Furutech Nanoflux speaker cables

Are Furutech Nanoflux speaker cables directional?  If they are how do you know which is the amp end and which is the speaker end?  I only found one article at Positive Feedback that said the noise filter should be closer to the source but I haven't been able to find any information that would confirm that and the person who lent me his cables swears it goes the other way.  I have listened, and do hear a real difference but it is unclear to me which is "better".