I asked the guy that did the tests linked in the previous page:
crazy-audio.com/2013/09/rasp … mment-1474
So, at least their audio card has no benefit from a very good supply compared to a very bad one.
You cannot know about other ones, but AFAIK it should not change much (even if the sound is affected, way below hearing threshold) and in any case throwing money for a PSU is not a good idea.
But hey, people can “hear” differences between USB cables…