Power cables:
Suppose we could pug our device directly into the wall socket. WIthout any cable.
ANY cable used is going to deliver slightly less electricy than our imagined direct to the wall connection. No way to avoid this. The cable can only take away, not add, electrical power.
Now let us consider electric noise - again, the cable can only ADD unwanted noise, compared to our theoretical direct connection.
Bear in mind the electricity coming into the device is going to be transiting through an isolation transformer to remove unwanted noise, and will then be rectified and filtered into DC current. Unless the different power cables are somehow causing a differnt DC voltage and current to come out of the rectification and filter stages,
the device CANNOT sound different - the sound altering and producing componenets are running off of this DC voltage. Those componenets have no way of "knowing" which power cable is being used!
For aroung 95 to 99 percent of us, and our devices, the factory supplied will perform adequately, assuming the wall socket and the device power socket are in good working order and properly dimensioned.
What is that is not the case? Suppose are device has a poorly designed or performing isolation transformer, or you are plugging into circuits that are shared with an air conditionor, refrigeration device, neon or flourescent illumination? Again for 95 to 98 percent of us, upgrading to a power cable with twisted conductos and a mylar foil or braided mesh shield may help - you can get one for $30 - $50 off Amazon.
https://www.amazon.com/dp/B074GNL9G...onics&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw&th=1
If that doesn't work? A power conditioner such as Furman makes can be the answer - $90 to $400 depeinging upon the features and the capacity you desire - BUT you can hook multiple devices to it, whereas a power cables serves - one. Additional options such as hum filters and ground lifts are available. All of those will do much more for you than a high dollar power cable.
Anyone who claims otherwise needs to pony up proof, and more rigorous proof than anecdotal "I heard a difference".