Islandmandan, I envy you the capability to invert easily, but I do not know how thee PS Audio does this. If it adds another stage, this sorely disadvantages the inverted sound.
As to how you can know, it is my experience that on many records you can hear little difference, but on some it is striking. Remember also that recording engineers may change the absolute phase between cuts further complicating the issue. Your ears are your only recourse as usual. I have lacked the capability to easy change phase for years and am certain that at least some of the records that thrill me are those that accidentally have correct phase for my system. I will also say that the quality of your vinyl front end including the phono stage can be far more important than absolute phase.
As to how you can know, it is my experience that on many records you can hear little difference, but on some it is striking. Remember also that recording engineers may change the absolute phase between cuts further complicating the issue. Your ears are your only recourse as usual. I have lacked the capability to easy change phase for years and am certain that at least some of the records that thrill me are those that accidentally have correct phase for my system. I will also say that the quality of your vinyl front end including the phono stage can be far more important than absolute phase.