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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
geoffkait's avatar
geoffkait
23,365 posts
 
Just to comment that the way I read the voltage drops is not at all like some other folks, I.e., the naysayers. Here’s how I read them. The differences in voltage drops are not responsible for the differences in sound, they are intended to be only a clue that something is going on. If a fuse was electrically symmetrical wouldn't it measure exactly the same one way as the other? The fact is even the independent tester commented that the voltage drop differences don't correlate with the sonic differences heard in fuse directionality listening tests. I suspect if someone, and I’m not mentioning any names, were to measure *distortion* in the fuse or say *noise* then we might see some more uh convincing differences between fuse directions, not to mention between cryo’d and uncryo’d fuses. Therefore, I wouldn’t get too hung up on the obviously slight differences in voltage drops.

cheerio
mapman's avatar
mapman
22,183 posts
 
Yawn. 
geoffkait's avatar
geoffkait
23,365 posts
 

mapman
13,349 posts
05-27-2016 4:36pm
Yawn.

No. 13,349. Thanks for your input.  Are we keeping you up past your bedtime?
mapman's avatar
mapman
22,183 posts
 
You'd think but no.  🏄
jazzonthehudson's avatar
jazzonthehudson OP
277 posts
 
Jim, thanks for the extract from John Curl! From the electrical point of view, a VD should not matter much. Your comments was also incorrectly interpreted by me ( Al, thanks for the small but important addition of "THAN" ), hence my thought of possibly testing same brand fuses with different breaking points/capacities.

My best guess is that the vibration control/dampening (e.g. use of special liquids, beeswax, dampening material in Bussman) is a very important determinant, as well as the metallurgical composition and treatment (cryo) of fuse / fuse filaments. 


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