Fuse upgrades? -- 6.3 amp 250v 5X20mm fast blow fuses

sleepwalker65" I am very well-informed, having an engineering background and work in the broadcast media industry. I know what limits the DC power supply places on sound quality, and fully understand the ramifications of placing a weak link in the chain of power delivery. Your comments betray a lack of understanding of how power supplies function.'

Your posts are those of a fake, a phony, a person "pretending" to be an expert when it is apparent from this post and your previous renderings on this site that you are confused, disoriented or just misinformed many posters hear are actually in elementary school and you would appear by all evidence and available examples to be one of them but I suppose you are having fun which is fine but other's here who are experienced, knowledgeable and informed are free to question, challenge, and refute your pronouncements, declarations, and edicts. 

sleepwalker65
You can choose to believe in unquantifiable properties, while I believe in the works of the esteemed scientists who authoritatively laid the groundwork of all modern electrotechnology: Georg Ohm, Heinrich Hertz, James Watt, Joseph Henry, Alessandro Volta, André-Marie Ampère, Michael Faraday, Charles-Augustine de Coulomb, Nikola Tesla, Gustov Kirchoff, Thomas Edison, John Bardeen, Walter Brattain, William Shockley and many others. Believe what you want to, but please refrain from disparaging others.

Best Name Dropper of the Week goes to....sleepwalker!

Joke. Who invented the steam engine? Watt. Who invented the steam engine? Watt. Who....

Couple of additional thoughts.  You may not hear a difference with fuses.  Your equipment/speakers may not be high enough resolution to hear the differences.  On very warm equipment, just putting in one Hi-Fi Tuning fuse may not may any significant amount of difference (especially if there are 3 other fuses that are working in conjunction).  If you have 4 internal fuses on the DNA, I would suggest upgrading all 4 of them to get an "idea" of what a specific fuse is doing.  I suspect they are all post-transformer or post-regulator fuses (2 for each channel).

@auxinput I agree, any fuse that comes after the power supply filter capacitor(s) has potential to affect current delivery and hence sound quality. For that reason, I prefer fusing only on the power transformer primary side, where it should have zero impact if not sized too conservatively. Also, I prefer fast acting fuses on everything except the power amps, due to the nature of high and very brief instantaneous current demands. As usual, in keeping with safe operation, as long as the manufacturer recommends a slow-blow fuse, that is the only situation when I would use one.