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Chord Mojo(1) DAC-amp ☆★►FAQ in 3rd post!◄★☆
Jul 27, 2018 at 9:42 AM Post #36,946 of 42,765
Can someone confirm thats Deezer on Android is not working with the Mojo? Or is there a solution?
 
Jul 27, 2018 at 10:49 AM Post #36,948 of 42,765
Galaxy S9 (Android 8) via OTG Cable. UAPP works fine. Deezer only Silence.
 
Jul 27, 2018 at 10:59 AM Post #36,949 of 42,765
sg2k said:
Galaxy S9 (Android 8) via OTG Cable. UAPP works fine. Deezer only Silence.
Click to expand...
OK, then you have an issue with your phone not sending the data to Mojo.
I think it is a well known UAPP issue, in that it is set up in 'exclusive' mode, and will not let other apps transmit to Mojo, whilst UAPP is still open in the background.
I suspect the details are in the FAQ in post #3, but I will search as well.
In the short term, try closing UAPP, and then see if Deezer works ok.
 
Jul 27, 2018 at 11:09 AM Post #36,950 of 42,765
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Jul 28, 2018 at 2:40 AM Post #36,951 of 42,765
So Mojo has 26000 taps? The same amount as Hugo? What is a tap? If most of the older dacs had 4 (4 units or 4 thousands?) of them, how much the newer ones have? F. E. Sony portable dacs, that some say play better then Mojo. Of corse I undertstand that Chord uses custom chips and scalable decoding algorithm that focuses on catching the timing of notes, but how exactly does tapping more times help the sound sound more natural? That it guesses more correctly timestamp of each note? Did the competition found their own way to sound as good without so much focus on timing or did they simply start to focus on timing as well without calling it "taps"?
 
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Jul 28, 2018 at 4:06 AM Post #36,952 of 42,765
miketlse said:
I think it is a well known UAPP issue, in that it is set up in 'exclusive' mode, and will not let other apps transmit to Mojo, whilst UAPP is still open in the background.
Click to expand...

That is the solution. I had UAPP on "always open UAPP when connected to USB Device" What i did was i deleted UAPP and installed it again. Now I checked the option "Ask always" and Deezer works. Thank you!
 
Jul 28, 2018 at 4:35 AM Post #36,953 of 42,765
myusernameislove said:
So Mojo has 26000 taps? The same amount as Hugo? What is a tap? If most of the older dacs had 4 (4 units or 4 thousands?) of them, how much the newer ones have? F. E. Sony portable dacs, that some say play better then Mojo. Of corse I undertstand that Chord uses custom chips and scalable decoding algorithm that focuses on catching the timing of notes, but how exactly does tapping more times help the sound sound more natural? That it guesses more correctly timestamp of each note? Did the competition found their own way to sound as good without so much focus on timing or did they simply start to focus on timing as well without calling it "taps"?
Click to expand...

A tap is the basic building block of an FIR filter; its a multiplier, and a coefficient, and this taps into the audio data that is stored into memory. So one tap is one multiply and accumulate; the more taps you have, the more accurate the reconstruction is; and by reconstruction we are trying to recover the original analogue signal before it is sampled. This is important, because all other DAC's do a poor job of reconstruction, and have big timing errors for transients - and transients are used by the brain to create the perception of pitch (particularly bass), timbre, soundstage and of course tempo and the starting and stopping of notes.

In the case of my WTA filter, as you double the number of taps, you double the accuracy of the reconstruction - for Mojo, it is better than 12 bit accurate in reconstruction under all circumstances - conventional filters have under certain circumstances peak errors that only make them 2 or 3 bit accurate.

This problem can only be solved by lots of processing - there are no short cuts, no easy way to do this, only by lots of taps and a filter algorithm that is close to the ideal sinc function (which recovers a bandwidth limited signal perfectly) like my WTA filter.

I spent 14 years of my career as a consultant designing audio devices for major silicon companies - and it's impossible to get the performance that Mojo manages, both in measured abilities, and musicality. If "some say play better than Mojo" then they either have another agenda, or actually like distorted poor resolution music...
 
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Jul 28, 2018 at 4:52 AM Post #36,954 of 42,765
Rob Watts said:
A tap is the basic building block of an FIR filter; its a multiplier, and a coefficient, and this taps into the audio data that is stored into memory. So one tap is one multiply and accumulate; the more taps you have, the more accurate the reconstruction is; and by reconstruction we are trying to recover the original analogue signal before it is sampled. This is important, because all other DAC's do a poor job of reconstruction, and have big timing errors for transients - and transients are used by the brain to create the perception of pitch (particularly bass), timbre, soundstage and of course tempo and the starting and stopping of notes.

In the case of my WTA filter, as you double the number of taps, you double the accuracy of the reconstruction - for Mojo, it is better than 12 bit accurate in reconstruction under all circumstances - conventional filters have under certain circumstances peak errors that only make them 2 or 3 bit accurate.

This problem can only be solved by lots of processing - there are no short cuts, no easy way to do this, only by lots of taps and a filter algorithm that is close to the ideal sinc function (which recovers a bandwidth limited signal perfectly) like my WTA filter.

I spent 14 years of my career as a consultant designing audio devices for major silicon companies - and it's impossible to get the performance that Mojo manages, both in measured abilities, and musicality. If "some say play better than Mojo" then they either have another agenda, or actually like distorted poor resolution music...
Click to expand...

I really like your technical design and execution of the Mojo DAC - I just wish I liked the physical design... :wink: :thinking:
 
Jul 28, 2018 at 10:32 AM Post #36,958 of 42,765
upload_2018-7-28_15-31-44.jpeg


Here is my bundle of fun. The Zee Audio cable is brilliant and a bargain. Mind you I have not updated the IOS since 11.2.6 as I don't want to risk the cable being rejected by Apple. As the phone is an old 5S used purely for Tidal there is no need. I made the plate between the phone and the Mojo to protect the connectors as I had a previous one break.
 
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Jul 28, 2018 at 10:40 AM Post #36,959 of 42,765
I really love my Mojo, it only falls flat when facing something like the iFi Pro iDSD, but that’s almost 5 times the price.

I think the only thing bugging me is the amp section being a little underpowered for planars.
 
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Jul 28, 2018 at 2:12 PM Post #36,960 of 42,765
Rob Watts said:
A tap is the basic building block of an FIR filter; its a multiplier, and a coefficient, and this taps into the audio data that is stored into memory. So one tap is one multiply and accumulate; the more taps you have, the more accurate the reconstruction is; and by reconstruction we are trying to recover the original analogue signal before it is sampled. This is important, because all other DAC's do a poor job of reconstruction, and have big timing errors for transients - and transients are used by the brain to create the perception of pitch (particularly bass), timbre, soundstage and of course tempo and the starting and stopping of notes.

In the case of my WTA filter, as you double the number of taps, you double the accuracy of the reconstruction - for Mojo, it is better than 12 bit accurate in reconstruction under all circumstances - conventional filters have under certain circumstances peak errors that only make them 2 or 3 bit accurate.

This problem can only be solved by lots of processing - there are no short cuts, no easy way to do this, only by lots of taps and a filter algorithm that is close to the ideal sinc function (which recovers a bandwidth limited signal perfectly) like my WTA filter.

I spent 14 years of my career as a consultant designing audio devices for major silicon companies - and it's impossible to get the performance that Mojo manages, both in measured abilities, and musicality. If "some say play better than Mojo" then they either have another agenda, or actually like distorted poor resolution music...
Click to expand...

Thank you. I am not saying I do understand it all. But I understand the concept of scalability, as I work for a database company that relies on this scalability as well. I did not expect detailed response, yet I received it. Be well. It is summer. Spend it somewhere with loved ones and or near water.. :)
 
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