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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
atmasphere's avatar
atmasphere
11,793 posts
 
Therefore, going by Occum's razor as Atmasphere suggests, the hypothesis with the fewest assumptions would be that the fuse itself is directional, not the fuse holder.
This is a classic strawman, and like all logical fallacies, is false by definition. I was not at any time suggesting that the holder was directional.

 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....

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.
almarg's avatar
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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.


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