What was the first power cable that you noticed a difference in the sound?

I have bought six or seven different power cords, none over $500 and have noticed little or no change in the sound of my system. All the cables are 12 gauge or bigger.  Without talking about cables made with unobtainium, where did you start hear a difference.



@curiousjim Master Couplers are all over used sites, I’ve bought 5 or 6 of them from ebay or audiomart etc. SR doesn't make the anymore.

"Better yet, separating digital front end with a separate power bar from the one used for the preamp and power amp." @riccitone 
Does everyone do this? Sounds reasonable to me . . .

@carlsbad2  I find your first suggestion very interesting.  If I understand you correctly,  there are amp designs that manage power in such a way as to make power cables a non issue, assuming of course you are using any decent cables that can carry the required current in the first place.  My last three amps have all been Hegel products.  H390 to the H590 and currently a pair of H30s.  I have heard zero difference it sound regardless of the PC I've tried.  Was using Furutech DPS-4.1 and currently using Puritan Ultimate.  Throw the stock cable that Hegel supplied into the mix and the sound is the same.  Will I hear an improvement if I spend thousands on the PC?