What are fuses used for?

I have, I’m sure to many, a very dumb question. I keep reading about fuses.  I have a fairly sophisticated system and have never come across the need for a fuse.
Can someone tell me where these fuses go and what they’re used for?
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They are used to prevent damage to electric circuits from excess current. A fuse is a fine piece of wire with a selected melting point placed in series with one leg of the incoming AC voltage/current. If an electronic device draws too much current the fuse wire will melt and open. Preventing any AC voltage/current from entering the device. Thereby saving the device/circuit from further damage.
All electronic devices/circuits require fuses at the inputs to the power supplies. The exception being battery (DC) powered devices where maximum current draw is limited by the battery size.
Contrary to popular misconception by the ill-informed fuses (like all wire) have NO effect upon sound quality. To think otherwise is to believe in magic!
Fuses can be used to change or control the sound just like speaker cables, interconnects, capacitors, power cords or any wire or cable. Capacitors serve a function just like fuses. Yet capacitors are also directional due to the wire running through them. Since all wire is directional, including the teeny tiny fuse element, all cables, capacitors, fuses sound better in one direction vs the other direction. In one direction, that usually cannot be predicted by the user, the sound will be relatively more coherent, more natural and more musical than the other direction.

This proposition regarding directional can be illustrated most easily by reversing the direction of interconnects and evaluating which direction sounds better. Voila! I’m not referring to shielded interconnects, since they have their own independent issue regarding direction.
I almost forgot. Fuses are also used to torture naysayers. That’s the most fun feature of fuses as we have seen.  Fun for everyone! 
“Contrary to popular misconception by the ill-informed fuses (like all wire) have NO effect upon sound quality. To think otherwise is to believe in magic!”

Here we go again.....hope this thread doesn’t turn into heated debate on the effectiveness of aftermarket vs. stock fuses. 
Where do you put the fuse????
If you have the manuals for your equipment it shows you where to replace a fuse. If you don't have the manuals you can probably download them from the manufacturer. 
Look on the back panel. Near the AC cord/outlet you will see a round (usually) screw-type cap. Below it will be a designation indicating the size of the fuse required. Unscrew the cap and pull it out. The fuse is held at one end by the cap. It is a press fit. Pull on the fuse to remove it. Hold the fuse up to a light and observe the very thin wire within. If it is intact the fuse is good. If the wire is broken the fuse needs replacement. Replace only with a fuse of the same rating on the back panel.
Some fuse holders are square and require a push-in for release. Others are round and require a push-in with a twist before they can be pulled out.
After trying a few different brands of high end fuses on my McIntosh C2500 tube pre I have come to the conclusion that there are better ways to spend the money (like giving it to the homeless).  Either my system has such high resolution that they aren’t needed (doubtful), or it’s snake oil.  I go with snake oil.  
I tested some "premium" fuses a while back after disputing the insane hyperbole attached to them by a few shameless salespeople...I figured it would be interesting and I had access to a pile of 'em...I found them to be absolutely useless relative to SQ, and some were actually rated improperly and blew in a power amp. 
OK, Wolfie, I’ll give you that - they didn’t work for you. So it’s what, you against 40,000? The smart money is on the 40,000, not some pro audio layabout. 
Why the put downs? If he heard nothing so what. It is his money and his experience. If you heard a huge improvement then good for you. Leave it there. 
Whoa! What? Why the put downs? Hey, phillyb, no offense but I’m afraid you’re not following. Wolfie is claiming everyone who hears the fuse is crazy. And he’s the only sane one because he can’t hear the fuse. Capish? If that ain’t a freakin Catch 22 I don’t know what is!
After trying a few different brands of fuses I heard amazing differences between them all. I thought people would like to hear what I experienced, then I read the thread on fuses and realized I was wrong.
Oh. I should have said that I really don't care what other people think about that. It matters what I think when I am listening to my system. Good thing too because it would be weird if I had to ask what somebody else heard, while I am listening to my system, to enjoy my system.
Sounds like marqmike is in my group, the group where we don't give a rats what anybody else thinks or says.
It's our money, our system, our ears and to infinity and beyond for the rest of you.
Everyone should decide for themselves what sounds best in their system. Leaving it to others is like doing art, by committee. The final result won't please anyone.

All the best,
roberjerman, fuses can have a dramatic affect on sound quality.  i just recently replace the fuse in my Parasound Halo Integrated, and it made more difference than any upgrade to my system in fifty years.  To think they can't improve (or sometimes degrade sound?) is to be blind and naive. Because of the improvement I heard, I replaced the fuse in my Cocktail Audio X45 Pro.  Although not as dramatic of an improvement, it still was very noticeable. 
Fuses are used to prop up the egos of some super human beings on this site who pretend they can hear the difference they make to the sound :-)

In the real world however, they will be very thoroughly investigated by your insurance company if and when you have a fire which may be caused by faulty equipment.

Playing the old fear angle, eh.
@phillyb asked:
Why the put downs? If he heard nothing so what. It is his money and his experience. If you heard a huge improvement then good for you. Leave it there.
You have to know the motives of Geoffy the fuse troll. He is all about defending his science fiction fuse empire, and his feeble attempts to try to make fun of legit members is how he does it. 
So, do different fuses work better for different genres of music? What fuse should I get for Rock? Blues? Jazz?

Is the same fuse (brand/series, I know I will need different ratings) best for all equipment, or will I need to try various combinations for all equipment (turntable, pre-amp, amp, cd player, speakers)?

Is there a fuse that I can swap out in my remote control, if so how important is that to sound quality?

You catch on pretty quick...I would start with remote control. Please report back which button on your remote control now allows you to hear the subtle nuances (previously inaudible) with Rock, Blues and Jazz music 😉

For best performance listen to the fuse one way, and then reverse the other way to determine best sonic orientation.
Thats a tough one ill try to figure it out get back to you asap.
It is also possible if you have newer gear there maybe NO "user" accessible fuse to change.
There has been a trend to just solder a fuse internally on a board.

Obviously not something you can just switch out quickly and easily.

Some even more enlightened manufacturers have abandoned fuses altogether in favour of circuit breakers.
I think I’m going to be a flatearther on this one.
It seems like too much trouble.

I appreciate your candidness and respect the decision.

I removed the fuse from my amp and shook a magic chicken foot at it.  It started to smoke and from beneath the smoke rose a black mamba.  The black mamba was thick and long with bolts of lightning jetting from its tip.  My buddies wife wrestled that mamba for hours, and after that night he said she was never the same.
Probably a very wise decision... Lol.
One more item not to fret over or spend money on!
Some crafty manufacturers found that by claiming a lot of nonsense about Special fuses made with beeswax or silly pseudo science, with very little rational explanation of why they could make this magic: "New UEF Graphene coating, two years in development, and UEF quantum treatments make the BLUE fuse significantly more holographic and dynamic than even the incredible SR BLACK fuse. Resolution and musicality are second to none"...like that...would make some easy tweak bucks...that’s pretty much it. If 40,000 hopeful and faithful bought in, as says Kaitty, that’s just sad and likely inaccurate, but far more than 40,000 HAVEN’T bought in (they perhaps haven’t heard about the astonishing benefits of fuse "upgrades"). For weird reasons better explained by non-layabouts, Conference Call Kaitty has issues with the fact that I actually did a pretty thorough test, and am a successful (admittedly frequently overpaid) live concert sound engineer...likely more fun than being an imagined Audio Insider.
Wolf, we all know acoustic engineering school is a scam. They don’t teach anything to prepare you for high end audio. They don’t even teach engineering. Give me a break. They teach you how to be a knob turner and wire puller. Though, on the plus side, being all thumbs might actually be good for knob turning. You should run down with great haste to whatever two-year podunk school you went to and demand your money back. No offense.
No offense taken there Kaitty as my skills come from over 5 decades of on the job experience as a working musician with no time for whatever Acoustic Engineering School might offer. My experience of working with those having been "trained" varies from smart and talented people to those with zero aptitude or talent. Ya never know. I get these live sound gigs from reputation only...sorry Kaitty...I know this bothers you, and my interest in audio has also been due to many years of practical experience, although it's only been during the last 30 years or so that I've been able to afford the gear I want, and focus on hifi instead of the musician gear needed to play live constantly as well as do personal and commercial recording work. As an aside...in the fourth grade I was trained by somebody in the audio-video department of my elementary school to run the 16 millimeter projector for a teacher with severe "projector phobia"...they'd take me out of my class from time to time and off I'd go to wheel a projector set into her classroom, which I thought was GREAT. That's where that stuff started I suppose.
What I glean from your post is that fourth grade was a watershed year in your development. 👦
@ geoffkait1

I worked with several Acoustical Engineers (some PhDs) in the past, their coursework all expanded on Mechanical Engineering as this is how acoustics is best modeled. Just a plain old BSEE here.
Oh, they got their PhD in two years? Wow! They must have very large heads.
Who said anything about two years?
Three guesses. The first two don’t count.
I highly recommend a fuse selector/switch to facilitate a convenient change for different genres of music. This could likely be automated with an interface to the music source.  You would then use the program that someone else wrote to automate you fuse selections.
With all the worry about which fuse now set aside, you could now enjoy your music without needing to think about the fuse.  Unless, you wanted to account, of course, for time of day, phases of the moon, temperature, etc.  I am sure that, for a small fee, updates would be available for every eventuality.  However, the improvement realized in SQ would be worth every penny.
Oh boy !! And so it continues ................
Did somebody forget to set out the roach motels last over the holiday? 🏨
"Yet capacitors are also directional due to the wire running through them."
What is the definition of "wire" for this purpose? Surely not what first comes to one's mind.
"...we all know acoustic engineering school is a scam. They don’t teach anything to prepare you for high end audio."

Do not skip the school altogether. Apparently, more info about high-end audio education is here...


Glubson, just curious, did you forget to take your smart pills this morning?
Could a fuse make a difference? I doubt it, but there's good ways to tell.

Put an oscilloscope on both ends of a fuse, ideally something with a frequency analyzier. Look at the scope.

When anyone provides visible proof of a fuse in anyway showing a voltage differential in real time between the input and output I'll be interested.

Now, that's not to say you could not do something cool, like have a fuse with a built in ferrite bead or something, which would reduce EMI / RFI. Would it be audible? See above. :)


Great idea. Why don’t you do it and report your findings? Are you waiting for someone else to do it?
I'm definitely not about to take work assigned by you, George.

I have no particular interest in fuses, I was merely pointing out that if audiophile fuses do anything at all the effects would be super easy to measure at the fuse itself.

If I was going to sell an expensive gadget that actually did something I'd be jumping at the chance to prove it's efficacy.