I may go to a 3.25A slow blow as I have a Phillips Dario Miniwatt GZ32 that has blown out the 3A fuse. I checked with Dan and he confirmed 3.25 would be totally fine.
I had the same problem with a crappy rectifier tube - and could only find a standard 3.25, which works fine.
HiFi Tuning FuseI've just been A/B'ing the standard fuse with the HiFi Tuning Fuse, and feel a little sheepish in saying that their is a noticeable difference:
First of all I did not find any directionalty in the HiFi fuse - no, it sounds the same plugged in either direction.
The HiFi Tuning fuse has a more air and separation around the instruments, which leads to more clarity. This doesn't mean the standard is warmer, but sounds the standard more opaque with less detail. How much more detail? Well equivalent to an IC or PC change - is it worth it? Definetly, for the price of a pizza its a steal.