I recently purchased the AH Platinum Ref fuse for my AR Ref 3 preamp.
I do agree the preamp sounds superb with this fuse!
But... it also sounds superb with the fuse that came in it - which may not be the stock fuse - it doesn’t look like a standard fuse with just a wire, but has a more complex element in it (it is glass, so I can see the element).
And... I must say I’m at a bit of a loss to report the AH fuse is "much better" in any respect.
I’m a bit inclined to think that many with such investments in their fuses "want to hear" significant improvements over their stock fuses - and that there is significant "placebo" effect with fuses as with cables.
But... hey... "to each his own."