Hi-Fi Tunig Fuses & Parasound A21

I have also found that the sound changes with the direction of the fuse. In one way it is relaxed with a very clear mid-range specially the voice with a little loose bass. The reverse direction produces a very fast, punchy sound with a controlled bass but it had a tad hazy mid-range specially the voice.. I wanted to get both but it is not possible at least with the current stock fuse.

This is not caused by reversal of the fuse but how it makes a connection. Quite often by reversing the fuse you get a better connection because the fuse sits better in its holder and thus there is a lower voltage drop across it.

IOW its the connection, not that its reversed. If the only way to get the fuse in the holder is by removing the fuse cap, you might not have much option but to reverse the fuse to see if the contact is better.

I don’t have an electrical engineering degree that might help inform me as to why things in this quizzical hobby happen as they do but they do occur. There is plenty of anecdotal evidence of such all over this site. Perhaps the mystery is part of the appeal.

Its the voltage drop across the fuse. You can hear it and measure it when the fuse is correct in its holder. Its easy to measure. If the fuse is on a circuit board, I find it more expedient to spin the fuse in its contacts until you see a lower voltage drop rather than reversing it.

The variable voltage drop caused by the fuses and fuse holders not being perfectly dimensioned is what has given rise to the idea that they are directional. They aren't (and can't be, if they were they could not be used in AC circuits); its just that sometimes when you reverse them you're getting a better connection. Its really that simple- no mystery and easy prove through measurement. If you want it to remain mysterious though, just don't measure the voltage drop across the fuse :)

@wolf_garcia  +1