Chord Mojo(1) DAC-amp ☆★►FAQ in 3rd post!◄★☆
Jul 5, 2016 at 12:37 AM Post #19,520 of 42,765
 
My Mojo landed on Friday.
 
I've read all of info here and I'd like to say thanks to all of you.
 
However there are a couple of questions bouncing in my head, though. Let's limit to the PCM realm.
 
1)Assuming that I've a recording that has some TPL over 0, will Mojo address this issue as well?
 
2)Will Mojo's filters take care of the spurious frequencies that I nearly always find even in Master Quality recordings?
 
Thanks in advance

 
I think Slaphead's answer pretty much covered it; if its on the recording, then Mojo can't do anything about it.
 
Just to reinforce; if it is clipped at true 0 dBFS (max level) then Mojo can't do anything about it.
 
As to spurious frequencies - if it is below 24 kHz (for 48) then Mojo will not do anything about it; but for outputs above 24 kHz then Mojo will do an exceptional job of eliminating those errors; this is to ensure correct reconstruction of the timing of transients (there is much more to transient timing recovery than simply eliminating the out of band aliasing). You can see Mojo's filter performance with a 48 kHz 0 dBFS random noise input from this measurement:
 

 
You can see no spurious output above 24.25 kHz at all; (the -160 dB noise floor is actually the AP ADC). I am not aware of any other non Chord DAC at any price coming even close to this performance. The reason why this is important is that the aliasing images themselves degrade transient timing, as they affect the timing of when a transient crosses through zero. Now with sampling these images extend to infinite frequencies, so this is one reason why I digitally filter to 2048 FS (not the usual 8 or 16 FS).
 
Rob
 
Jul 5, 2016 at 1:48 AM Post #19,521 of 42,765
anyone tried - Strive by amber rubarth?
 
sennheiser used this song for their guest to test HE-1 headphone, whole album is actually pretty good.
 
 
second song- somewhere,somebody by jennifer warnes
third song - money for nothing by dire straits.
 
Jul 5, 2016 at 4:06 AM Post #19,524 of 42,765
Jul 5, 2016 at 5:40 AM Post #19,525 of 42,765
  For those using iphone with Mojo, one of the most costs effective way is using cheap silicon bands meant for bicycles.   
L3000.gif

 

 
I have been to about eight bike shops with this photo and perused Amazon for this specific silicone band. No luck. This looks to be the perfect thing for my intentions. Where did you get this?!? Or, does it have a brand and product name I can search for?
 
Jul 5, 2016 at 5:55 AM Post #19,526 of 42,765
   
I have been to about eight bike shops with this photo and perused Amazon for this specific silicone band. No luck. This looks to be the perfect thing for my intentions. Where did you get this?!? Or, does it have a brand and product name I can search for?

Did you buy yourself a bike or a dog while you were there?
blink.gif

 

 
Jul 5, 2016 at 6:13 AM Post #19,528 of 42,765
   
I think Slaphead's answer pretty much covered it; if its on the recording, then Mojo can't do anything about it.
 
Just to reinforce; if it is clipped at true 0 dBFS (max level) then Mojo can't do anything about it.
 
As to spurious frequencies - if it is below 24 kHz (for 48) then Mojo will not do anything about it; but for outputs above 24 kHz then Mojo will do an exceptional job of eliminating those errors; this is to ensure correct reconstruction of the timing of transients (there is much more to transient timing recovery than simply eliminating the out of band aliasing). You can see Mojo's filter performance with a 48 kHz 0 dBFS random noise input from this measurement:
 

 
You can see no spurious output above 24.25 kHz at all; (the -160 dB noise floor is actually the AP ADC). I am not aware of any other non Chord DAC at any price coming even close to this performance. The reason why this is important is that the aliasing images themselves degrade transient timing, as they affect the timing of when a transient crosses through zero. Now with sampling these images extend to infinite frequencies, so this is one reason why I digitally filter to 2048 FS (not the usual 8 or 16 FS).
 
Rob


Thanks Rob, this is quite a read. I actually enjoy Mojo a lot.
 
My asset will then be to leave original recordings untouched, unless I'll spot TPL exceeding specs.
DSD wise, being myself mostly on the go and using my iPhone 6+ as host, I'll cross-compare i.e. DSD256 original albums vs FLAC352/32 obtained by means of AUL Converter 48x44, which it is a great offline converter.
 
Thanks again
 
Jul 5, 2016 at 6:19 AM Post #19,529 of 42,765
   
I have been to about eight bike shops with this photo and perused Amazon for this specific silicone band. No luck. This looks to be the perfect thing for my intentions. Where did you get this?!? Or, does it have a brand and product name I can search for?

I think this is it:
https://www.amazon.com/ChineOn-Cycling-Bicycle-Silicone-Flashlight/dp/B00CBT76TG

 

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