@gbmcleod - in my initial posting, I also said to be careful with Furutech fuses. They are very revealing and VERY TRANSPARENT. This means that it will reveal problems or inadequacies in areas of your system that other fuses may compensate for or mask thereof. An example would be a preamp with a somewhat undersized power supply. The Furutech fuse being fast and transparent can cause the preamp to sound lean in the bass/midbass area because the power supply does not truly have enough capacitance to keep constant voltage on the large waveforms (and even the midrange waveforms that can become shouty/forward). A fuse that will slow down the charge/discharge and make this preamp sound warmer and fill in the bass/midrange area.
As I have said, the Furutech is very revealing of problems and it may not be the path that everyone want to start. You may end up working to fix every other problem/characteristic in your system. However, if you choose this path, the end result will be the very best (in my opinion).
@fourwnds - I have also had similar experiences with SR20 fuse. The SR20 is very fast and very clean. It is so clean that it almost becomes artificial to me (almost similar to a silver fuse) and I lose emotional contact with the music. I have also experienced where the bass is definitely lean with this fuse. Trying a Hi-Fi Tuning gold (discontinued)fuse was an improvement and the sound was a lot warmer. However, over time I determined that the Gold has somewhat of a metallic edge to the sound and it wasn’t the fastest fuse. The HI-Fi Tuning Supreme (silver) was nice, but it had that push in the upper mids (silver) that caused it to be less natural sounding to me and more artificial. This may be a good mating with tube equipment or very slow/laid back stuff.
I encourage all to re-read a history thread:
https://forum.audiogon.com/discussions/direction-of-aftermarket-fuses-only-for-believers
A lot has been discussed here on fuses, and it’s not a 4,000 post thread like the "RED thread".