Audio noise when no playback with Cubieboard2 (A20)

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Audio noise when no playback with Cubieboard2 (A20)

Postby uxalarm » Thu Jun 09, 2016 6:04 pm

After my later adventures with getting sound out of the jack with the Cubieboard 2, I thought I fixed the main audio issue, but I've hit another one: there is very annoying buzzing sound that comes out after exactly 5 seconds of not playing anything. And it's not like a it's a discrete static white noise, no no, it's more like garbage amplified to a high volume. If I start playing something again, the noise stops.

I have absolutely no idea where to look in order to fix that issue. Re-muting the channels and lowering down the Power Amplifier to 0 doesn't help at all (no influence on the resulting buzzing).

As a side note (but I should probably open another ticket), I'm unable to make it work with pulseaudio, or make applications consider the Power Amplifier channel as the master channel for volume control with ALSA (so apps can't change the volume).
uxalarm
 
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Joined: Sat Jun 04, 2016 8:29 am

Re: Audio noise when no playback with Cubieboard2 (A20)

Postby uxalarm » Sat Jun 11, 2016 5:02 pm

So apparently this still happens when the system is off but still powered up one way or another (microusb or standard power input). It is similar to touching the jack male plug with my fingers.

I don't have this issue with random other boards such as rpi (even the 1st generation), so I'll just assume the wiring of the jack output on the cubieboard is simply complete horseshit.

Now as a workaround, I'm considering trying the HDMI output, but I will need to buy something like a HDMI to RCA adapter. I don't know if that output will be better in any way, but what's worrying me is that ALSA doesn't seem to see the HDMI output (there is only one card visible, sun4i-codec).

Note: the buzzing sound can not be reproduced with headphones but only with amplifier/speakers plugged.
uxalarm
 
Posts: 4
Joined: Sat Jun 04, 2016 8:29 am


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