Power cord - 5 ft vs 10 ft ?

Two days ago I borrowed a mains noise analyzer from my local dealer. I learned how much noise is on the regular ring circuit in my listeningroom. I was surprised at how much noise was on my dedicated 20 Amp circuit. Radio broadcast, static,etc. I was also surprised at how much noise was coming off my 100 pound lead acid battery.

I inserted a transparent audio powerwave which tested at virtually noiseless. I used a high quality "audiophile" type power cord to provide power to the powerwave.

I was gratified that it greatly reduced the hum from my two 45 tube monoblocks.

I checked the noise off of an extension cord that was plugged in to the powerwave and was surprised at how much noise it picked up. It was not a shielded cord so perhaps that should have been expected.

From this I’ve decided that I’m going to have some kind of power conditioner in my system.

So this comment is not purely about power cable length. But I thought experience. 

@jumia Thank you for your kind comment about my record collection. It has been fun and still is growing, though at a slower rate. 

How do I choose what to play? Great, great question. Believe it or not, mostly i am streaming these days. Saves wear and tear on the cartridge and it is really stressless. Through my bluesound node2i and my orchid it sounds pretty good.