Clean Power without the drawbacks of Conditioning Filtering. Advice?

Sadly, my efforts are more like a two year old child's... I poke and hope, then whine because I am not getting immediate comfort. Alas for my computer skills. I have none.         
In college we punched cards in the 'most advanced computing' class. It turned me off to computing for life.. sadly.                   
Now I bask in my geezer-ette golden days, fondly remembering when Telephone books were the high tech solution to finding something you needed.

I use a ’extension’ cord. actually two, I made myself. 34 ft and 42 ft.The wire I used was MilSpec 12gauge silver plated, Teflon insulated 600V in quad twist (so two wires for each plus.minus) wrapped with Teflon tape. Then two solid 2 gauge ground wires between the two quad twist sets. all wrapped in another set of Teflon tape. The whole is about the size of standard Romex. (at 9 gauge equivalent) At the wall, I use a pair of Furutech ’28’ Rhodium plugs into a Furutech GTX NCF Rhoduim Duplex.
At the equipment end, I have them split, one quad goes into a small electrical box on the floor with one duplex, then the wires out to a second box on the floor with twin duplex. This set powers my two conditioners and a few bits like the wall wart for a TT.. The second longer quad goes to the amplifier. where it too is ending in an electrical box with two duplex, one Furutech GTX-D gold, the other Furutech GTX NCF Rhodium So I can plug the amp in either as I please.
So this is just my choice for stuff I used to make my own extension cords.One device you can use to ’clean’ a bit is something like the PS Audio "Noise harvester" (currently a few places are selling them for $50 each if you buy at least two of them, which is a good deal as they list for $100 each) You can plug them into unused outlets around the system. There are others, more expensive, but they also do a better job, unless multiple PS Audio gizmos are used.. So it is a tradeoff.                               
The boxes I used are just in wall types that look like a box. Made for a duplex or two.You could use common bulk wire from a hardware store, or more fancy wire. Your choice. I used to use common heavy duty Pass Seymour duplex. for years. Only recently went up to the fancy AC duplex.

Geoff, seems no way to find whatever link you say exists for David Magnan. The cable site with his name no longer shows any such DYI. and is no longer owned by him. And Googling his name does no better. So is there a LINK you have, or know of that actually gets one to the place where he shows this device? Or a wayback machine http link to it?

Dirt cheap.. Plain old small quartz crystals, add a bit of automotive dielectric grease to insulate individual crystals, place in small baggies...(I do 1/4 inch thick, about 2 inch by 1.5 inch packets.)I put some in the AC duplex area and in and on the AC Plugs.Seems to work well as I just bought some PS Audio Noise Harvesters, and they register zero noise on that line. It may be luck and it may be my notions have some merit? I wrote a new thread about the noise harvesters,                                
https://forum.audiogon.com/discussions/discovering-i-may-have-the-cleanest-ac-power-in-usa

My final suggestion is a better AC duplex to feed the power.I would suggest Furutech, or Oyaide. Others may suggest other AC duplex products. Then a good powercord from said duplex to the amp.

I think the op went and bought the PS Audio P20.             
It was the highest priced suggestion. The lowest price suggestion: Right here: Carol wire 12 gauge/3 for about $1.50 a foot from a hardware store. An ordinary in wall duplex tandem box, $4 a Wattgate plug $12 Two Pass & Seymour heavy duty 20 amp duplex, $12, And a brass tandem duplex cover $4

As mentioned many times... The audiophile mantra: " why spend $20.00 when you could spend $10K.. " Truer words never spoken.

I have split analog from digital.. I use a Furman REF 20 for analog, and the PS Audio P-600 regenerator for digital, and run the 600 to output 110Hz instead of 60Hz.Until I bought a new  $$$ (with 5yr warranty) And felt I could not plug the new Marantz into the 110Hz device in case of a warranty problem.                            
Since the other digital really sounds better with the 110Hz.. I placed the Marantz on the Furman. Since the high current area of the Furman (which I use for preamps and phono boxes) is isolated from the low power section. I an confident the Marantz is not adding grung.(And using PS Audio Noise Harvesters, to sniff out hash on the AC line, The Marantz AC backwash has no HF 'spew' Unlike some of my other equipment. (the Plasma TV is a huge offender, but thankfully only when turned on)           
So basically only some audio boxes spew stuff. Some digital devices add nothing bad to the AC line. Finding out which ones DO, is valuable.