[mythtv-users] rPi3 3.5mm audio out

[Peter Bennett]

On 10/20/2017 05:32 AM, Tim Draper wrote:
> i know a few people here use rpi3's as an FE - maybe you use the 3.5mm output also?
>
> i've recently tried to get one of my rpi's working with 3.5mm audio to use my conservatory built-in speakers. It kinda works but found i need to run it through an external amp to get any sort of reasonable volume out of it. So I bought a LEPY LP-2020A that has 3.5mm in, and i've bought a 4pin 3.5mm cable for the rpi side (a normal 3pin caused audio clicking but was fine when plugged into my phone for testing).
> this 4pin cable doesnt work at all with the rpi or my phone. i doubt it's a simple case of bad cable as i bought & tested 2 cables with same issues.
>
> what type of cable are you using? i thought i bought the right 4pin cable but with it working less than the 3pin i've obviously bought wrong. maybe i need to go 4pin on the rpi end, and 3pin/RCA on the Lepy amp end?
> ...or maybe you went for a DAC-HAT?
>
>
>
I also had very low volume. The fix was in software. No external 
amplifier needed.

Put  file .asoundrc in your home directory. I pasted it here 
https://pastebin.com/9viBwNMp
Select ALSA:default as your sound device (you may have to key it in if 
it is not in the list)
Add these to your .profile or somewhere it will run before you start the 
frontend:
amixer set PCM Playback 100%
amixer set Pre-Amp Playback  9

You can adjust the values as needed. You can also run alsamixer to see 
and adjust the pre-amplification.

I suppose I should add this to the wiki.

Peter