ron1319,
I am going to buy a USB cable because even though I’ve only listened to one of them so far, I’m 99% sure I will be able to differentiate between my printer cable and the better USB cable blind. My current belief is that the difference wasn’t subtle which is not what I expected.
Have you ever considered, just for the heck of it, having someone help you with a quick blind test of your cables. If you are getting new USB cables, that should be a pretty easy swap.
In my case my source equipment is in a different room from my speakers, so that makes it easier to set up a test where I can’t see/hear what’s going on during the swapping.
Though even if you have your source in the same room as the speakers, I"m sure you could do a blind test with someone helping so you don’t know which cable they swapped in. It may not pass peer review...but even informal blind tests at home can still be somewhat surprising and mind-opening :-)