@pinwa
I looked at Furutech’s website as quoted by @gkelly, and assumed that, like Oscar Wilde, you would be easily satisfied by the best! Sounds as if you knew the answer anyway because you borrowed custom cables terminated in reverse.
Furutech also says its NCF "generates negative ions that eliminate static. Second, it converts thermal energy into far infrared. Furutech combines this remarkable material with nano-sized ceramic particles and carbon powder for their additional ’piezoelectric effect’ damping properties".
As a physicist I am sure you will agree that negative ions increase static, which is a surplus of electrons. As for converting thermal energy into infra-red, that’s what everything does around room temperature. But wait, there’s more: mechanical vibrations are converted using the piezo effect into yet more electrons, presumably to give some added snap, crackle and pop!
But now I am really confused - the borrowed cables have spades on one end and bananas on the other and you hear a difference when they are swapped, but your speakers only accept spades. What gives?