Speaker cables - cables make a difference

@audphile1 

I usually completely eliminate the noise floor by turning off my amp

Ah, the ultimate proof that everything makes a difference 

@richardbrand indeed. 

here’s a crazy thing I’m trying to explain to myself…I have a theory or 3 but I won’t spill the beans yet…

here is a puzzle -

I have two power cords, Kimber PK10 Ascent in 2m length, PK14 Ascent in 1m. When I swap the 10 out with the 14 on my integrated, the sound becomes livelier, with faster transients and better instrument separation with the 14 gauge power cord. Same outlet and circuit. The sonic outcome is repeatable. I had no expectations for this swap it was done to speed up the power cord break in when I bought the 14. Consistent before, during and after break in.
Same results are obtained on my DAC but that’s even with the 2 cords of same length but different gauge (I have 2 PK14 cords one is 2m the other is 1m). Like I said I researched this after I thought about the reasons why to see if my thinking was in the right direction. 
I’ll add…I continue to use the 10 on the amp and 14 on DAC and phono stage. 

@audphile1 

Have you got any ferrite rings?  I am wondering what difference these might make placed around each end of a power cord.

I mention this because I have a KEF subwoofer in my motorhome.  The subwoofer with its built-in class D amplifier emitted so much EMI that it completely blocked digital TV reception, coming from the nearest tower.  Adding two ferrite rings to the subwoofer mains cable reduced the EMI and restored the TV signal.  This is completely objective and repeatable, no golden ears needed.  The effect operates regardless of whether the motorhome is connected to mains power or is running 'clean' power from batteries via a sine-wave inverter.

My thoughts are that mains cables can make a difference, but it has little to do with 'cleaning' up the incoming juice.  If there is significant EMI generated in a component, the power cable can act as an antenna.  Changing the length of an antenna changes its tuning!

@richardbrand that is a good thought however, the power supply in my Meitner DAC is enclosed in a faraday cage and the underside of a top lid has an EMI blocking sheet adhered to it. I have an EMI measurement tool and it reads nothing. 
The boulder amp has a transformer that’s located towards the front of the amp. It measures nearly nothing by the business end of the amp. 
I do not have ferrite rings on power cables. They are shielded. They emit very little as well. The system noise floor is extremely low, even with speaker cables connected. Lol

The difference is audible between these different gauge cables even with ones in identical length. I continue to use the 10 gauge on the amp because with the 14 it sounds a bit thinner at times. Better synergy with the 10 there. 

Don’t want to high jack this thread. Plus I’m sure some will want to call me delusional, especially those who think power cables can’t affect sound quality. The results were unexpected and caught me by surprise. If I have time this week I will call the folks at Kimber Kable to get their take on it as well.