Upgrading Fuses

"I've never found hypothetical scenarios very interesting or productive"

Filtering out noise on the input side of stereo equipment is very basic stuff. My guess is that some of your own equipment has ac line noise immunity/voltage tolerance specifications either in the manuals in or available from the manufacturer. It is what it is and there is no need to accept my word for this, a quick bit of research will allow anyone to confirm.

Personally, I think you need to look at the science on tweak threads like this as well as the listening test reports. If you only consider the latter then the only answer you'll ever come up with is "spend the money", placebo effects and the occasional shill tend to always push the testimonials toward the plus side.

The fuse will make no difference to the audio; however, it will make a difference to your billfold.

A fuse is a safety device that lies in series in a circuit between an electrical source and its associated load(s). When the current, or flow of electricity, exceeds its designed threshold, the fuse opens.

How can one 2 amp fuse differ from another, assuming they are both designed for your circuit?

How can a power cord make a difference?
It does.
How can interconnects make a difference?
They do.
I don't mean to be snide but this have been discussed to death already. Some of us hear big differences that we can't put into words, but they are there. Maybe its just a matter of being better built: that justification seems to apply to all things audio. Or it could be that there is something else at play here. I've replaced fuses on circuit boards that gave bigger results than the one I replaced on the slide out on the IEC jack but there were still improvements.
I simply can't explain why I hear a difference but I do.

Have you ever noticed how the "this can't work" crowd never talk about actually trying the products they denigrate? It really is unbelievably boring and pointless. It's like hanging out at a car collector convention just to nag everybody about how "one car is just as good as another, quit wasting your money." It's sad. YAWN.

"never talk about actually trying the products they denigrate? "

If we did I think they'd revoke our engineering degrees:).

Happy listening.