Thanks goes out to Roger Modjeski for bringing this to the attention of Music Reference owners. Roger carefully chooses the fuses used in his amps. He doesn't like to repair amps & neither do I.
Fuses that matter.
I have tried six different fuses, including some that were claimed to not be directional. I have long used the IsoClean fuses as the best I have heard. No longer! I just got two 10 amp slow-blows WiFi Tuning Supreme fuses that really cost too much but do make a major difference in my sound. I still don't understand how a fuse or its direction can alter sound reproduction for the better, but they do and the Supreme is indeed! I hear more detail in the recordings giving me a more holographic image. I also hear more of the top and bottom ends. If only you could buy them for a couple of bucks each.