I’ve got old good M-Audio Revolution 5.1 (VT1720/24 [Envy24PT/HT] PCI Multi-Channel Audio Controller). I’m sure I had additional regulator at KMix with my older system (another KDE-based linux disrto). Now (openSUSE 12.3) KMix has very limited set of regulators both for input and output. Is there any way to bring them back and therefore be able to use headphones output?
A general reply, without delving into the details of your system is if you are using pulse audio, for many users it provides them greater control over the use of their sound device(s) with different applications. There are a couple of blog descriptions on how pavucontrol is used:
You could thus install pavucontrol and using those blogs as guidance try to configure your headphones.
If the above does not work for you, please post here in this thread, and we will give you some commands to run a diagnostic script on your PC, which will provide us with more information that will hopefully point to the root cause of your headphone output problem.
Good luck, and WELCOME to openSUSE forums, and thank you for posting on our forum.