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Direction of aftermarket fuses (only for believers!)

It is with reluctance that I start another thread on this topic with the ONLY GOAL for believers to share their experience about aftermarket fuses.
To others: you can call us snobs, emperors w/o clothes,... etc but I hope you refrain posting just your opinion here. If you did not hear any difference, great, maybe there isn’t.

The main driver for this new post is that I am starting a project to mod my NAD M25 7 ch amp for my home theater. It has 19 fuses (2 per channel, 4 on the power supply board, 1 main AC) and I will try a mix of AMR Gold, SR Black and Audio Magic Platinum (anyway that is the plan, I may try out some other brands/models). As it is reasonably difficult to change them, esp the ones on each channel module that requires complete disassembly, I would like to know what the direction is for these models mentioned and of course, others who HAVE HEARD there is a difference please share your experience on any fuse model you have tried.

Fuses are IME directional:
Isoclean is one of the first to indicate the direction (2008/2009) on their fuses. Users of HiFi Tuning (when the awareness rose quite a bit amongst audiophiles) have mostly heard the difference.

As an IEEE engineer, I was highly skeptical of cabling decades ago (I like the speaker design of John Dunlavy but he said on many occasions that cables nor footers matter at all, WRONG!). Luckily, my curiosity proved me wrong as well. I see the same skepticism that I and many others had about the need for aftermarket cables many, many years ago now on fuses and esp on the direction on fuses.

Another example is the direction of capacitors (I do not mean electrolytic types). Even some manufacturers now and certainly many in the past did not believe it can make a difference sonically. Maybe some do but it takes time in the assembly to sort and put them in the right direction/order (esp as some of the cap manufacturers still do not indicate "polarity") so that maybe is one argument why this is not universally implemented.








128x128jazzonthehudson
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almarg
9,670 posts
 
Atmasphere 5-27-2016 12:57 pm EDT
I was not at any time suggesting that the holder was directional.
Yes, that was very clear in your post, Ralph.  It was also clear to me that Geoff's response represented a complete misreading of what you said.

Jea48 5-27-2016 9:17 am EDT
Your explanation makes more sense, at least to me, that the directionality of the fuse has to do with a VD, voltage drop, across the fuse element itself. That assumes the VD across the fuse would be measured in millivolts.
Jim, I believe that you inadvertently omitted the word "than" in the first line quoted above, and that you were intending to say:
Your explanation makes more sense, at least to me, THAN that the directionality of the fuse has to do with a VD, voltage drop, across the fuse element itself. That assumes the VD across the fuse would be measured in millivolts.
I wouldn't normally point out a seemingly minor omission like that, but with that word not included it took me a while to interpret your comment (with which I of course agree).

Best regards,
-- Al
 
gs5556
1,234 posts
 
Took a look at hi-fi tuning measurements and they are meaningless. The data presented indicates the measuring instrument has a resolution of 0.001 milli ohm. The readings shows an average of 40 micro ohm difference in each direction.

That is the proof of directionality? Hardly. If the ambient air temperature should rise by 0.1 degree C as you change the probes around, that would be enough to close the difference to 10 micro ohms. Not to mention that the surfaces of the fuse contacts must be accurately milled for those readings to occur everywhere around the fuse. Not to mention the fuse elements have to be cut to the precise length and diameter each time.

If you hear a difference in one direction over another, you get no argument from me. But don't show me numbers and say this proves it.

jea48
4,425 posts
 

atmaspere said:

Its more than just millivolts- I can measure the effects with a 3 1/2 digit voltmeter. Mitch2’s suggestion by the way is excellent and is also measurable. Some fuseholders (like panel mount units) won’t allow this.

In response to my post:

Millivolts...... If that was the reason, wouldn’t the same reasoning hold true for the AC mains line voltage feeding the fuse? In other words a small VD in millivolts on the mains feeding a piece of equipment could/would have an impact on the SQ of the piece of equipment. Not hardly....

Your explanation makes more sense, at least to me, that the directionality of the fuse has to do with a VD, voltage drop, across the fuse element itself. That assumes the VD across the fuse would be measured in millivolts.

Millivolts...... If that was the reason, wouldn’t the same reasoning hold true for the AC mains line voltage feeding the fuse? In other words a small VD in millivolts on the mains feeding a piece of equipment could/would have an impact on the SQ of the piece of equipment. Not hardly....

Sorry if I was not clear. The resistance I was referring to is that of the fuse element itself inside the fuse. Not the resistance that can be created from a poor fuse to fuse clip connection due to corrosion and or poor contact pressure.

Jim

jea48
4,425 posts
 

Hi Al,

Just read your post. I should have done a better job of what I was trying to say. After reading your post, I can see why Ralph took it the wrong way.


geoffkait's avatar
geoffkait
23,365 posts
 
Atmasphere wrote,

"Occam’s Razor has something to say here! Given that a fuse has to be used in AC circuits and given that people report differences by reversing the fuse, and also understanding how fuses are inherently incapable of having directionality in any way whatsoever, the explanation that they somehow have an effect by reversing them in the holder is a fairly complex explanation: some sort of unknowable, unmeasurable quality of the fuse itself."

i actually wouldn't be quite so hasty to dismiss fuse directionality out of hand. Let me give you exhibit A, interconnects. A certain kind of interconnect, one without a shield. The keen eared listener will discover that interconnects are directional, too. Just like fuses. Just like any metal wire conductor. This is precisely why many cable manufacturers mark their cables, the unshielded cables, with arrows, so that the cables are connected on the correct direction. Anti Cables marks their cables and they are just copper with lacquer covering. Audioquest and others mark their cables as well. Obviously some companies mark their cables with arrows only for the purposes of the shield.  If you have interconnects that don't have shields it's worth reversing them and seeing if that sounds better. I suspect this is true for both solid core and stranded. Speaking of which, the only way fuses or wire wouldn't be directional is if the conductor was some amorphous material like carbon or even lead, just for example, you know, non crystalline.

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