Are all fuses created equal?


Does the quality of fuse vary for a given rating? I am asking the question in terms of the fuse's function not in terms of sonics. That is will some fuses provide better protection than others despite being the same type, say slow blow, and rated the same?
nick_sr
I blew all the rail fuses in my RB-1080 amp, but didn't know it. Put it into the shop, ListenUp in Denver, and they treated me right. Told me what was wrong, replaced the blown fuses and tighten everything up, tested it out, etc. I brought it home and it ran fine for about 3 months, then the rail fuses blew again. I replaced them with slow-blow fuses and have not experienced a blow-out since. That was 2 years ago. The RB-1080 blowing rail fuses is a known issue.
Some A'gon'rs have posted that replacing fast-blow fuses with slow-blow is risky for your speakers, because the amp is allowed to pump more current into them before the fuses blow, but I haven't had any problems.
Fuses are incorporated in the design of equipment to protect critical parts against excessive current. A blown fuse can result from abnormal electrical surges or from issues within the equipment itself. I would contact the manufacturer if I had equipment that was frequently blowing fuses.

Regarding the type of fuse, most of my amps have come with fast blow fuses. One amp designer told me, in their opinion, slow blow fuses were not "as linear" as fast blow fuses so they did not believe the slow blow fuses to be as good sonically.

Regarding quality, the past few years have seen several manufacturers using different (improved?) materials in their fuses, from gold end caps, to ceramic bodies, and even different metals such as silver or copper for the filament. I suspect the connection of the fuse to the circuit board could also have some effect on sonics. Some folks wrap teflon tape around the fuse or around the fuse and connection tabs to dampen resonances. Manufacturers of "high end" fuses include HiFi Tuning, Isoclean, Furutech, PS Audio and others. As an example, the PS Audio "Critical Link" fuse offers the following;
Direct gold plated end caps
OFC copper end caps
OFC copper fuse element
Foam damping inside
Cryogenically treated
One amplifier designer/manufacturer I know has high regard for the Furutech fuses on a sonic basis, and uses them in amps and preamps, even though they only come in a slow blow type. Another rather large manufacturer of high end gear told me within the past year they had not yet concluded how to approach aftermarket fuses with regard to equipment repair and warranty, and they had some concern that not all the aftermarket fuses were properly constructed from the standpoint of protection of the equipment. I found that an interesting comment.
Fuses from the main manufacturers are pretty standard.
The 'audiophile' ones may or may not be correct for the use they are put to.
No one knows if the aftermarket audiophile fuses are actually tested for all the parameters normally used for a specific fuse rating.
So, it is a crapshoot IMO. for audiophile fuses.
The point of a fuse is to protect the equipment in an accident. If one wants to play around and get better sound at the risk of damaging the equipment.. That is their right to do so.

So for the OP question: IF the fuse is a common commercially made fuse, they should be all the same, in all measured characteristics.
IF it is an aftermarket 'audiophile fuse' then no, all bets are off. the fuse may be very different in behavoir from one maker to the next. And for warranty, I would think some manufactures would not cover warranty if aftermarket fuses are installed in critical appications.

(For myself, I use audiophile fuses in the direct signal path in my Magnepan speakers, but standard commercial ones for all power supplies. I do not trust audiophile fuses to be the correct ones for critical applications like in an amplifier.
in terms of sonics yes they're all equal.
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