Determining current flow to install "audiophile" fuses.

Well, I was the first to answer the OP and said I couldn't think of why a fuse could be directional.
Since then, I called McCormack (I own a DNA-1)and spoke at length with Pat, who said that I should try the fuses in both directions and see if there is a difference. (He did think there is a difference)..
I bought the last few Hifi Tuning Star Sapphires still available for the Power Mains.
To me, yes, there was a difference in sound, a significant change, mostly for the better.
So, after a few days, I will try reversing the fuse and will post my observations.
No, it won't be a scientific test, but I consider my audio system a pleasure/hobby.- Though it would be nice if there were a scientific explanation. 
My only gripe is that many of these companies are upgrading their fuses, AND then increasing prices to somewhat unreasonable amounts.-Perhaps that should go on another thread....

Excerpt from the introduction of Zen and the Art of Debunkery:

"As the millennium turns, science seems in many ways to be treading the weary path of the religions it presumed to replace. Where free, dispassionate inquiry once reigned, emotions now run high in the defense of a fundamentalized "scientific truth." As anomalies mount up beneath a sea of denial, defenders of the Faith and the Kingdom cling with increasing self-righteousness to the hull of a sinking paradigm. Faced with provocative evidence of things undreamt of in their philosophy, many otherwise mature scientists revert to a kind of skeptical infantilism characterized by blind faith in the absoluteness of the familiar. Small wonder, then, that so many promising fields of inquiry remain shrouded in superstition, ignorance, denial, disinformation, taboo . . . and debunkery.

• Put on the right face. Cultivate a condescending air certifying that your personal opinions are backed by the full faith and credit of God. Adopting a disdainful, upper-class manner is optional but highly recommended.

• Employ vague, subjective, dismissive terms such as "ridiculous," "trivial," "crackpot," or "bunk," in a manner that purports to carry the full force of scientific authority.

• Keep your arguments as abstract and theoretical as possible. This will send the message that accepted theory overrides any actual evidence that might challenge it -- and that therefore no such evidence is worth examining.

• By every indirect means at your disposal imply that science is powerless to police itself against fraud and misperception, and that only self-appointed vigilantism can save it from itself.

• Portray science not as an open-ended process of discovery but as a pre-emptive holy war against invading hordes of quackery-spouting infidels. Since in war the ends justify the means, you may fudge, stretch or violate the scientific method, or even omit it entirely, in the name of defending it.

• Reinforce the popular fiction that our scientific knowledge is complete and finished. Do this by asserting that "if such-and-such discovery were legitimate, then surely we would already know about it!"

• Deny the possibility of phenomena for which no plausible explanations have been advanced. Ignore such contrary examples as the existence of disease prior to the discovery of microbes, the sun's copious production of energy long before the discovery of nuclear fusion, and the stubborn persistence of gravity despite our stubborn ignorance of its inner workings."

cheers, 

geoff kait

Gents,
I stuck my neck into the "Red Fuse" debate recently and it found it fruitless. This fuse "direction" debate is even more absurd. Lots of educated folks propound evidence that it is BS with AC current. All smart guys know that to be the case. Others, perhaps with an expectational bias, hear it differently and good for them and the boutique fuse marketers.

The point of my post to my erudite friends hereon, from whom I have leaned plenty (you know who you are) is that engaging GK in a rational argument about electrical circuit behavior is a fool's errand, just tiltin’ at windmills. You are trying to engage in a logical, rational discussion with him and it is impossible. He is on a different wave-length in all manner of his perception of reality and clearly loves to pull everybody’s chain who is thinking about anything that makes any sort of sense. I am scornful of his often successful attempts at making thoughtful and helpful posters take their eye off the ball, which is our enjoyment of music and the gear to do with, to engage in his ridiculously inane assertions. My best advice is not to engage the fellow as it is less productive than dealing with a petulant two-year old child who is having a "bad hair" day.  The big picture is that in the audio world, GK is as insignificant as the atoms he sees floating around on the surface of conductors.  I pity him as he brings nothing but vitriol to these discussions. We are all bigger than that. Cheers lads, Whitestix

Bdp24 wrote,

"To make sense, the maker of fuses claimed to be directional would have to have either:

1- Manufactured the wire used in his fuses (having control over the manufacturing would facilitate him keeping track of the directional properties of that wire. Do any of the audiophile fuse makers claim to manufacture the wire they use in their fuses?)"

Excellent, excellent! Did you just take some smart pills or something? Of course the fuse manufacturer would have to keep track of the wire in terms of the correct direction and ensure that the correct direction is maintained throughout the whole manufacturing process. It sounds complicated but it’s actually not and fuse manufacturers - just like cable manufacturers - have been doing just that twenty years. Hel-looo! PS the fuse manufacturers don’t actually have to manufacture the wire. All they would have to do is check for directionality when the big spool of wire arrives. Then the directionality of the wire for the rest of the entire spool is known. Of course, some fuse manufacturers might produce their own wire, who knows? But it wouldn’t matter, the methodology would be the same.