What direction should Hi Fi tune fuse be installed

The quote below is from a multi-part thread on the Polk Audio Forum entitled "Studies On Residential Power Line Noise - Part 7: HiFi Tuning and Isoclean Fuses".

"Both the HiFi Tuning and Isoclean fuses have arrows on their cases which indicate that they should be oriented in the direction of current (energy) flow. Some people have scoffed and ridiculed the idea of "directional" AC fuses. Rather than something to ridicule, I saw the arrows as indications that there was something going on inside the "fuses" that required a specific orientation. Initially, my ears told me that the fuses sounded better in the direction of the arrows than against it. Noise spectrum measurements with an oscilloscope verified that the line noise was lower in the direction of the arrows than against it."

So, it would appear, at least according to the author that fuse direction does have a measureable bearing on performance.

There are two points of interest, at least to me and some others, in the quoted review. First, there are differences in the resulting sound depending upon orientation. Okay, granted that's subjective. But what isn't in this hobby of ours? Second, there was less line noise when measured with the orientation of the fuse along current flow within the circuit.

I'm not trying to be argumentative here.

Al,

Thank you for taking the time to read through the article and raising the interesting points you do in your post. A technical person, I'm not. :)

That having been said, I do hear differences (a) when introducing after market fuses in the CD player, power amp, integrated amp and speakers that I've tried them in, and (b) when reversing the orientation of same. Why? Not a clue.

A question for you, if I may. You mention not knowing "how a fuse would have any "knowledge" of the direction in which energy is being transferred." Is it possible the fuse is constructed in such a way that it performs better one way than the other.

Just wondering.

Regards,
Joe

Al & Geoff,

My intention wasn't to stir a pot that's already messy.

The review thread I quoted from may have been less than rigorous in terms of design and the question of replication is ambiguous.

If the reader wishes, I recommend going through a research study done by GECOM Technologies GmbH that addresses such areas as resistance, noise, and voltage drops. The section on resistance shows measurements orienting the various fuses tested in both directions.

There are explanation and summary sections for the tests performed although the raw data and testing methodologies will be of interest to some, I'm sure.

Anyway, here's the link to the tests. Please note that you can download a PDF of the tests as well.

http://ultrasystem.com/usfeaturedprodsFUSE_LIT.html

Regards,
Joe

:)

Russe41,

Before speaking about wasting money, may I ask you a question, please? Ever tried after-market fuses in your system or have you just dismissed them out of hand?

The only person you're doing a disservice to is yourself.