Similar problem, but what I needed to do (after something half-fried my internal sound chip - I get a squeaky sound only on the right side) was to rename the kernel module - it was *snd*intel ("find /lib/modules/... | grep snd\*intel") so it would not load and the USB headphone device would then become the ONLY sound card. There is probably a way to reload the main sound.
But either Flash, vlc, etc. need to be fixed, or there needs to be a virtual sound device that implements the "first" device in such a way it can be switched between physical hardware.
Similar problem, but what I needed to do (after something half-fried my internal sound chip - I get a squeaky sound only on the right side) was to rename the kernel module - it was *snd*intel ("find /lib/modules/... | grep snd\*intel") so it would not load and the USB headphone device would then become the ONLY sound card. There is probably a way to reload the main sound.
But either Flash, vlc, etc. need to be fixed, or there needs to be a virtual sound device that implements the "first" device in such a way it can be switched between physical hardware.