What direction should Hi Fi tune fuse be installed

05-13-14: Joe_appierto
Is it possible the fuse is constructed in such a way that it performs better one way than the other.

That of course goes to the heart of the debate, Joe. From a technical standpoint I cannot envision any mechanism by which that could occur. As you may have seen in reading through the thread, though, my instinct has been to not question the perceptions of those who report hearing differences (although I certainly would not rule out the possibility of flawed perception in all cases). Given the lack of technical plausibility, it seems to me that the most probable explanation is that reported differences are generally due to unrecognized extraneous variables. The leading candidate perhaps being differences in contact integrity as the two orientations are tried. Perhaps also differences in equipment warmup state, and fluctuations in AC line voltage or noise conditions.

Which is why I have emphasized the desirability of performing comparisons while going back and forth between the two orientations several times, before drawing any conclusions.

Best regards,
-- Al

Al and Mapman, I don't mean to put your feet to the fire, but could either one of you kindly post a quote from an aftermarket fuse manufacturer, any manufacturer, where he states that "the fuse arrow is supposed to be in the direction of current flow." I'm pretty sure this whole "in the direction of current flow" is just something that naysayers, in lockstep, picked up on after it was repeated a thousand times on the Internet. Kinda like Morphic Resonance, the hundred monkeys thing. It's called a Strawman Argument. Hel-loo!

Geoff, I have not asserted that the fuse manufacturers assert that their fuses should be oriented in the direction of "current flow." As you say, that might simply be something that has been "repeated a thousand times on the internet," though not particularly by the naysayers. Just take a look at the early posts in this thread, or at the statement in the paper Joe referenced that "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."

What I have maintained is that the various explanations and measurements that have been offered as rationale for fuse directionality are flawed, and that IMO the explanation of reported differences that has the greatest probability of being correct is failure to recognize and control extraneous variables.

Regards,
-- Al

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

Thanks, Joe. It so happens that I had provided my comments regarding that paper in another fuse-related thread, about two years ago.

Best regards,
-- Al