Fuses do NOT make ANY difference to the sound. Anyone not agreeing suffers from the audiophool syndrome. There will be scandalous resistance to this comment but just take my word for it.

Use UL approved, slow blow properly rated fuses which came with your system originally.

If you are still popping them, there may be a fault in your system.

Remember, fuses pop for a reason (typically to avoid a fire). Do not do anything weird (like installing higher rated snake oil fuses) to give the insurance companies any excuse not to pay for your burned down house.

I have the same Cary pre-amp with the orange fuses and I didn’t have to go to a higher value. I also have some exotic 6F8G and Marconi BL-63 tubes installed in it. My Cary amps are another story however as they will blow at the stated fuse value needed. 

My Purple Fuse blew after only a few weeks. It uses the same Large, Slow 2A as the previous Orange and Blue fuses, which had no issues. I have advised the retailer and expect they will replace them, but what comfort do I have the next one will repeat? And I really thought the Purple was a major advance.  Neal

It’s interesting that I have only had problems with SR fuses and not any other standard fuse. They were all slow blow and even rated at two levels above the standard. My preamp manufacture cautioned about using a higher rated fuse and I didn’t want to get into a warranty dispute in case I had a problem.