HiFi tuning fuses, some benefits help

I haven't tried them, and I don't intend to. Therefore I won't express an opinion about their performance. But I would suggest that you consider the following:

1)It would stand to reason that in some fraction of the cases where improvements were noted, the real reason might simply have been that several year old fuses, whose surfaces were dirty and oxidized, were replaced by new fuses with clean (and oxidation-resistant) surfaces. It might be worth first evaluating your existing fuses after treating them with a contact cleaner.

2)It would seem pretty clear that the differences, if any, would be dependent on the design of the power supply in the particular amplifier or other component. The more ideal the power supply, and the better its ability to store and deliver energy to cope with transient peaks, the less the difference the fuse figures to make.

3)Similarly, the narrower the dynamic range of the music you tend to listen to, the less difference the fuse figures to make, imo.

Regards,
-- Al

Way back when, Peter Aczel from the Audio Critic(before the 10 great audio lies)in about 1980,he suggested that speakers which has fuses, actually sounded better if you bypassed them altogether.
So chalk one up for those who feel fuses do have an influence on sound.
I stuck with this mindset and replaced the speaker protection fuses in some of my amps also.

Keep in mind, though, that fuses in speakers, and speaker protection fuses in amps, are directly in the signal path, while ac line fuses are not. Also, the current that is conducted through speaker and power amplifier fuses is both large and fluctuating, while the currents that are conducted through the ac line fuses of line level and source components are small and relatively constant. Different situations altogether.

Regards,
-- Al