Geoff, I have 4, 10A fast-blow fuses in my big amp. I have a better chance of winning powerball than getting all the directions correct at the same time, and there is no f'in way I am going to sit around and try listening to every permutation. The amp manufacturer used Hi-Fi Tuning fuses in the amp, and showed me which way to orient them based on their arrows and the direction of electricity flow. If the SR fuses had an orientation indicator (i.e., arrow) then I would know how to orient them.
If SR is going to charge $100 bucks for a fuse, it seems they would take the time to test which direction their fuses sound best and then label them. I am not saying they should test every fuse but, IF this direction thing is true, there must be a reason they sound better in a certain orientation and it must have to do with manufacturing since the parts at each end are the same. So, what is left, wire direction, which end gets soldered first, which direction they run their
2,000,000 volts of
Quantum Tunneling
electricity, what else? If SR can figure out which of those things affects directivity, then they would know which direction to paint an arrow on the fuse since they are all presumably manufactured in a sequenced manner. Some might say the absence of an arrow on their fuses indicates they think the orientation issue is BS. OTOH, watching audiophiles fumble with the direction of fuses probably gives them a laugh or two.