Fuse heads,
I bit the bullet last week and ordered a SR 20 Black fuse which was marketed at 50% off the regular price. I tried the SR Red fuse in my Don Sach 6SN7-based preamp earlier this year and found no discernible difference compared to the sound of my system using $10 Hifi Tuning fuse. I just fired up the system with the SR 20 fuse and can say definitively that my system sounds fantastic (with a Dennis Had Inspire Bottlehead SET amp and Spatial Audio M4 Hologram speakers, and a modified Oppo 103 CD player). I hasten to add that the system sounded fantastic last night when I turned it off and went to bed.
So, I will run the fuse in and then have my pal swap the two fuse variants to see if I can tell any difference. It makes no sense that the fuse would improve the sound, but it is worth a few shekels to have fun trying it out. And obviously a lot of you "fuse heads" are devotees of the SR tweaks.
I will let you know my results in a couple of weeks. Cheers, Whitestix