Chord Mojo(1) DAC-amp ☆★►FAQ in 3rd post!◄★☆

[Tympan]

I was wondering why the only time I feel jitter is when I have too much coffee, makes sense now! Merci pour ces infos

 

[Delayeed]

 
In order to better illustrate the differences regarding RF noises interaction with a standard USB cable (1m) and a standard optical fiber (1.5m) I measured the jitter in both cases.
 
My rig is the following:
 
° 11.025 KHz 16 bit wav jitter file
° Mojo is AC powered
° The jitter signal is entering Mojo via USB or SPDIF/Toslink optical input
° Mojo's headphone output is entering my desktop 16bit/44.1Khz Line In ( computer playing the role of ADC Analog to Digital Converter, Davina not available

)
° Jitter software = Musiscope
 
1° Jitter with USB cable
 

 
 
2° Jitter with Toslink Optical
 

 
 
In my RF noisy environment, using Toslink Optical is improving the jitter by roughly 25 dB .
 
Please do note that the test bench allows you to compare the differences of jitter depending on Mojo's input used or even compare USB cables in a Jitter point of view.
With a proper test equipment the Noise Floor here measured at around - 120dB should lower significantly.
 
According to some studies jitter is noticed by human ear for values greater than 10ns ( around -90db in above drawings ).
Maybe it is one of the reasons I am still listenning through USB cable with this setup.

 
Cheers.

Wow I had no idea it was possible to do this without some fancy gear. Thanks so much will try this myself

 

[Delayeed]

1.0m 2$ USB Jitter:
 

 
 


1.0m 10$ Optical Jitter:

 
 
EDIT: K fixed... seems like optical is better in this case however inaudible it is haha.

Also some other measurements:

Here is the optical when Charging:



Here is Optical on battery power:



Charging and Battery powered jitter measurements are same but I think once it starts making
that buzzing sound is when it also measures worse as seen above.

 

[raelamb]

I own the L-19 and the Lavricable cable interconnect. Both work intermittently and require resets of the iDevice to make it work sometimes. The only full proof solution I have found to the Apple Camera kit is the Lightning Pure Silver Decoding cable from Penon Audio in Hong Kong.

http://penonaudio.com/Lightning-Pure-Silver-Decoding-Cable

Yes, it is expensive at $130 but it functions exactly like an Apple cable every time all the time. For over a month whether it is hard resets, soft resets, turning it off or iOS updates whatever it works perfectly. And before anyone asks and not to inflame the cable debate, yes it sounds materially better than the Apple Camera Kit.

Reposting:
 

This is exactly my experience.The L19 and the lavricable were both wonky. The http://penonaudio.com/Lightning-Pure-Silver-Decoding-Cable is 100% on the money!
 
I now feel no need to buy the Chord add-on for just the ergonomics. I'll wait for the next one

 

[Mediahound]

I recently got this new Lightning to USB3 Camera Adapter and although it's larger, it allows me to charge my iPhone at the same time as listening, which I like. It sounds and works great and seems sturdy, etc. 
 
 
http://amzn.to/1XCitm9

 

[canali]

excuse me guys if you've already read this stereolife jan/16 article featuring john franks of chord.
..in it he talks about chord's unique approaches to fidelity, chip design and the development of 
dave, hugo, and of course the mojo... and where he thinks personal audio is going.
(tidbit: get ready for your do it all smartphones to have really really big storage capacities)
I recently saw a video with him and Rob in which they had talked of similar items.
 
http://www.stereolifemagazine.com/interviews/item/1165-john-franks-chord-electronics
 

 
excerpt:

Isn't it a waste putting this whole design into something so small as the Mojo?

Oh I think such products have a great future. In case of the Mojo, I wanted it to be something really unique, like a pebble just with buttons and stuff. Even the feel of the thing is something you would remember, or the fact that the ball rotates. It doesn't do anything, it could have been a normal button but it's just nicer this way. I just wanted it to be something people would like to hold and play with. The reason we managed to get it to such a low price is because we've negotiated really, really hard not only with our subcontractors, but with all of their suppliers. The chips used in it, at a low volume, would cost about the same as this whole product, where actually we got really good deals but we had to commit to massive volumes.

On the web there's been a large amount of press and people saying it's (mojo) a DAP, but you see I don't believe that DAPs have got a really long life because everyone carries a phone. Personally I like DAPs, I like the way they play, but if we apply the Moore's Law again, the amount of memory and computing power we have in our phones now will be nothing compared to what we will have in five years time. It's going to be massive, we are going to use our phones for things we wouldn't dare try today. Like listening to hi-res music for instance. So if you have a really great DAC now, you can use your phone as a source already. I have 128 GB on my phone now, so the next one after that will probably have 512 GB or 1 TB. Combine it with the network speeds you get, and listening to hi-res music is fairly simple.

So the Mojo is built primarily for mobile phone users?

What we want to achieve with the Mojo is not to win against our competitors, but to convince everyone to switch to high quality music. Because it can be really easy. All you need for a start is this relatively cheap device, a good phone with some music on it and a pair of descent headphones. And you can experience something really great. I believe that half of the people in the world are audiophiles, on some level of course. And having visited lots of places I know there are many, many poor people in the world. They have good lives but they just don't have the money we have. So in a way I wanted to democratize the world with the Mojo, because really all of these people have smartphones, but the music from a smartphone is poor. So what's there to stop you from buying a Mojo? You just plug this little thing into that little thing and wow - you've got a concert hall in front of you.

----------------------

ps...if anyone in Canada is willing to unload one please shoot me a PM

 

[Xcalibermj]

The L19 cable is a hit and miss with the iPhone and IPad . I get interference occasionally and that is a big negative. It works fine in the airplane mode though. Can see myself using it on flights only. The CCk has no problems at all apart from portability issues. The penoaudio cable looks interesting as they claim to use the connector with the chip intact from an original CCK. Will wait for some impressions before pulling the trigger on this one. I have ordered the otg from penoaudio though for use with android.

 

[jmills8]

A/B tested X3/mojo/coaxl Vs Phone/mojo/otg. Both sounds great with very good details but X3 set up more balanced, less bass impact and less treble extension.Phone set up wider sound stage, feels being more upfront to the stage, deeper bass with more bass impact and treble is more pronounced.

 

[Arpiben]

1.0m 2$ USB Jitter:

 







1.0m 10$ Optical Jitter:




EDIT: K fixed... seems like optical is better in this case however inaudible it is haha.


Also some other measurements:


Here is the optical when Charging:





Here is Optical on battery power:





Charging and Battery powered jitter measurements are same but I think once it starts making

that buzzing sound is when it also measures worse as seen above.

Hi Delayeed,
Thanks for the data.I just discovered the feature a few days ago and didn't have time to play more with.
Regarding the lower band of the spectrum, I noticed that this area is more prone to some noises. Power supply,desktop noise variation,RF noise from Output - Line In cable ....I don't know.
Time for coffee now. Otherwise,as mentioned by @Tympan my own jitter will be out of specs. Cheers

 

[jmills8]

Mojo portable storage.

 

[Ike1985]

Has anyone found a good cable that can remove all or most of the RF/EMI interference from their phones?  Before you recommend one, please go to an area where you have a very poor signal and use MOJO and report because there is a huge difference in RF interference between a good and poor signal.

 

[Rob Watts]

 
In order to better illustrate the differences regarding RF noises interaction with a standard USB cable (1m) and a standard optical fiber (1.5m) I measured the jitter in both cases.
 
My rig is the following:
 
° 11.025 KHz 16 bit wav jitter file
° Mojo is AC powered
° The jitter signal is entering Mojo via USB or SPDIF/Toslink optical input
° Mojo's headphone output is entering my desktop 16bit/44.1Khz Line In ( computer playing the role of ADC Analog to Digital Converter, Davina not available

)
° Jitter software = Musiscope
 
1° Jitter with USB cable
 

 
 
2° Jitter with Toslink Optical
 

 
 
In my RF noisy environment, using Toslink Optical is improving the jitter by roughly 25 dB .
 
Please do note that the test bench allows you to compare the differences of jitter depending on Mojo's input used or even compare USB cables in a Jitter point of view.
With a proper test equipment the Noise Floor here measured at around - 120dB should lower significantly.
 
According to some studies jitter is noticed by human ear for values greater than 10ns ( around -90db in above drawings ).
Maybe it is one of the reasons I am still listenning through USB cable with this setup.

 
Cheers.

 
Sorry but you can't hope to measure Mojo's jitter performance using the ADC on your computer. All you will be measuring is noise pick-up within the PC, not Mojo at all.
 
Using an APX555 and the 24 bit J-test file at 48k I get with optical:
 

There are some asynchronous jitter components just visible at -160dB.
 
With USB we get:
 

In this case no asynchronous jitter components as timing comes from the FPGA, but there is some data related components at -150dB. This is due to my very noisy Dell that I use for running the AP. If we were to use a mobile source these components would be much smaller - and eliminated with galvanic isolation.
 
That said, I do not know of any other non Chord DAC (at any price) that has such low levels of measured jitter from the J-test 
 
Rob

 

[Arpiben]

   
Sorry but you can't hope to measure Mojo's jitter performance using the ADC on your computer. All you will be measuring is noise pick-up within the PC, not Mojo at all.
 
Using an APX555 and the 24 bit J-test file at 48k I get with optical:
 

There are some asynchronous jitter components just visible at -160dB.
 
With USB we get:
 

In this case no asynchronous jitter components as timing comes from the FPGA, but there is some data related components at -150dB. This is due to my very noisy Dell that I use for running the AP. If we were to use a mobile source these components would be much smaller - and eliminated with galvanic isolation.
 
That said, I do not know of any other non Chord DAC (at any price) that has such low levels of measured jitter from the J-test 
 
Rob

 
Sorry but I never intended or pretended to measure the real jitter values with such!
 
I even wrote, in bad english probably, the following:
Please do note that the test bench allows you to compare the differences of jitter depending on Mojo's input used or even compare USB cables in a Jitter point of view.
With a proper test equipment the Noise Floor here measured at around - 120dB should lower significantly.
 
I wanted to show the differences between feeding Mojo with a standard USB cable vs an optical fiber in a noisy RF environement.
 
Anyhow, thanks for the data you provided as well as this clarification for no misunderstandings.I perfectly understand your point.
Best Regards.

 

[Rob Watts]

Cool, no problem. But it exposes the problem of measurements in that it just relates to that test gear at that time. Interpreting things can get tricky when the test equipment residual is the same as the unit being tested, and impossible when the test equipment is worse than the unit being tested.
 
Rob

 

[Rowethren]

Mojo portable storage.

Looks nice! But doesn't that move around a fair bit in transit? It doesn't look that tight against the Mojo. I would probably be tempted to pad it out with foam to keep everything stationery.