Well, it might be anything. My observations tell me that headphone amplifier is just turned off, so the audio has a weak signal and it works properly only with external amplifier, which also may suggests why speaker doesn't work at all. So it's maybe only a matter of one pin set to high.
As far as I noticed this audio issue happens mostly on RK2705, while on RK2706 the same code runs ok. Perhaps the first one needs a special external power sent to the headphones.
Please note that the audio problem occurs only with simple headphones WITHOUT amplifier. I plugged it into pc speakers and it works fine. And someone else here plugged it into wireless headphones (with amplifier) and it also worked ok.
|