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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
nonoise's avatar
nonoise
4,382 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
8,673 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
4,382 posts
 
Thanks Jazz and Al,
So much for that avenue of thought. :-)
geoffkait's avatar
geoffkait
14,147 posts
 

jazzonthehudson OP
254 posts
05-23-2016 8:23pm
"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."

Right, and the use of paste type contact enhancers such as Quicksilver Gold (pure silver spiked with gold) ensures a consistent and thorough contact of the fuse end caps with the fuse holder. And guess what? The fuses are still directional. Is this a good time to mention the elephant in the room - wire directionality? Not just fuse directionality, but directionality of interconnects, speaker cables, the wire in transformers, the wire in capacitors, internal wiring in electronics, the wiring in speakers and speaker crossovers, you name it. And power cords - even though they are in an AC circuit. Perhaps even RCA connectors and other stamped, rolled or drawn metal used in electonics. Maybe even fuse holders, though not for the reason suggested yesterday.

cheers,

geoff kait
machina dynamica

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