I’m bound to regret this, but just can’t resist. So, on one side we have Ralph Karsten and Roger Modjeski (as well as almarg and other posters here)---two of the best living audio engineers in the world (I obviously place value in "authority"), and on the other side those who claim fuses are directional. And the explanation for Ralph and Roger (and perhaps Al, etc.) disputing the even possibility of fuses being directional (AC being what it is) is that they are "deluded amp manufacturer(s)"? Ay carumba! Very fitting in these Trumpian days.
I guess the designs of those two engineers sounding as good as they do it just plain ol' fortuitous luck. not because they know and understand what factors in electronic design lead to good sound. Thankfully we have some non-deluded audiophiles, not blinded to empirical findings by their knowledge and "beliefs", to keep hi-fi progress moving in the right direction.