VoCore Forum

I made a PCM2704 Sound Card for AirPlay Server with VoCore

Good thing: it works, AirPlay works too..
Bad thing: when i enjoy music, i hear noise too..

It seems noise begins by the time WiFi is on
i try wget some files ( heavy WiFi transition) noise get worse, When i turn off WiFi, noise gone too..

Need to be fixed..

Case size missed 0.5mm each side, can't fit but this is nothing, easy to fix~

A cap could work?

Hey, that's pretty awesome

Sounds like just some interference.. I think some shielding or an antenna replacement would help. Analog sound is prone to interference.. a good example is, my desktop speakers.. they pick up radio stations.. so I leave them off.

This really looks like some very slick and useful device! Great work! I'm sure you will figure out the noise thing, can't really suggest anything apart from trying to shield random parts, or trying thicker traces on the pcb and/or having them greater distance apart. Perhaps a ground fill would help too...

It is easy to fix, just make the memory buffer bigger, make it to 1MB or 2MB, it might delay 2~3 seconds to play, but will avoid noise from unstable wwan.
VoCore is not optimized for mass data transfer due to its small size, so software part buffer is necessary.

Vonger wrote:It is easy to fix, just make the memory buffer bigger, make it to 1MB or 2MB, it might delay 2~3 seconds to play, but will avoid noise from unstable wwan.
VoCore is not optimized for mass data transfer due to its small size, so software part buffer is necessary.

Sadly, it's a hardware issue, i think this kind of ground noise is current noise because of electromagnet interference or something like that.

1, I used a well-made USB PCM2704 Sound Card with no this kind noise at all. (i try wired my card long-distance from vocore no luck )
2, Noise began at snd drivers recognition, getting worse when WiFi being initiation, before any music(or sound) played yet.
3, Try madplay some mp3 file with noise too( not worth to try because point 2)

So it's clearly not a soft issue by driver( See point 1) or Shairplay software ( See Point 2 and 3)

Still working on it.

update:

noise is due to wifi has been confirmed

when PCM2704 is near RT5350 about 40-50mm , noise began..
moving away , noise gone, moving closer, noise getting worse..
turn off WiFi, noise gone, turn on WiFi, noise back..

i have no idea how to fix this

Endat wrote:I think some shielding or an antenna replacement would help.

^ maybe remove blue onboard antenna, and use external antenna like on VoCore 0.5

...Or you could redesign it so it could be mounted with the antenna/cpu facing OUT