Chord Mojo(1) DAC-amp ☆★►FAQ in 3rd post!◄★☆
Feb 21, 2020 at 7:04 PM Post #39,887 of 42,765
Hi everybody,

just got a Rasberry Pi 4 that I will use with Ropieee (Roon client) and Chord Mojo via USB.

I wonder: I should use the USB 2.0 or USB 3.0? I think that Mojo is limited to 2.0 but also I think that in the past I read that is always better for audio 2.0 instead that 3.0.

What do you think and use?

It looks like USB 2.0, with a data rate of 480Mbps, should be able to easily handle any standard digital audio signal, according to this list of data rates -
Quoted from - http://archimago.blogspot.com/2016/05/measurements-music-servers-possibly.html
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I mentioned above that 50Mbits/s is rather extreme for audio... Realize that for uncompressed stereo 16/44 PCM we just need about 1.4Mbps, for stereo 24/96 it goes up to 4.6Mbps, for stereo 24/192 it's 9.2Mbps, for stereo 32/384 it's 24.6Mbps, and crazy extreme stereo 32/768 it's 49.2Mbps. As for the DSD side, stereo DSD64 is 5.6Mbps, DSD128 goes up to 11.2Mbps, DSD256 is 22.4Mbps, and DSD512 goes to a whopping 44.8Mbps.
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Feb 22, 2020 at 11:05 AM Post #39,888 of 42,765
Does it make sense to use the Mojo (or, in my case, Mojo + Poly) with powered noise-cancelling headphones (in my case, Sony WH-1000XM3)? Or is streaming Tidal/Spotify from iPhone (via Poly) to Mojo, and then from Mojo to powered headphones pointless because headphone amp/dac trumps the Mojo (in which case I might as well just go wireless from iPhone directly to headphones)? Or is that a headphone-specific question, in that some respond differently from others to having an input plugged in, vs receiving input wirelessly?

(Sorry if previously asked and answered - I tried to search thread but didn't see answer to my Q.)
 
Feb 22, 2020 at 11:12 AM Post #39,889 of 42,765
Does it make sense to use the Mojo (or, in my case, Mojo + Poly) with powered noise-cancelling headphones (in my case, Sony WH-1000XM3)? Or is streaming Tidal/Spotify from iPhone (via Poly) to Mojo, and then from Mojo to powered headphones pointless because headphone amp/dac trumps the Mojo (in which case I might as well just go wireless from iPhone directly to headphones)? Or is that a headphone-specific question, in that some respond differently from others to having an input plugged in, vs receiving input wirelessly?

(Sorry if previously asked and answered - I tried to search thread but didn't see answer to my Q.)

If your headphone is wireless, then it has its own dac and amp built in, so that is what you will be hearing. I would expect no difference using Poly vs streaming directly from your phone.
 
Feb 22, 2020 at 11:30 AM Post #39,890 of 42,765
If your headphone is wireless, then it has its own dac and amp built in, so that is what you will be hearing. I would expect no difference using Poly vs streaming directly from your phone.
To clarify - the Sony WH-1000XM3 can be wireless (e.g., streaming directly from iPhone to headphones), but can also be used wired (stream iPhone to Mojo via Poly, then wired from Mojo to headphones). Are you saying that it is useless to use the Mojo with any powered / noise-cancelling headphone?
 
Feb 22, 2020 at 11:43 AM Post #39,891 of 42,765
To clarify - the Sony WH-1000XM3 can be wireless (e.g., streaming directly from iPhone to headphones), but can also be used wired (stream iPhone to Mojo via Poly, then wired from Mojo to headphones). Are you saying that it is useless to use the Mojo with any powered / noise-cancelling headphone?

If you use them wired, it would depend on what the specific headphone is doing. If there is a mode where the headphone becomes just a passive headphone (probably also powered off) then you would be hearing all the benefits of Mojo. But if that isn’t the case, and the headphone is taking the wired signal and doing an A-to-D conversion, then processing it, then DAC and amp functions, there would likely be no benefit. So depends on how the specific headphone.
 
Feb 22, 2020 at 12:18 PM Post #39,892 of 42,765
If you use them wired, it would depend on what the specific headphone is doing. If there is a mode where the headphone becomes just a passive headphone (probably also powered off) then you would be hearing all the benefits of Mojo. But if that isn’t the case, and the headphone is taking the wired signal and doing an A-to-D conversion, then processing it, then DAC and amp functions, there would likely be no benefit. So depends on how the specific headphone.
That's what I suspected. I really like using the Sonys with noise cancelling powered on when out and about (esp subway) and when travelling (trains/airplanes) vs my other on-ears (M&D MH40s) or earbuds (Shure wired; Jabra wireless) and ideally would like to get benefit of both that AND Chord mojo. Guess really a tech question for Sony then though.

Thanks for your input (ick, sorry, no pun intended).
 
Feb 22, 2020 at 1:32 PM Post #39,893 of 42,765
Does it make sense to use the Mojo (or, in my case, Mojo + Poly) with powered noise-cancelling headphones (in my case, Sony WH-1000XM3)? Or is streaming Tidal/Spotify from iPhone (via Poly) to Mojo, and then from Mojo to powered headphones pointless because headphone amp/dac trumps the Mojo (in which case I might as well just go wireless from iPhone directly to headphones)? Or is that a headphone-specific question, in that some respond differently from others to having an input plugged in, vs receiving input wirelessly?

(Sorry if previously asked and answered - I tried to search thread but didn't see answer to my Q.)

It will sound much better.

Just think about it.
- Sony WH-1000XM3 gets 30 hours of battery life
- Chord Poly + Mojo only gets 8 hours

So you know Sony cut a lot of corners to squeeze out that 30 hours of battery life.

Sony WH-1000XM3 + Poly / Mojo = basshead headphone with much better clarity and details (over Bluetooth it is a very muddy and unclear headphone)
Bose NC 700 + Poly / Mojo = neutral headphone similar to like a HD 650.

However you have to use the Sony and Bose headphone powered on with the Poly / Mojo because they are tuned with the onboard DSP.

Without the DSP enabled, both the Sony and Bose just sound really bad (Sony and Bose did not bother tuning the driver, they fixed it with an active EQ)
 
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Feb 22, 2020 at 2:35 PM Post #39,894 of 42,765
It will sound much better.

Just think about it.
- Sony WH-1000XM3 gets 30 hours of battery life
- Chord Poly + Mojo only gets 8 hours

So you know Sony cut a lot of corners to squeeze out that 30 hours of battery life.

Sony WH-1000XM3 + Poly / Mojo = basshead headphone with much better clarity and details (over Bluetooth it is a very muddy and unclear headphone)
Bose NC 700 + Poly / Mojo = neutral headphone similar to like a HD 650.

However you have to use the Sony and Bose headphone powered on with the Poly / Mojo because they are tuned with the onboard DSP.

Without the DSP enabled, both the Sony and Bose just sound really bad (Sony and Bose did not bother tuning the driver, they fixed it with an active EQ)

I think Sony XM3 sounds perfect over LDAC Bluetooth. And it driving it by an amp doesn't make a big difference.

It is essential to reduce its bass by EQ. EQ makes a hell of difference. Reduce 62 dB by -2 dB and 125 dB by -4 dB, remove the rest fine. Now you have an awesome sounding Bluetooth headphone.
 
Feb 22, 2020 at 2:54 PM Post #39,895 of 42,765
When the Bose NC 700 with a neutral bass hits harder than the Sony WH-1000XM3 (which has a huge bass boost), then you know that the internal amplifier inside the WH-1000XM3 is too weak.

With an external amplifier like the Poly + Mojo, the bass slams super hard and can even shake your head like it should given the boosted bass it has.

To me, this is all the proof that Sony put an amplifier inside the WH-1000XM3 that is too weak which using more bits and kHz cannot solve from LDAC.
 
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Feb 22, 2020 at 2:58 PM Post #39,896 of 42,765
But I use both headphones in planes without the Poly + Mojo ofcourse as sound quality is not a priority under those conditions :p
 
Feb 22, 2020 at 3:46 PM Post #39,897 of 42,765
That's what I suspected. I really like using the Sonys with noise cancelling powered on when out and about (esp subway) and when travelling (trains/airplanes) vs my other on-ears (M&D MH40s) or earbuds (Shure wired; Jabra wireless) and ideally would like to get benefit of both that AND Chord mojo. Guess really a tech question for Sony then though.

Thanks for your input (ick, sorry, no pun intended).
I think that you are doing the right thing by identifying your needs for your different use cases.
Some posters fall into the trap (maybe because of limits on budget) of trying to identifying one system to cover all their use cases.
In reality the best system for casual or desktop listening at home, could differ to the best system for commuting on public transport.
If you need to use during your commute, noise cancelling iems or headphones that convert the mojo analog output back to digital, then perform dsp, then convert back to analog to the iems/headphones, then you are wasting the mojo sound quality.
 
Feb 23, 2020 at 6:34 AM Post #39,898 of 42,765
I have a really noob question. Which cable do i need if i wanna plug my Fiio M11 as source in the Chord Mojo and is it quality wise worse than usb connection to Mojo? I know that i have to turn Fiio in Spdif out and it works via the coax connection on the Mojo but i don't know which cable to buy if i want just one cable. At the moment i use two cables plugged together but don't know the connectors names since i don't really know the difference between coax, aux and spdif it all looks so similar.
 
Feb 23, 2020 at 6:49 AM Post #39,899 of 42,765
I have a really noob question. Which cable do i need if i wanna plug my Fiio M11 as source in the Chord Mojo and is it quality wise worse than usb connection to Mojo? I know that i have to turn Fiio in Spdif out and it works via the coax connection on the Mojo but i don't know which cable to buy if i want just one cable. At the moment i use two cables plugged together but don't know the connectors names since i don't really know the difference between coax, aux and spdif it all looks so similar.
You need an USB-C to Micro-USB OTG cable. I am using one by Meenova to connect the M11 and the Mojo.
 
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