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

@bigtwin Yes, that is my thought.   I have a friend who rebuilt his tube amp to sits on top of a bank of capacitors twice the size of the amp.  All the power cable has to do is keep the capacitors charged up. this is a very flat power demand.  

Cable deniers usually base their claims on their superficial understanding of electricity.  If you amp's average wattage is 240 watts, then you only need 2 amps and an 18 gauge cable is plenty big so 16 awg is "oversized".  What they miss is the extreme dynamics of the load in an amp where 50 amps might be needed for a picosecond.  

So if you have power available downstream of the power cable that can respond to these dynamic demands,  then the amp will be insensitive to power cables.  The cable only has to provide the nameplate wattage of the amp, which is relatively low. 

OTOH, I have a tiny little tube amp, a Sophia Baby, that weights 13 lbs.  I thought surely a 14 awg cable would be plenty for it.  after a couple of days of disappointing bass a friend suggested a bigger cable and immediate improvement.  In retrospect, it makes sense since this small amp has a minimal power supply.

Notice that I have ignored all the magic dust in $4000 cables.  All I have addressed is cable size.

Jerry

@panzrwagn No one here wants to listen to basic truths.  Shunyata, Synergistic Research, Audioquest, Furutech, and others have latched into a bunch of gullible dreamers with little common sense and no room for enlightenment. As long as they're not taking food from their kid's mouths let them have their little diversions. 

jacobsdad2000 - " Those of us who know are not listening. " or those of us that know are actually listening.

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.