What is the science behind audiophile fuses?

My experience using Sluggo’s is that they are similar to tubes or cables. Each metal has it’s own sound signature. Copper warmer, silver more detailed and revealing, silver/rhodium hollow in between. But the graphene/copper slug was another “Oh My” moment and made the biggest improvement in SQ. Sluggos take many hours to break in and as crazy as this sounds some sound different if you switch their direction after break in. I am somewhat in Carlsbad2 camp where I only use the SDFB for my tube components with rectifiers. All other components with power input fuses I use sluggs without protection. I feel the very low risk of failure and the cost to repair the component is cheaper than buying more SDFB’s. I have never had a power input fuse blow just internal fuses protecting rectifier failures. Some are connecting a single SDFB to a splitter or outlet box and plug in multiple components with the same amp rating to avoid buying a SDFB’s for each component. Not sure of the science to it all but Sluggos do make a noticeable difference in SQ.

I like on many components that I don’t expect to fail, to just raw dog it with no protection and replace the fuse with a slug (some think this is crazy, they are entitled to their opinion).

Reading through this thread leaves me open to the possibility that line fuses, being essentially variable resistors, may have a discernable effect on sound quality. If so, the difference is likely to be confined to fuse vs. no fuse, such that replacing a Bussmann fuse with an "audiophile" fuse is likely to be of no import since the latter is still a variable resistor. So I would have to agree with @carlsbad2 's quote above.

The best way to achieve this, though, is not to install slugs of various metals that can’t possibly make any audible difference, insofar as they are cradled in uber-cheap fuse holders made of common steel. Desoldering and tossing that 10 cent fuse holder and jumpering a length of appropriate gauge wire in its place, thus essentially hardwiring your power cord to your equipment's PCB as @mitch2 suggested, seems the sensible way to go.

As far as the Swiss Digital Fuse Box, it answers the safety question, but it seems highly unlikely that any device sitting inline with your power cord AND needing a 2nd power cord in order to function would not impart its own sound signature onto your system, just like power cords themselves have their own sound signatures.

Can the Swiss Digital Fuse Box be truly neutral sounding, or is swapping it for a fuse a case of robbing Peter to pay Paul, so to speak?

How about magnetic breakers, can they be free of effects on sound quality?

It is of course easy to take the fuse thing to absurd extremes that attract scorn and ridicule, but there is a sound case to be made for eliminating them - in a way that ensures safeguards remain intact of course, or are even improved. Fuses are not that good at doing their jobs anyway, so it is interesting to read about what can be done to improve upon the current situation.

@devinplombier I agree with most of your thoughts above. I assume by "variable" resistor, you mean that it changes depending on what current rating it is.  

I will explain that the SDFB is basicly a relay with a magnetic current switch to open it (thus, the same as a magnaetic breaker).  So when closed, it is just a pair of contacts in line with the power. So if a good relay, with high power handling and good contacts with essentially zero resistance is chosen, it should be just about like a straight wire.

If you can find a magnetic breaker to put in the line I'd like to see it.  I couldn't find one that would work.

Jerry

@carlsbad2 

We are on the same page. Electrically, a closed relay is definitely equivalent to a straight wire.

So are power cords, but folks still heatedly argue about them.

If we accept that power cords - the essence of a straight wire - can have a sound signature, whether based on brand or copper purity or braiding style, it seems fair to assume that a more complex device inline with a power cord might also introduce its own sound signature.

Re magnetic breakers, I was just following along with @mitch2 's comment:

I am going to receive two of them (10A) that I plan to use for a solution external to the amp chassis, but that will not require an extra power cord like the SDFB.

I for one am curious to find out how his experiment turns out

Let's assume for a moment that we know what the "filler" is in an Audiomagic M2 fuse. Some rumor that it is graphene loaded beeswax.

Can anyone here scientifically speculate about the effects thereof? I know how the fuse sounds, but how would it be achieving that sound and why would that sound be different from a bare fuse wire?