no EMI/interference issues. Also no luck modifying the audio policy file to disable upsampling. However, Uapp with Tidal works pretty damn well. Absolutely no issues on that front so far.

Will be upgrading to Android N tonight to test out resampling behavior. Will report back with findings.

So far Android N only works with the Nexus 5 right?

 

[gnarlsagan]

So far Android N only works with the Nexus 5 right?

We'll not even officially for Nexus 5 actually. I think I can find a test build. It's still in beta and only supports Nexus devices as of yet.

Edit: looks like N is not yet possible on the Nexus 5. Will have to wait for source code to drop with the final release.

Edit2: Just realized I have a freaking Nexus 9. N testing commencing tonight as planned.

 

[kenshinco]

Just got my Mojo delivered.

I'm using iphone so i'm wondering which music app would be best for mojo beside the onkyo?

Thanks.

 

[jmills8]

Just got my Mojo delivered.

I'm using iphone so i'm wondering which music app would be best for mojo beside the onkyo?

Thanks.

N7

 

[maxh22]

We'll not even officially for Nexus 5 actually. I think I can find a test build. It's still in beta and only supports Nexus devices as of yet.

Edit: looks like N is not yet possible on the Nexus 5. Will have to wait for source code to drop with the final release.

Edit2: Just realized I have a freaking Nexus 9. N testing commencing tonight as planned.

Sweet!

 

[NGSKGSncLWHmD9X]

Hello head-fiers,
 
Long time reader but a newbie user here.
 
I must say I am completely content with what Mojo offered me so far.
 
I am using Audirvana+ as my high-end digital playback software and driving my pair of new Sennheiser HD 800 S without any problems AT ALL.
 
Simply amazing. Extreme level of pleasure.
 
Though the reason made me be here is that I am about to go blind due to reading everything written on Mojo. : /
 
Excuse me if this has already been addressed "clearly" but regarding the galvanic isolation and jitter-removal, Rob Watts said if a PC is being used for playback in a desktop setup, Galvanic isolation is a must to avoid the noise due to the use of USB.
 
Now.
I am using a MacBook Pro. It is connected via the hi-speed USB3 cable provided by Chord to my Mojo. Questions:
 
1. Rob said "PC", does that also include laptops? (I guess yes since laptops are also connected to the city circuitry, but just to make sure).
2. In that case, in my current MacBook setup, what should I use? I just ordered AudioQuest Jitterbug, but as I can see, it only removes the jitter and itself not a Galvanic isolator?
3. Rob also mentioned about some benefits back then in using a cable with ferrite jackets. Now, does that mean I should also use a cable with ferrite jacket + AudioQuest to remove the jitter (and plus a possible Galvanic isolator)?
4. I guess the optimal solution is to have some sort of device which provides Galvanic isolation + jitter removal (I think Galvanic isolation also helps out with the removal of jitter, but for now, I'll wait for an expert answer) and plus a ferrite jacket cable?
 
Again, I am sorry if this issue has already been addressed in the last, say, 200 pages (as I have scanned earlier parts but not all).
 
I feel like Gollum gone blind.
 
Thanks in advance.
ng

 

[x RELIC x]

Hello head-fiers,

Long time reader but a newbie user here.

I must say I am completely content with what Mojo offered me so far.

I am using Audirvana+ as my high-end digital playback software and driving my pair of new Sennheiser HD 800 S without any problems AT ALL.

Simply amazing. Extreme level of pleasure.

Though the reason made me be here is that I am about to go blind due to reading everything written on Mojo. : /

Excuse me if this has already been addressed "clearly" but regarding the galvanic isolation and jitter-removal, Rob Watts said if a PC is being used for playback in a desktop setup, Galvanic isolation is a must to avoid the noise due to the use of USB.

Now.
I am using a MacBook Pro. It is connected via the hi-speed USB3 cable provided by Chord to my Mojo. Questions:

1. Rob said "PC", does that also include laptops? (I guess yes since laptops are also connected to the city circuitry, but just to make sure).
2. In that case, in my current MacBook setup, what should I use? I just ordered AudioQuest Jitterbug, but as I can see, it only removes the jitter and itself not a Galvanic isolator?
3. Rob also mentioned about some benefits back then in using a cable with ferrite jackets. Now, does that mean I should also use a cable with ferrite jacket + AudioQuest to remove the jitter (and plus a possible Galvanic isolator)?
4. I guess the optimal solution is to have some sort of device which provides Galvanic isolation + jitter removal (I think Galvanic isolation also helps out with the removal of jitter, but for now, I'll wait for an expert answer) and plus a ferrite jacket cable?

Again, I am sorry if this issue has already been addressed in the last, say, 200 pages (as I have scanned earlier parts but not all).

I feel like Gollum gone blind.

Thanks in advance.
ng

Welcome to Head Fi, sorry about your wallet!!

1. Your laptop is still provided power from the battery, even while it's plugged in (I'm pretty sure), so unless you hear terrible computer noise and interference I wouldn't worry about noise being generated.

2. I'd forget about the Jitterbug with the Mojo. As mentioned, the Mojo is imune to jitter and the Jitterbug has been reported to not really do anything. If you do use the Jitterbug please report back on what difference it makes, if any. Try to be objective.

3. A ferrite choke will help with RF noise, not jitter, particularly from a source connected to a celular network. If you don't hear noise I wouldn't bother. Again, if you try one it would be good to know what you hear if there are any differences with your setup.

4. Galvanic isolation has nothing to do with Jitter and timing. It's strictly for noise from the USB (and coaxial?) source. The reason it's not used in the Mojo is it needs a power source and that's dosen't bode well for a battery operated device meant for portable use. You could purchase a galvanic isolator separately if you have a noisy USB output.

I have been listening through the Mojo with my 2011 MacBook Pro and hear no noise or smearing (jitter) in the music at all. It sounds the same as when connected to my X5ii. I guess it depends on how 'clean' your laptop operates in general and what serial bus the USB port is on the computer. Some USB ports share the same bus as a hard drive, for example, and are quite noisy when the disk accesses data (actually, I'm not sure a galvanic isolator will help in that situation though).

To avoid reading the whole thread just read the third post, which Mython has done a ridiculously good job of gathering relevant information. In particular, the section that's labelled 'Informative posts by Rob'.

 

[wym2]

Welcome to Head Fi, sorry about your wallet!!

1. Your laptop is still provided power from the battery, even while it's plugged in (I'm pretty sure), so unless you hear terrible computer noise and interference I wouldn't worry about noise being generated.

2. I'd forget about the Jitterbug with the Mojo. As mentioned, the Mojo is imune to jitter and the Jitterbug has been reported to not really do anything. If you do use the Jitterbug please report back on what difference it makes, if any. Try to be objective.

3. A ferrite choke will help with RF noise, not jitter, particularly from a source connected to a celular network. If you don't hear noise I wouldn't bother. Again, if you try one it would be good to know what you hear if there are any differences with your setup.

4. Galvanic isolation has nothing to do with Jitter and timing. It's strictly for noise from the USB (and coaxial?) source. The reason it's not used in the Mojo is it needs a power source and that's dosen't bode well for a battery operated device meant for portable use. You could purchase a galvanic isolator separately if you have a noisy USB output.

I have been listening through the Mojo with my 2011 MacBook Pro and hear no noise or smearing (jitter) in the music at all. It sounds the same as when connected to my X5ii. I guess it depends on how 'clean' your laptop operates in general and what serial bus the USB port is on the computer. Some USB ports share the same bus as a hard drive, for example, and are quite noisy when the disk accesses data (actually, I'm not sure a galvanic isolator will help in that situation though).

To avoid reading the whole thread just read the third post, which @Mython has done a ridiculously good job of gathering relevant information. In particular, the section that's labelled 'Informative posts by Rob'.

 
Along with the excellent observations and advice of  x RELIC x, I have found an improvement in SQ in my system by unplugging my mid-2010 MBP and using only one USB port. I experimented and found the best port ( one is better than the other ).
 
 
MBP (Audirvana) → SDragon → Mojo → AQ Sky → LC → HD 800S (WW Platinum)

 

[gnarlsagan]

We'll not even officially for Nexus 5 actually. I think I can find a test build. It's still in beta and only supports Nexus devices as of yet.

Edit: looks like N is not yet possible on the Nexus 5. Will have to wait for source code to drop with the final release.

Edit2: Just realized I have a freaking Nexus 9. N testing commencing tonight as planned.

Apparently Android N developer preview 3 doesn't have working USB audio out. Couldn't get my Nexus 9 to recognize either the Mojo or the UHA760. Tried going into developer settings and changing the USB setting to "Audio Source" to no effect. Looks like N is a no go for now. Hopefully that means Google is still rehauling the audio system for N.

 

[SearchOfSub]

something I don't understnd. I am using usb port from pc to mojo, and when playing through usb if I connect coaxial cable to it (on top of it), though source is still only usb connection, audio quality is much better. I am using Audioquest "exotic" coaxial cable plugged just plugged in, playing through normal usb cable. And this ain't no placebo. Anyone have experience like this

 

[warrior1975]

I'm going to purchase another optical cable. Only using it for audio from my TV and/or my cable box to watch movies. I need a longer one, 10ft. It doesn't matter much, for which type?

 

[x RELIC x]

I'm going to purchase another optical cable. Only using it for audio from my TV and/or my cable box to watch movies. I need a longer one, 10ft. It doesn't matter much, for which type?

The quality of the cable will determine the data throughput. If there are dropouts then you may only be able to use 24/96 or less instead of 24/192. The light must travel through the fibre optic (plastic or glass) with as little in the way of dispersion as possible. With optical cables quality kind of really does matter. You can look for high quality multi strand plastic if you think you will need bends in the cable. Sysconcept can make you the cable you want.

 

[warrior1975]

x RELIC x OK, thanks brother. Ill check them out. Any idea what a TV or cable box puts put through the optical out?

 

[NGSKGSncLWHmD9X]

Welcome to Head Fi, sorry about your wallet!!

 
Thanks. I guess that was a reference to my HD 800 S, eh ? : p
 

1. Your laptop is still provided power from the battery, even while it's plugged in (I'm pretty sure), so unless you hear terrible computer noise and interference I wouldn't worry about noise being generated.

 
I don’t hear noise from the computer at all, as Macs are usually exceptionally silent. Resolved! : )
 

2. I'd forget about the Jitterbug with the Mojo. As mentioned, the Mojo is imune to jitter and the Jitterbug has been reported to not really do anything. If you do use the Jitterbug please report back on what difference it makes, if any. Try to be objective.

 
Immune to jitter? I thought only Chord's desktop DACs (Dave, TT etc.) were immune to jitter but not Mojo (as possibly as I could remember from Rob's earlier posts).
 
I will test and report once received.
 

3. A ferrite choke will help with RF noise, not jitter, particularly from a source connected to a celular network. If you don't hear noise I wouldn't bother. Again, if you try one it would be good to know what you hear if there are any differences with your setup.

 
In my setup then, I will definitely not require a ferrite jacket cable as I am not using any cellular device for playback. Resolved.
 

 
4. Galvanic isolation has nothing to do with Jitter and timing. It's strictly for noise from the USB (and coaxial?) source. The reason it's not used in the Mojo is it needs a power source and that's dosen't bode well for a battery operated device meant for portable use. You could purchase a galvanic isolator separately if you have a noisy USB output.

 
Wait, you mean Galvanic isolation is only to eliminate RF related noise issues in the use of RF generating devices such as mobile phones? Confused. I thought PCs definitely needed isolation as per Rob's post below.
 

  To eliminate the RF and signal correlated noise on USB you need galvanic isolation. The downside to galvanic isolation is that it draws power from the source - which is not something we can do with a mobile product. All Chord desktop DAC's have USB galvanic isolation now.
 
That said, mobile sources are much lower noise - they have very efficient processors, unlike a PC, and there is no ground, so circulating currents are much less, so it is a much smaller problem with mobile. If you can do it, use the optical, as this usually sounds the best and is completely isolated. Optical has a undeservedly poor reputation, as it sounds much smoother and darker than other inputs, and this is just a feature of lower noise floor modulation - its smoother with better instrument separation and focus - but lack of glare is often confused with a lack of detail resolution. Listening tests must be done with a lot of care, as it is easy to draw the wrong conclusions!
 
Rob

 

 
To avoid reading the whole thread just read the third post, which @Mython has done a ridiculously good job of gathering relevant information. In particular, the section that's labelled 'Informative posts by Rob'.

 
I did. Still in the dark (a bit).
 
Thanks for your responses again. Much appreciated.

 

[x RELIC x]

Thanks. I guess that was a reference to my HD 800 S, eh ? : p


I don’t hear noise from the computer at all, as Macs are usually exceptionally silent. Resolved! : )


Immune to jitter? I thought only Chord's desktop DACs (Dave, TT etc.) were immune to jitter but not Mojo (as possibly as I could remember from Rob's earlier posts).

I will test and report once received.


In my setup then, I will definitely not require a ferrite jacket cable as I am not using any cellular device for playback. Resolved.


Wait, you mean Galvanic isolation is only to eliminate RF related noise issues in the use of RF generating devices such as mobile phones? Confused. I thought PCs definitely needed isolation as per Rob's post below.



I did. Still in the dark (a bit).

Thanks for your responses again. Much appreciated.

Yes, the Mojo implementation and solution for jitter is very much the same as the Hugo, Hugo TT, and DAVE. The 2Qute, TT, and DAVE have galvanic isolation.

4. No, galvanic isolation resolves RF noise from noisy computers, etc., just not jitter.

Spoiler: Rob on Jitter

Originally Posted by Rob Watts View Post

Quote:
Originally Posted by Skyyyeman View Post

Clock jitter -- What is clock jitter? The reason I ask is that in considering different DAPs to use as transports to output a digital signal to the Mojo, I've seen some varying specs for clock jitter on different DAPs, as follows:

AK100 90 ps (pico seconds)
AK120 50 "
AK240 50 "

Question: Does clock jitter degrade the digital signal before it's send out from the DAP? Or are they referring to clock jitter of the internal dac, in which case clock jitter doesn't matter since the signal never reaches the dac (it's been output beforehand)?

If clock jitter degrades the signal before it's sent out, then it appears that the AK100 is not as good a transport as the other two. But would the difference be discernible?

Thx

Clock jitter is timing uncertainty (or inaccuracy) on the main clock that is feeding the digital outputs. Its often expressed as cycle to cycle jitter as an RMS figure, but can be total jitter which includes low frequency jitter too. Total jitter is the most important specification. If you want here is a good definition:

https://en.wikipedia.org/wiki/Jitter

As you can see, the jitter subject can get complicated and its often abused by marketing...

But with all of my DAC's you do not need to worry at all about source jitter, so all of the above AK numbers are fine. So long as its below 2uS (that is 2,000,000 pS) you are OK, and nobody has jitter that bad!

Rob

Quote:
Originally Posted by Rob Watts View Post

The reasons why sources and digital interconnects sound different are well understood - see some of my posts. In a nutshell it is not jitter (all my DACs are completely immune to source jitter) but down to RF noise and distorted currents from the source flowing into the DAC's ground plane. The RF noise inter-modulates with the analogue electronics, creating random noise as a by product, which creates noise floor modulation, and that makes it sound brighter or harder. The correlated or distorted currents very subtly add or subtract to small signals, thus changing the fundamental linearity, which in turn mucks up depth perception.

But I also agree in that lots of people hear changes that are not there - I for one have never heard any difference with optical cables (assuming all are bit perfect) with my DAC's, but lots of folks claim big differences. Placebo, or listening with your wallet, plays a part here. Then there are cases of people preferring more distortion... Listening tests must be done in a very controlled and careful fashion, particularly if you are trying to design and develop things.

Rob