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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.








jazzonthehudson
geoffkait's avatar
geoffkait
23,365 posts
 

atmasphere
4,816 posts
05-23-2016 6:07pm
Geoffkait: Al, if you (and Atmasphere) really were thorough you would simply eliminate the fuse holder entirely, no?

No. That would never meet UL, CE or other directives.

I meant if you wanted to get to the truth you would eliminate the fuse holder from the equation. You know, for the experiment. Capish? Whether or not aftermarket fuses meet UL, etc. is irrelevant to the question of directionality. You don’t really think audiophiles care if their fuses are UL listed, do you?

UL is a directive? You make it sound like a requirement. 

cheers

nonoise's avatar
nonoise
11,040 posts
 
Rotating the fuse in the fuse holder makes for an interesting point.

PADIS fuses don’t imprint on the side of the caps so the contact surface is constant and as complete as possible. Would the imprint on the side of the cap diminish the contact area enough to degrade the sound and could it be that by rotating or reversing the fuse has the potential to align things in the most desirable manner? There is enough space between the lettering on the cap sides to ensure better contact with other fuses.

Also, would this be akin to the "eddy effect" that connectors encounter?

All the best,Nonoise
jazzonthehudson's avatar
jazzonthehudson OP
277 posts
 
My experience tells me differently. Before I insert after market fuses, I clean the contacts - as all contacts - if they look clean, with Gold DeoxIT, otherwise first with silver polish, then DeoxIT. I always reverse back the direction to ensure my findings are consistent.
Whenever possible, double blind tests are conducted by wrapping Teflon around the fuses.
almarg's avatar
almarg
9,670 posts
 
Would the imprint on the side of the cap diminish the contact area enough to degrade the sound and could it be that by rotating or reversing the fuse has the potential to align things in the most desirable manner?
Hi Nonoise,

I suspect that the significance, if any, of the positioning of the imprint on the sonics of a component could only be determined experimentally. And I would expect that significance, if any, to certainly vary widely among components that perform different functions and that are different specific designs. Just as different designs will vary in their sensitivity to the much larger differences in line voltage that occur from location to location, and in many cases from time to time at a given location. The presence or absence of internal voltage regulation (most power amp designs have unregulated power supplies, in contrast to most line-level components), and the efficacy of that regulation if present, being just one of a great many design-related factors contributing to that variation.
Also, would this be akin to the "eddy effect" that connectors encounter?
What I am envisioning, and what I believe Ralph was referring to, are simply differences in the very small amounts of resistance that may exist between a fuse and the contacts on its holder. Not sure that eddy currents have relevance in this context.

Best regards,
-- Al

nonoise's avatar
nonoise
11,040 posts
 
Thanks Jazz and Al,
So much for that avenue of thought. :-)
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