You still know how much it costs and presumably you’ve read some glossy/reviews (grey area) before trying, that’s an expectation “potential”.
Power cables are also part of another chain, it’s a long dirty one and you can only “fix” the last meters. It’s worth considering the logical implications some.
Each on its own.
You can never remove money from the equation. The loan of a product to try is known as ‘The Puppy Dog Close’, You get the puppy home, it looks cute, you feel it, you touch it, you own it. Also many people just feel obliged to buy and don’t want the, what they feel as, confrontation of bringing it back.
Some cables look pretty cool, too.
Why do you not answer my question?
Is it necessary that it is 1m? Would half a meter be also efficient? Or 1cm or better 1mm.
Not really,
DC quality is dependant on the ability of the power supply to convert the AC.
I think shielded power cables can prevent stray electrical noise & radiation entering non shielded, unbalanced audio signals.
If your Hifi equipment power cables run close to analog signals which are unbalanced and unshielded, a shielded power cable could be helpful. But… I would not spend alot of money chasing improvements.
Something from Belden or equivalent would be perfectly fine, and likely offer a higher quality/performance ratio than “many” so called brand leaders which don’t have shielding.
https://www.parts-express.com/Belden-83803-12-AWG-3-Conductor-Power-Cable-USA-100-790
Other than that, I don’t believe power cables are likely to make any difference, other than psychoacoustic. Spend money elsewhere for bigger gains.
I personally run an Isotek Evo3 Sequel on my Firstwatt F7… but it came with the amp second hand. I never bothered to AB compare.
FWIW I think this post distills to cable common sense. Don’t buy rubbish but once you get to “well made, to spec and reasonably priced” there’s little need to look further.
I’ve used several of those DIY cables. Good quality, but they are a bit stiff on short runs. If you need flexibility, add additional cable length,
A key component is a firm connection. Hospital plugs and hospital receptacles are a good solution. Thousand dollar power cords are overkill. I use good receptacles, and good cords, most of which I bought used or discounted.
It’s not something I’d have advised but only because I’d not considered it. They’re not given to wasting money on imaginary/edge-case issues either.
I’ll investigate this option as it appeals to my way of thinking. All good common sense advice.
The higher quality receptacles actually hold the plugs far better. Darn things are always working their way loose otherwise.
UK plugs are generally a little bulkier and better behaved. I’m still looking into this though. My power bank is cheap crap and a trip hazard. I’ll not throw money away but would still rather “waste” a modicum of cash than cut a corner. Thanks 
I have mostly midgrade Cardas and Audioquest Vintage Cords. I usually end up buying from folks who upgrade to the lastest and greatest.
I’m a big fan of regenerators and conditioners.
The principal determinants of sound quality in your listening room, given the limitations of a particular recording, are the loudspeakers—not the electronics, not the cables, not anything else. This is so fundamental that I still can’t understand why it hasn’t filtered down to the lowest levels of the audio community. The melancholy truth is that a new amplifier will not change your audio life. It may, or may not, effect a very small improvement (usually not unless your old amplifier was badly designed), but the basic sound of your system will remain the same. Only a better loudspeaker can change that. My best guess as to why the loudspeaker-comes-first principle has not prevailed in the audiophile world is that a new pair of loudspeakers tends to present a problem in interior decoration. Swapping amplifiers is so much simpler, not to mention spouse-friendlier, and the initial level of anticipation is just as high, before the eventual letdown (or denial thereof).
Not sure I’ll be joining you there but we know the debates inside out. Started googling hospital power gear already 
Speakers are an important component. For my setup, they are down the pecking order since my primary (90%+) use is headphone listening. I have more money tied up in headphones than I do speakers. My speakers are good quality but kind of dated. Monitor Audio Gold Reference (3 sets).
I have stable power. Very little oncoming distortion (less than 2% THD). The regenerator quashed that to almost nothing. Pricey tool, but I’ve had at least one for nine years. I would definitely keep one in my main system. YMMV.
The biggest determinant of sound quality is the room, not the loudspeaker.
How acoustic energy interacts with the room is key and fundamental to good sound, which is why a focus on room acoustics/correction/speaker directivity is very very important.
But yes obviously a loudspeaker is important. But so is the source, amplifier, room correction, DSP, your hearing, etc. Everything matters.
Amps are one of the most important aspects.
I have heard significant differences between amplifiers. I.e. Valves, Solid state, Firstwatt, Class D, etc all sound drastically different; in presentation, tone, detail, frequency response, power output, presentation, imagining, voicing, impedance matching to source/preamp, and how they handle impedance swings.
Possibility smaller differences “might” be observed between amplifiers of the same “class type”.