JohnSwenson;541039 Wrote: 
> Thats not correct, the Wolfson DAC is only used for the internal speaker
> used for the bleeps and blurps etc. The AKM chip goes to both the
> headphone amp and the analog outs.
> 
> The analog outs have a resistor and one cap in the path between the DAC
> and RCA Jacks. The headphone out has a cap, resistor, the headphone amp
> and another cap.
> 
> There is no way to have different volume for the headphone RCA outs,
> they are the same.
> 
> The headphone out can also be shared by the IR blaster circuit. There
> is an enable signal to each (headphone amp and IR blaster). I haven't
> looked carefully at that circuit to see exactly what it does.
> 
> The S/PDIF input comes directly out of the main processor as does the
> two I2S streams that feed the DACs. All three of these are reclocked
> after the processor. There are two clock muxes, one for the Wolfson and
> one for the main audio which clocks both the S/PDIF and the AKM DAC. 
> 
> I think the headphone amp is running off a separate regulator from the
> rest of the audio circuit. I think there is a DC-DC converter to get a
> higher voltage for the headphone amp. 
> 
> John S.

Thx for clarifying that. I didn't have a chance too look inside. 

I just took my conclusion from looking at Alsa, where you see three
different sound devices. Usually PC-speaker is not a device under Alsa
on a normal PC. That's obviously different in the embedded world .

One secret after another gets lifted. ;)

Cheers


-- 
soundcheck
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