How it works! From a common man.

The longer we listen to something, the more we mask out what we do not like, and focus on what we do like.  This is called "Break In", but it is our ears, not the equipment.  BTW,  AC current is "ALTERNATING back and forth.  I welcome an explanation of how a directional fuse would 1- work at all, 2- show a difference in  power going back and forth, and especially, this:  THREE!  Since our 110 volt system in the US has a neutral wire (tied to the ground) a plus 110 volt and a minus 110 vole, when combines give a difference potential of 220 volts, why would we not reverse the fuses if moving a system from one power outlet to another on the other leg (e.g. from a plus 110v to a minus 110v circuit).  I am serious.

noble100, Tim, don't give up dude!  One last tweak is all you need.  Try dipping a fuse in brown goop and biting down with it using the left side of your mouth and then do the same on the right side and compare the results.  This will take hours to do properly.  Keep a log of every perception real and imagined then repeat with two fuses, one on each side of your mouth.  The next step is crucial.  You must put a cpap mask on (like the one oldhvymec uses) and stand upright looking down at your speakers.  Oh yea, the brown goop needs to be applied to the cpap mask as well. 

Your welcome.   

It's 120 Vac, and not 110 for quite a while. A lot of the same people that quote what they have learned, seem to forget APPLIED sometimes thing aren't what they seem. I worked on heavy equipment for 45 years. Mainly VDC. You think I cared about the direction of the fuse. I worked on gen sets, BOTH DC (transport side) AC the work side.. I just wanted the right fuse. Direction?

This is my stereo. Not only can I hear the difference. It is a pretty significant. 4 other people sat in on the session, while  I blind sided them, with fuse swaps. I had one in a mono block left side, not the other side. 
2 weeks I let BOTH settle with their fuses, One orange SR. One busman.

I set up another pair of Class D with NO FUSES, inline.. removed. Silver wire, bridged the AC coming in, AROUND the fuse holder.

They had no memory of anything, I change gear every time they come over. 2 three times a year..

Thing about sound, you CAN talk yourself into hearing something or NOT, even worse.  

EX: It's fixed, I can't hear anything... AS it blows up... Time after time denial is even worse... I can hear EVERY little change vs, I can't discern the difference... Unfortunately, both are a pain for a guy like me...

ONLY the facts, not perceived, one way or the other is VERY rare indeed. We want it to sound "better" after all that work.. LOL

I'll also say "let me listen for a while" you can change your OWN mind if you look for a change. Looking and HEARING are two different things...

I'll concede, "better", not always, but different, very often..

Regards

I also understand AC goes back and forth, now ADD the rest.

Think of a ratchet, it moves both directions, (back and forth), BUT only advances in ONE direction. I know it's working because the meter spins ay! LOL It's not going back and forth. It spins backward, only when I put more in than I take out, Solar...

I like the Mr. Rodger approach, not the Nikola Tesla, though I admire the latter for his "NO LIMIT" thinking.

I don't know, I'm just a common man, AY

Regards