Which SR Blue or black Fuse

you need the large fuse, as there can often be a turn on surge with this pre it is worth going up a size and using the 6.3A. That’s what I used in my Ref 40. The black is good but the Blue is better and benefits from less need for burn in

Agreed - the Blue is better, at least in my gear.  You can always take the fuse out and check its size. (Power down the gear first ;))

Before Geoffy The Fuse Troll jumps in, remember that SR fuses are not UL or CSA approved. You still need a legitimate fuse to meet electrical safety bureau driven requirements. Otherwise, if there’s an electrical fire due to the equipment with the boutique fuse, your insurance claim will be denied. 

Better be safe than sorry. Spend the extra several hundred dollars on music. 

What a 🍆

I think the aftermarket PC are also not UL listed?