Raspberry pi Zero W amixer: Unable to find simple control 'PCM',0

Dear all,

I have been looking for a solution to make my old school stereo “smart”. I have been playing around with my Raspberry pi, for different projects. But now I bought a phat-DAC and I want to use my raspberry pi zeroW to play music.

I have downloaded and etched everything and I can connect my phone and my laptop via bluetooth. However I have the following issue: I do not hear any music/sound.

I see this error: “amixer: Unable to find simple control ‘PCM’,0”

Can someone help me?

Just a small snippet:

01.10.19 19:23:43 (+0200) bluetooth-audio Setting volume to 100%
01.10.19 19:23:43 (+0200) bluetooth-audio Restarting bluetooth service
01.10.19 19:23:44 (+0200) bluetooth-audio amixer: Unable to find simple control ‘PCM’,0
01.10.19 19:23:44 (+0200) bluetooth-audio
01.10.19 19:23:51 (+0200) bluetooth-audio Bluetooth agent registered
01.10.19 19:23:54 (+0200) bluetooth-audio Device is discoverable as “BalenaSound xxxx”

Hey @DonTorbiera welcome to the forums and thanks for trying balenaSound!

I think the amixer error is to be expected when you’re using a Phat-DAC (I still see it on a working Phat-DAC setup here), but could you confirm you’ve set the device configuration variables as per the blog post? There are two changes to make:

Hi @chrisys,

Thank you for your warm welcome.

This is a screenshot of my settings…

image

So that is the same… What else could be the problem?

Hi @DonTorbiera hmm, you could check to make sure the audio device is set correctly. From the dashboard for the device, open a terminal session to the bluetooth-audio container and run aplay -l. You should see something like the below:

This only confirms the driver is loaded, as this will still display as per my screenshot even if you don’t have the DAC connected.

The next thing you can try is within the same terminal as above, run bluetoothctl. You should then be able to see your phone or laptop connecting. After you connect you should be able to see [CHG] Device <mac address> Connected: yes, and see the device turn off disacoverable and pairable. Then if you disconnect you’ll see it turn discoverable and pairable back on.

It would be good to know if you hear the connect/disconnect noises out your speakers when you connect a device. If you don’t I’d be concerned that either the DAC or connection to your stereo is not working. To test this even further, from the same terminal you can run speaker-test -t wav -c 2, and you should hear a voice saying “front left, front right” out the corresponding channels.

Let me know how it goes!

Sorry for the late reply, but I was not at home during the weekend. I have been checking the solder points (with a multimeter) and all is fine. I only hear cracks actually… Also when i run speaker-test -t wav -c 2. With multiple speakers … Is there another way to test it?

@DonTorbiera if you’re only hearing cracks/crackling when running the speaker test then something is most likely wrong with your hardware or connection to the stereo. What about testing it with some headphones plugged directly into the 3.5mm jack on the Phat-DAC?

Dear chrisys,
The result with headphones or other speakers is the same.

@DonTorbiera based on everything you’ve described, it sounds like you have a faulty Phat-DAC. I would recommend trying a complete re-flash and re-install of everything and without even trying any bluetooth connections, go straight to trying speaker-test. If that’s crackly then it’s got to be your hardware.