Fuses fuses fuses

Charles, a hundred years of experimental psychology has evolved very strong paradigms for dealing with experimenter bias, subject bias, and confounding factors. It is easy for those with expertise in engineering or mathematics to dismiss these advances, but that would be a mistake. The experimental tools are there.

These tools can be used to demonstrate heretofore unsuspected effects. Doing so is good for careers. The absence of an effect which can be repeated in the lab is evidence against the existence of that effect. Not proof. Just evidence.

I find Ralph's explanation of the phenomenon to be convincing. And it would be very easy to test. Anyone who wanted to bother only needs to repeat the experiment many times with randomization, and count. I suggest a paradigm known as 'two alternative forced choice'. Elementary statistics would do the rest.

As I said before, there's lots of places to park money in this hobby, lots of places where everyone agrees. That's where I spend money.

Terry9
I found Ralph’s explanation of the phenomenon to be convincing. And it would be very easy to test. Anyone who wanted to bother only needs to repeat the experiment many times with randomization, and count. I suggest a paradigm known as ’two alternative forced choice’. Elementary statistics would do the rest.

OK, so if it would be "very easy to test" how come none of you guys ever bother to test it? Talk is cheap. And if it takes a test to prove directionality how come you guys have made up your minds already? Who do you think is going to test it, NASA? Besides I’ve got a sneaking suspicion you guys would not believe or would find fault with any test and or test results presented to you, as long as the results were not in accordance with your preconceived notions of time and space - Just as you guys have with the test results of fuse directionality found in the data sheets on the HiFi Tuning website. Yeah, I know what you’re thinking, what test results? Right? You guys always seem to find some little nit to pick when the results don’t comport with your preconceived worldview. East is east and west is west and never the twain shall meet.

"East is east and west is west and never the twain shall meet" Geoff, well stated and true. Terry9 I can tell you that the upgrade fuses are clearly effective in my system. However you’d likely remain skeptical based on your own inherent bias and preformed opinion. I understand that and it’s okay with me. East vs west 😊. I will agree with you regarding spending money where you believe it’s appropriate and justified. That’s what I did and am very pleased. This criteria will naturally vary amongst us all. If we're both satisfied with our respective audio systems, all is good in the final analysis. 
Charles

I'm not one who frequents these forums often, but I do reflect my observations and results that work with my system. It seems the same parties are always contraversial and negative without being objective. Being trained as an engineer, I've always kept an open mind and made my evaluations after many attempts in order to come to decision.

I use the same procedures for evaluating equipment and tweaks in the 40+ years of being a music ethusiast. Concerning fuses, I tried at various occasions reversing the direction on all my equipment one at a time. I also reversed the order so I wouldn't be sucked into the placebo effect. As a result I did hear some differences when the fuses were reversed. I tried not to look at the position/ direction of the fuse but always came back to the same results even weeks later.

I also did the same tests with various fuses. I tried fuses from HiFi Tuning, Synergistic Red and Black and Audio Horizons on different occasions and directions. The Audio Horizons worked best for my system, but that's my opinion. What is interesting, the stock fuse worked best in my previously owned PS Audio P3 power condition.

So what I'm stating is be opened minded and evaluate for yourself. Every system is different and so are our ears. Just enjoy the music............

First, to be sure it’s clear, the point of contention in this thread does not concern the efficacy of fuse upgrades. It concerns the OP’s question no. 3, regarding fuse directionality. And in that regard there appears to be a reasonably compelling body of anecdotal evidence, especially in the long-running Synergistic Red Fuse thread, that changing the direction of a fuse can make a difference, even if it is an AC mains fuse.

However, the problem is that establishing that changing the direction of a fuse makes a difference does not establish that a fuse is inherently directional, as many seem to automatically assume. One does not necessarily follow from the other, especially given Ralph’s empirical findings that I cited above (which he reported to be both measurable and audible), and also given that in the opinion of many of those having an extensive background in electronic design there is no means by which that is possible. As I put it in my post in the Synergistic Red Fuse thread that I referred to earlier:

[Inherent directionality in fuses] is fundamentally irreconcilable with any reasonable understanding of how electronic circuits work. Which is not to say, of course, that an understanding of how electronic circuits work can explain or predict everything about what we hear or don’t hear from our systems. It certainly can’t. But it can often help to provide a perspective on what does or does not have a reasonable possibility of being audibly significant.... And again, none of this is to say that I doubt the accuracy of most of the reported perceptions, it just means that in cases where those perceptions are accurate I believe that the cause was something else.

When the direction of a fuse is reversed all of the following variables, or at least potential variables, are being changed simultaneously:

1)Contact area.
2)Contact pressure.
3)Contact resistance.
4)Oxidation between the mating surfaces.
5)Warm-up state of the equipment.
6)Contents of "volatile" digital memory elements that may be present in the design (i.e., memory elements that don’t retain information when power is removed).
7)The states of other circuitry that may undergo re-initialization at turn-on.
8)Probably other variables that I haven’t thought of.
9)The direction of the element in the fuse.

In order to conclude and legitimately be able to claim that no. 9 is responsible for the difference that is heard, given especially what I and four different experienced designers of well regarded audio electronics have said in posts here which **strongly** point away from that possibility (again, see my post dated 10-28-2016 in the Synergistic Red Fuse thread), at the very least it is necessary to reverse and re-reverse the fuse multiple times, reinserting it each time with varying rotational orientation. To verify that the perceived difference is repeatable, and that it is not due to the phenomenon Ralph has reported, or to other variables.

And as I and Davehrab both said earlier, it appears that no one posting in any of the various fuse-related threads here who has claimed to have found that fuses are directional has done that. Which is understandable, given that significant time and effort would be required to do so with reasonable thoroughness. What is not understandable, though, to me at least, is failure to recognize that any of the other variables I listed may be responsible.

Regards,
-- Al