Chord Mojo(1) DAC-amp ☆★►FAQ in 3rd post!◄★☆
May 16, 2016 at 8:17 AM Post #17,671 of 42,759
May 16, 2016 at 8:19 AM Post #17,672 of 42,759
  I don't think that it is an issue with the Mojo. There are quite a few posts on this thread relating to hiss, and there seem to be two main causes:
 
1 - Some people still have excellent hearing, enabling them still to hear low levels of hiss
2 - The more sensitive phones (like Puga74s, and the SE846 rated at 9 ohms) are able to detect the very low levels of hiss - the less sensitive phones cannot detect such low levels of hiss (but inevitably their higher impedances make them harder to drive). It seems like a bit of a trade-off, sensitivity and ease to drive v detectable level of hiss

 
I have the A12's which have the same impedance, no hiss for me.  Personally, I think hiss has more to do with people's ears for the most part except in cases where it's well documented with specific ciem's like the zeus.
 
May 16, 2016 at 8:20 AM Post #17,673 of 42,759
Ah. You do seem a bit enthusiastic about it.... :wink_face:

With that, signing off!


Well just allow a little joy in my life , will you? :wink:
 
May 16, 2016 at 8:22 AM Post #17,674 of 42,759
 
Ah. You do seem a bit enthusiastic about it....
wink_face.gif


With that, signing off!


Well just allow a little joy in my life , will you?
wink.gif

 
OK, OK; just as long as it's 'Mobile Joy'...
 
May 16, 2016 at 8:23 AM Post #17,675 of 42,759
That took long
smily_headphones1.gif
...
Yeah, well, you know, that's just, like, your opinion, man.
This is a very complicated case, Maude. You know, a lotta ins, lotta outs, lotta what-have-you's
biggrin.gif

Well but seriously for me the changes are very real and audible to anyone with proper hearing... You know, that's just my opinion...
Did you make comparisons yourself or is your opinion based on block knowledge?
Doesn't mean to come of rude, it's just that sometimes things you thought you know are true, because a overwhelming majority believes they are, turn out to be false after all...
Audio transport via USB is a handshake live stream thingies... So timing is important there, I think I know someone who could tell a thing or two about the importance of timing...
Now I am done.
Cheers

 
Lol, I happen to also agree, from my own experience even digital cables can affect the sound, IMO.
 
Cable debates always seem to have the same outcome! 
 
P.S. Perhaps it is best that we leave all the drooling to your pets. 
 

 
May 16, 2016 at 9:14 AM Post #17,676 of 42,759
   
Lol, I happen to also agree, from my own experience even digital cables can affect the sound, IMO.
 
Cable debates always seem to have the same outcome! 
 
P.S. Perhaps it is best that we leave all the drooling to your pets. 
 

 
Okay - you convinced me personally to give the influence of digital interconnects a try.
What would be the perfect OTG cable in terms of sound improvement to connect a android phone to mojo?
oxygenfree, silver, gold, shielded?
 
May 16, 2016 at 9:20 AM Post #17,677 of 42,759
   
Okay - you convinced me personally to give the influence of digital interconnects a try.
What would be the perfect OTG cable in terms of sound improvement to connect a android phone to mojo?
oxygenfree, silver, gold, shielded?

 
 
Above all other considerations, the most important, for use between an Android phone and Mojo, would be shielded.
 
Ferrite chokes can also be helpful in minimising the potential influence of RF.
 
May 16, 2016 at 9:48 AM Post #17,680 of 42,759
Here's my change to my audio_policy.conf file:
 
      usb_device {
        sampling_rates 44100|48000
        channel_masks AUDIO_CHANNEL_OUT_STEREO
        formats AUDIO_FORMAT_PCM|AUDIO_FORMAT_MP3|AUDIO_FORMAT_AAC
        devices AUDIO_DEVICE_OUT_USB_DEVICE
      }
 
This is on a asus zenfone laser running cyanogenmod 13.
With this change when I use google play or youtube etc, I get 48000 going to my mojo (according to the light color).
It looks like android will still up sample to the highest rate provided here.
 
To me, I don't really hear a difference, and I can't say what android is doing internally, it could be up sampling then down sampling for all I know :wink:
 
May 16, 2016 at 11:00 AM Post #17,683 of 42,759
   
Puga, I do not own a an E-Q8, but my 64-Audio A10 IEM has an impedance of 18 Ohm and a sensitivity of 117 dB and I can hear a hiss through Mojo. So, the chances are, the E-Q8 does have a hiss because its impedance is rated at 12 Ohm. Unless the sensitivity of the E-Q8 is far less than 110 dB (couldn't find the exact sensitivity rating of E-Q8), I don't think your Mojo is a faulty unit..

 
Thanks for the inputs. I was about to return my chord mojo (its already packed) but based on your explanation, I am not returning it anymore. The best thing for me I guess is to look for iems that has similar sound signature as my e-q8 but with higher impedance. I am eyeing the grado gr10e as its impedance is 32 ohms. I think that would work for my setup.
 
May 16, 2016 at 11:15 AM Post #17,684 of 42,759
  I don't think that it is an issue with the Mojo. There are quite a few posts on this thread relating to hiss, and there seem to be two main causes:
 
1 - Some people still have excellent hearing, enabling them still to hear low levels of hiss
2 - The more sensitive phones (like Puga74s, and the SE846 rated at 9 ohms) are able to detect the very low levels of hiss - the less sensitive phones cannot detect such low levels of hiss (but inevitably their higher impedances make them harder to drive). It seems like a bit of a trade-off, sensitivity and ease to drive v detectable level of hiss

 
Thanks for the explanation. I'm a bit sensitive to this hissing but given the setup I have, I cannot do anything about it unless I buy another iem with higher impedance and less sensitivity. This a journey, an expensive journey :). But it makes us happy :)
 
May 16, 2016 at 11:31 AM Post #17,685 of 42,759
Thanks for the explanation. I'm a bit sensitive to this hissing but given the setup I have, I cannot do anything about it unless I buy another iem with higher impedance and less sensitivity. This a journey, an expensive journey :). But it makes us happy :)


You could also consider adding an impedance adapter. I myself have not tried it. But I hear it helps sometimes. Keep in mind though, it could potentially change the frequency response of your IEM.
 

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