I have been in this obsession (euphemistically, a "hobby") for some 50 years and I can still hear the better part of the human range. The SR Purple Fuses are major -- repeat major -- audible improvements, both in my VTL 7.5 iii preamp and more latterly, my Sansui TU-X1 tuner (ca. 1979), often regarded as the finest tuner ever made. I am beyond audio "snake oil" and can hear -- or not hear -- the difference.
I don't know the physics, but with my simple but experienced ears, I do know you have to tell which fuse's end is in and which points out, to hear which way is better. Neal