For some reason, 18.04 beta 2 has decided it wants to output sound via my Samson Meteor Condenser Mic instead of the analog output. I can select it in the Raven panel or Sound control panel, but it does not persist between reboots. Also the default sound is blank.
Sounds like a pulseaudio issue. Especially since you changed it via the sound panel.
Please run
ubuntu-bug pulseaudio
This will report the issue on launchpad so that the developers are aware of the issue and can advise further.
Thanks, I did it when you said but I forgot to update this thread.