Pre-amps with seperate power supplies .....

Yes you can change it to a better cord and it will sound better. If you sell it then just be clear on what you have done. I have changed and in the end improved lots of stock gear with better quality parts. Yes, we need to clearly point out any mods when sold.

Goodness the level of improvement afforded by simple mods is both staggering and relatively cheap. Better caps, resistors, wire, attenuators and on an on.....high end stuff is often built with embarrassingly cheap and inappropriate parts quality for the selling price. Yes, $10,000 plus speakers with $8 caps in key positions that sound ok, but can be greatly improved.

I have seen many $3000 - $4000 preamps with a poor sounding ALPS pot when a nice stepped Attenuator would elevate the sound in a stunning manner.

It`s true different and better aren`t the same.Can many audio components be improved upon? Yes! Grannyring is right in that lots of part choices are compromises by the builder to control cost and stay within a certain price target.Certain higher quality capacitors,resistors,wire,etc. wouldn`t be cost effectively for the manufactuer but can easily be improved by the owners of these components.Look at the standard power cords components are shipped with for one example of cost cutting.Of course the range of "part quality" compromise varies from one builder/brand to another.

Usually a very slippery slope regarding resale,sounds better and any other reason you want to use to mod/change a factory item.My attempts on that merry-go-round is a 25% success ratio,good luck,Bob

"thank you and who built the cord for you ???"

Modwright made them.

Unless a PC carrying DC is immune to RFI and EMR, unless the resistance of a PC is irrelevant with respect to speed and dynamics of transients, and unless the quality of the terminations is somehow also irrelevant with respect to DC, I don't know how the quality of the umbilical could not make a difference.

There is a reason why Tesla won out over Edison. I would think the quality of the cord might be more important for DC.