Chord Mojo(1) DAC-amp ☆★►FAQ in 3rd post!◄★☆
Dec 11, 2017 at 3:42 PM Post #34,741 of 42,758
no one considered poly as ultimate source?
 
Dec 11, 2017 at 5:09 PM Post #34,743 of 42,758
Sorry if this is a repeat question but holy cr&p there’s over 2300 pages in this thread! :wink:

I’m looking for a short optical interconnect to use for portable use for stacking a source to the mojo. Does anyone have any good tips for a reasonably priced option?

So far I’m struggling to find much around under 0.5m in length:
• Fiio L12S short (described as 7cm or 16 cm end-to-end). This looks perfect but is discontinued.
• ALO audio portable optical cable: perfect, cheap, but shipping is $40 USD for a $20 USD cable!
• Moon audio: too expensive

There’s custom options from the likes of Sys concepts but I’m looking for an off-the-shelf option to keep the price down. Any ideas greatly appreciated!
 
Dec 11, 2017 at 5:15 PM Post #34,744 of 42,758
^^ I've had good luck with Dyson Cables, they are great to work with and modestly priced, high quality cables.
 
Dec 11, 2017 at 5:26 PM Post #34,745 of 42,758
Sorry if this is a repeat question but holy cr&p there’s over 2300 pages in this thread! :wink:

I’m looking for a short optical interconnect to use for portable use for stacking a source to the mojo. Does anyone have any good tips for a reasonably priced option?

So far I’m struggling to find much around under 0.5m in length:
• Fiio L12S short (described as 7cm or 16 cm end-to-end). This looks perfect but is discontinued.
• ALO audio portable optical cable: perfect, cheap, but shipping is $40 USD for a $20 USD cable!
• Moon audio: too expensive

There’s custom options from the likes of Sys concepts but I’m looking for an off-the-shelf option to keep the price down. Any ideas greatly appreciated!

Super short optical would require a quality implementation to avoid light diffraction losses on the data. You get what you pay for and I found Sysconcept to be flawless after 1.5years of use.
 
Dec 11, 2017 at 5:39 PM Post #34,746 of 42,758
Besides all of the measurements, I think it would be great if, at the next Head-Fi show, they'd get a panel of 20 people to blind test DACs and amps and post the results ... 3 different groups on 3 different days would be even better.

* Does any DAC/amp consistently get identified? ie., 70% of panelists correctly identified the Mojo
* Does any DAC/amp consistently get voted best? worst?
* Does any DAC/amp consistently get tagged with a sound signature? i.e., relaxed, detailed, wide sound stage, etc

Now THAT would be some killer data!

But most vendors would be terrified of such a study and likely wouldn't actively participate or sponsor it ... which should tell us all something.
I blind tested Mojo several times and didn't get it. Bought one on a month's trial and never looked back. I came to the conclusion that s blind test tested the tester as well as the equipment. Could I immediately identify micro details? No. Have I been happy listening to the Mojo and disappointed when listening directly to my phone? Yes.
 
Dec 11, 2017 at 6:09 PM Post #34,747 of 42,758
(Sorry, but I can't remember the qualities that people say get enhanced with optical. Probably though, just better overall. I would love to hear Mojo at it's absolute best.

The differences may come down to optical sounding warmer/smoother than USB or coaxial. This is because with a USB or coaxial connection the potential for noise electrically entering the system would pump the noise floor up and down, which in turn creates a brightness/hardness to the sound. This may come off as more detail initially, but Rob has maintained it’s a false sense of detail that reduces nuance and I can see the reasoning. YMMV. In the end choose what you prefer.

I say optical may sound smoother/warmer because not all USB implementations/sources are crap and a relatively clean laptop on battery power may produce the same sound as optical. Jitter has been shown by Rob to not be an issue (his explanations are posted many, many times throughout the various Chord DAC threads on how he’s solved the jitter issue with S/PDiF) and the differences between inputs mostly comes down to filtering electrical noise, which optical is immune by nature of it’s light transmission.

These recent posts may help those that are curious about Rob’s jitter implementations:

https://www.head-fi.org/threads/cho...official-thread.831345/page-621#post-13904762

https://www.head-fi.org/threads/cho...official-thread.831345/page-621#post-13904808

One can also search the site for Jitter by Rob Watts:

https://www.head-fi.org/search/4313159/?q=Jitter&o=relevance&c[user][0]=394072&c[p][sonnb_xengallery_photo][focal]=0&c[p][sonnb_xengallery_photo][iso]=0&c[p][sonnb_xengallery_photo][aperture]=0
 
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Dec 11, 2017 at 7:46 PM Post #34,750 of 42,758
The differences may come down to optical sounding warmer/smoother than USB or coaxial. This is because with a USB or coaxial connection the potential for noise electrically entering the system would pump the noise floor up and down, which in turn creates a brightness/hardness to the sound. This may come off as more detail initially, but Rob has maintained it’s a false sense of detail that reduces nuance and I can see the reasoning. YMMV. In the end choose what you prefer.

I say optical may sound smoother/warmer because not all USB implementations/sources are crap and a relatively clean laptop on battery power may produce the same sound as optical. Jitter has been shown by Rob to not be an issue (his explanations are posted many, many times throughout the various Chord DAC threads on how he’s solved the jitter issue with S/PDiF) and the differences between inputs mostly comes down to filtering electrical noise, which optical is immune by nature of it’s light transmission.
Optical is just a way to cut the wire distance between two devices, but devices themselves can still be full of noise. My question is, does all optical sources sound the same for Chord DACs ? The transceiver that send light to the cable is powered by current which can be dirty. It's not like the signal is created from nothing.
I wish I will understand such things as, what if the signal is already dirty, how the DAC knows how to get the good data from it ?
I assume not all optical sources uses same clock and also I don't think Mojo can understand every variation of clocks that are out there
For example a Focusrite Rednet 3 can improve the sound on Mojo ? If so, how and why?

I understand that jitter is not measurable, but measurements are USELESS.
Audio cables, power cables etc make a difference, but measurements show nothing. Same with DACs, AMPs etc.
 
Dec 11, 2017 at 9:24 PM Post #34,751 of 42,758
Optical is just a way to cut the wire distance between two devices, but devices themselves can still be full of noise. My question is, does all optical sources sound the same for Chord DACs ? The transceiver that send light to the cable is powered by current which can be dirty. It's not like the signal is created from nothing.
I wish I will understand such things as, what if the signal is already dirty, how the DAC knows how to get the good data from it ?
I assume not all optical sources uses same clock and also I don't think Mojo can understand every variation of clocks that are out there
For example a Focusrite Rednet 3 can improve the sound on Mojo ? If so, how and why?

I understand that jitter is not measurable, but measurements are USELESS.
Audio cables, power cables etc make a difference, but measurements show nothing. Same with DACs, AMPs etc.

I said electrical noise. Optical transmits data through pulses of light and can not carry electrical noise and would essentially filter it out. I’m not saying the signal can’t be degraded in other ways before it’s sent over the optical cable.

As for differences between optical sources I do find that different optical sources can have different sound. I purchased an AK100 mk2 to specifically pair with the Mojo given its form factor and dual mSD slots, but when comparing the optical output of the AK100 mk2 to the AK240 I found that the AK100 mk2 sounded etched, harsh, and smeared. Was this jitter or something else? I asked on this forum and the reply was that the AK100mk2 might have some DSP on but it didn’t, at least from a user standpoint. My only conclusion is that the optical transmitter of the AK100 mk2 was inferior to the AK240 using the same cable but I’m not versed enough on the matter to know exactly why/how. Perhaps, as you say, the signal is simply messed up before being output through optical and therefore the Mojo couldn’t recover what it thinks is correct(?). All I know is that jitter itself seems to not be an issue based on what information has been provided by the designer, but that’s not to say there won’t be other issues with optical.

The original question was what to expect sonically from optical vs USB so I replied that (a decently implemented) optical may be smoother/warmer based on my experience and also based on what has been shared by the designer. This is the typical difference with optical vs a dirty USB source. As for improvements from a $1000 device like the Focusrite Rednet 3 it would be helpful to know what ‘improvement’ means if measurements are not meaningful. Do you have any sonic impressions on the Focusrite Rednet 3 in the chain and without?
 
Dec 12, 2017 at 7:54 AM Post #34,752 of 42,758
I don't have Focusrite Rednet 3 but many users suggest that it will improve dramatically DACs that suffer from jitter on spdif because of its revolutionary master clock. All I can see on Chord based forums is that "jitter is not a problem" but my question is why different optical sources sound different on Chord DACs ? I don't know if Hugo 2 is better at this against Mojo.
It's gonna be awesome if someone can answer.

Yes, optical sounds smoother and warmer on my Mojo/Hugo 2. On Hugo 2, I never used USB because on Mojo going from filtered USB to optical with a cheap cable was a clear improvement. Hugo 2 doesn't sound bright/brittle like some people said.
 
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Dec 13, 2017 at 4:21 PM Post #34,753 of 42,758
Compliments to the Mojo.

After upgrading my moderately priced desktop active speakers to an amplifier and speakers of better quality, the Mojo rocks more.

There's more spacing, and separation. Lyrics are easier to hear. These are all more qualities down to the improvement in amp and speakers though. However it lays out just how good the Mojo actually is. I had been missing quite a lot.

My speakers are excellent for low volume listening (as is the amplifier), so patently perfect for the job. The speakers need space behind for the bass port, and I have managed to give them 30cm. Supposedly they need to have 50cm ideally for tonal balance, but I am missing nothing. Sometimes they feel a touch bass heavy, sometimes a touch bass light so they must be spot on.


Anyway back to the Mojo. What it does with well recorded music is beyond question. The tonality and detail, deliver some rather incredible results.

I think my point of this post though, is more about what the Mojo does with lesser quality recordings. My albums which stand out for this are my CD FLAC rips of two Shirley Bassey albums that I have. 'Never, never, Never', and 'Good, Bad, but Beautiful'. While I would not have thought of her music production to be lacking. There is discrepancy with these two older albums from the 1970s. The Mojo doesn't make them sound bad though. It just makes them sound wonderful, and paired with my new desktop audio kit, they sound good. (The tone in Dame Shirley Bassey's voice is superb, and she's perfectly relaxing to listen to. Don't just think high power Goldfinger etc. She records some lovely stuff, like Send in the Clowns, or No Regrets.)

You read about kit that makes poorer recording sound bad, however I can easily conclude that the Mojo doesn't. If your poorer recordings are sounding at all bad or harsh. You need to look at your other kit and not the Mojo.

Old desktop active speakers: Q Acoustics BT3, Chord Clearway speaker cable to connect satellite speaker, QED Reference Audio jack-to-phono cable.
New desktop equipment (two weeks old): Rega Brio 2017, Dynaudio Emit M10, Chord Clearway speaker cable, QED Reference Audio jack-to-phono cable.
 
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Dec 13, 2017 at 5:03 PM Post #34,754 of 42,758
I got in contact with Chord about the Mojo I bought a few months ago.

They told me to send it to a repair shop.

LMAO **** that. Wow.
 

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