Volume knob doesn't adjust headphone jack output

[paisleyboxers]

Should it be?

I can adjust with alsamixer, but not with the knobs.

```
$ cat /proc/asound/cards
0 [audioinjectorpi]: audioinjector-p - audioinjector-pi-soundcard
audioinjector-pi-soundcard

$ uname -a
Linux work-machine 4.9.40-v7+ #1022 SMP Sun Jul 30 11:16:10 BST 2017 armv7l GNU/Linux

$ cat /etc/*issue*
Raspbian GNU/Linux 8
Raspberry Pi reference 2017-03-02
Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, f563e32202fad7180c9058dc3ad70bfb7c09f0fb, stage2
```

[flatmax]

Hi there,

Yes, the volume knob adjusts the RCA lines. You can control the headphone levels using the Master control in alsamixer.
If you want hardware control you could setup two buttons on GPIO lines for headphone vol up and down. The idea would be to detect a button press on the GPIO line and execute a script which sets the Master volume, perhaps using the amixer command. For example to set the Master level to 0 dB, you can do that from the command line like so :

Code: Select all

amixer sset Master 0dB

Do you think this solution would work for you ?

Matt

[paisleyboxers]

Thanks for sharing! After I found a cable from monoprice I was able to test with a pair of headphones on the RCA output.

I suppose next up is poking around for a Fancy knob I could attach to GPIO pins unless someone else has a link to a favorite one.

[flatmax]

Please let us know if you find one.

thanks
Matt