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

With one exception, I’ve never noticed a difference.

The exception is the power supply running from the controller on my turntable that runs to motors (VPI Avenenger Titan).  It ran very close to the cables coming off my tone arm and created a distinct hum.  Replacing with a nice cable stopped this.

mind you:

1.  I’ve taken care to route power mains away from interconnects, only crossing at 90 and never running close parallel.

2.  All power supplies are already post-filter

3.  I’ve used heavy duty mains on everything.  (So low gauge, heavy duty, nice wires, but talking New Egg computer mains, not super high dollar audiophile brands.  Just big wires with lots of shielding and hospital plugs routed at a distance.

Oh, caveat #4,  all my interconnects (excepting coming off the turntable) are XLR fully balanced, so less susceptible to interference.

@dill perfect, now I can have my coffee knowing you are listening. 

when i used power cord, i was able to power it up and get sound and when i disconnected it, i really heard no sound. that's how i first time heard differences.