Headphones not working with Ubuntu 18.04.3

[linuxsheepdog]

Hello.
I installed Ubuntu (regular Ubuntu; not one of the other flavors) on an external HDD and are running it on an iMac. Anyway, the speakers work, but whenever I plug in my headphones no sound comes out. I've tried solutions online, but none have seemed to fix my problem.

I've attached the output from alsamixer as well as the sound settings page.

Thank you for your help.

[Autodave]

I have no idea about Macs, but I have seen this problem on PCs. Sometimes this will fix it, sometimes not. But, you have nothing to lose. Power off the machine. Plug your headphones in and boot the Mac. See if the headphones work. If they do, unplug them and see if the speakers will now work, too.

[linuxsheepdog]

I don't think just restarting helps. Thank you for the reply, though.

[slickymaster]

Thread moved to Apple Hardware Users for a better fit

[CelticWarrior]

I don't think just restarting helps. Thank you for the reply, though.

The suggestion was to shutdown ("power off"), not restart. And indeed you have nothing to lose so, why don't you try?

And are you sure the audio input works? And what kind of headphones are you using? And do the speakers work without the headphones connected?

[linuxsheepdog]

The suggestion was to shutdown ("power off"), not restart. And indeed you have nothing to lose so, why don't you try?

And are you sure the audio input works? And what kind of headphones are you using? And do the speakers work without the headphones connected?

It still does not work. They are wired headphones. As I said in my original post, yes, the speakers work but the headphones don't. Thank you for your help.

[CelticWarrior]

How are you sure the audio output actually works, or that it works with those particular headphones? Have you ever tested those same headphones with another OS in the same machine?

[linuxsheepdog]

How are you sure the audio output actually works, or that it works with those particular headphones? Have you ever tested those same headphones with another OS in the same machine?

The headphones work with macOS on the same machine.