Cesar, I don't have the 45TX, so I can't specifically comment on its USB input port; however I do use the USB output from my laptop to feed classical music streamed from stations all over the world into one of my receivers, using the Xitel Hi-Fi Link connection. The quality of streaming audio isn't the highest to begin with, but for example when I compared the quality of a local station received over the air with the streamed signal of the same station there was just the usual quality loss because of the reduced bandwidth. So, although you didn't describe what material that you were listening to, my thought would be that since the USB to USB connection is a straight digital one, that the USB shouldn't degrade whatever quality is available originally in the source material.
