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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
atmasphere's avatar
atmasphere
12,138 posts
 
^^ Arcing is often audible with audio equipment. An arcing power switch can make quite a racket!

If you have arcing in an older house wiring system, failure of the arcing component (wall socket or the like) is eminent. It can also be a fire hazard.

Any connection has a certain amount of resistance. As current flows through it the resistance causes heat. A cold solderjoint will heat up faster than a proper solderjoint.

When a fuse blows, it will be warm or hot if you remove it at the time of failure. Its heat that blows a fuse. So it should be no surprise that any fuse runs at a temperature and that there will be a voltage drop across it. Keeping the voltage drop to a minimum by optimizing the contacts helps the fuse as it will run cooler since the heat it makes is supposed to be made by its internal element not its contacts.  
jazzonthehudson's avatar
jazzonthehudson OP
277 posts
 
>> I’d like to hear from AC power cord designers/manufacturers. Do any of them test the wire they make their cords with for directionality? They can't simply be reversed by the user though, of course.

Some PC w/o shrink sleeves on plugs/IEC and thin threads like NordOst Valhalla can be tested, simply swap the ends. I may try that on my remaining Valhallas.

BTW, I am finally testing the fuse and their directions on my NAD M25 using PADIS fuses and report back if they are indeed the Furutech OEMs. 
atmasphere's avatar
atmasphere
12,138 posts
 
^^ Do you understand how power cords are wired? If you get it wrong, Bad Things happen!

BTW, the effects of a power cord are much easier to measure than that of fuses. I've seen a power cord rob an amplifier of about 1/3 of its total output power!
almarg's avatar
almarg
9,670 posts
 
Some PC w/o shrink sleeves on plugs/IEC and thin threads like NordOst Valhalla can be tested, simply swap the ends. I may try that on my remaining Valhallas.
Although if that is done and a difference is heard, it by no means proves that directionality of the wires is responsible. For example, the act of simply removing and reattaching the connectors would seem to me to have a greater chance of being responsible. Assuming, of course, that care has been taken to eliminate other possible extraneous variables, such as differences in warmup state (many here have asserted that days of warmup may be required for some solid state equipment to achieve optimum performance), or the re-initialization that occurs in some designs (especially those which include digital circuitry) when power is removed and re-applied, or even (as some members here have asserted in other threads) the act of physically manipulating the cord, allegedly necessitating significant time for it to "settle."

Best regards,
-- Al


geoffkait's avatar
geoffkait
23,365 posts
 

almarg
6,436 posts
06-08-2016 12:49pm
Some PC w/o shrink sleeves on plugs/IEC and thin threads like NordOst Valhalla can be tested, simply swap the ends. I may try that on my remaining Valhallas.
Although if that is done and a difference is heard, it by no means proves that directionality of the wires is responsible. For example, the act of simply removing and reattaching the connectors would seem to me to have a greater chance of being responsible. Assuming, of course, that care has been taken to eliminate other possible extraneous variables, such as differences in warmup state (many here have asserted that days of warmup may be required for some solid state equipment to achieve optimum performance), or the re-initialization that occurs in some designs (especially those which include digital circuitry) when power is removed and re-applied, or even (as some members here have asserted in other threads) the act of physically manipulating the cord, allegedly necessitating significant time for it to "settle.""

Of course, all of those "extraneous variables" you refer to can be controlled by the careful and thorough experimenter. There’s no reason to jump to conclusions. Looking on the bright side at least there’s no fuse holder to get in the way. Not sure I completely understand all the angst and concern over wire directionality since it rather easy to demonstrate it using stock fuses or unshielded interconnects. I can completely understand why uber skeptics would not wish to carry out these experiments themselves and report results. 

Cheers,

geoff kait
machina dynamica


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