“Black background” — What really contributes to this phenomenon?

I like the question. I purchased components already known for their quiet background. I really like a black background and low noise floor, silent computer, etc. And after getting a black background you just found out that your new noise floor is your tinnitus...

@yermajesty, Shielded XLR like the Mogami Gold 2534 can help IF you really have RFI/EMI problem, otherwise the 6db gain (or so) of XLR versus RCA will just raise your noise floor by 6db... I experienced the thing and got back to a good shielded RCA.