So I thought I would try out the SR Black fuse. The seller advised to start with my preamp (AR Ref 2) and so I did. With about 20 hours of use, I have to admit I am beyond surprised at what an improvement one little black fuse can make. The black fuse was very noticeable in a couple of areas, 1), it made the mid range sound better in terms of focus and transparency, a smoother and more natural sounding presentation. 2), base range is deeper with more impact but not more bass if that makes sense. I would like to thank those who responded to share your experiences as well. Next step is to install the SR black fuses in the kismet in khartago mono amps