The guru on fuses:


For two years, I have asked why and how fuses could possibly matter. All I got was arguments of faith, pro or con. I needed a real audio guru who actually knows. Here is a link from John Curl’s discussion on Parasound’s website. He engineered and designed some some great equipment, including some Mark Levinson gear, The Grateful Dead’s 30 plus McIntosh amp powered Wall of Sound, and his admittedly, somewhat price compromised Parasound designs. He discusses the electrical properties of standard fuses, showing how they are compromised. The entire article is quite enlightening, but to skip to the fuse section, go to the bottom half of page 6. https://www.parasound.com/pdfs/JCinterview.pdf

128x128danvignau
So, you of course have measurements confirming your hypothesis, not to mention calculations putting some bounds on the effects?  You are pretty much stating the obvious, like cables have resistance, but without quantifying it does not mean much.
bluemoondriver

Fuses are tiny pieces of low value resistors which when heated to the correct temperature by excess current passing thru them, melt and avoid damage & a possible fire.

They contribute ABSOLUTELY NOTHING to the sound.

I just measured the resistance of 2 ’normal’ fuses:

a 500 mA fuse had a resistance of 0.7 ohms. Meaning, that the power dissipation on it will be I^2 x R = 0.5 x 0.5 x 0.7 = 0.175 watts as it is about to blow. It means that the fuse will melt at such a very low power dissipation, when its limit current is reached. And the voltage drop across it at that current will be 0.5 x 0.7 = 0.35 volts. Absolutely negligible. This fuse is obviously for a very low current circuit.

A second fuse I measured was for 8 Amps, more typical of a 2 x 200/250 watt 120 VAC typical amplifier. Its resistance was 0.3 ohms. This means it would dissipate about 8 x 8 x 0.3 = 19 watts. And the voltage drop across it at that current would be 2.5 volts just as it is blowing. Again totally negligible voltage drop.

What makes them different is the melting point of the material used in them. Note that the one that passes 8 amps must withstand a dissipation of about 20 watts before it blows whereas the 500mA fuse is required to blow at only 0.175 watts.

Note that I did not mention temperature. When a fuse is working at less than its maximum limit, it is obviously still dissipating power and is likely to get warmer/hotter. This typically will increase their resistance, meaning the power dissipation on them is likely to increase FASTER than I^2xR with increasing current, meaning they start actually dissipating more heat as they get closer to their blowing current.

Here is a link which explains that relationship, towards the bottom of the page, which headlines "PTC characteristics", if you really want to understand them deeper:

https://www.littelfuse.com/~/media/electronics/application_guides/littelfuse_fuseology_application_g...

Basically, fuses HARDLY affect the currents passing thru them. They are almost ’transparent’ as they should be, not to affect any operating parameters in the rest of the circuit.

Fuse believers are just hearing things which are not there. They need urgent help.




blah blah blah blah, etc.  Only direct experience will give you any TRUTH.  Create Audio Fuses cost $20 from Parts Connexion.  You try, you like, you don't like, you hear a difference, you don't hear a difference.....but at least you listened.......instead....you guys just blah blah blah blah, till you die.  Not much truth or happiness in that game.  Have some fun.....open your mind.....try something new.......the ego does not like new.....it likes the same thing over and over again.....define and defend.....that is what the ego does.  Whereas an open human tries new things and knows that "not knowing" is really fun......and sharing new things that you try is even more fun.  So, what are you sharing?.....your ego?.....or your soul?  The choice is yours....every second.   Thank you for listening to my sermon.....please come back next Sunday for another edition......however, it will say the same thing.....the only thing to say......which is, we are infinite, we are beautiful, we are love, we are joy.....and that is forever and ever......bless us all.
Kakyol - thanks!

So, the physics of the fuse is negligible.

Negligible compared to running 240v vs 120v ?
Well I have listened, and have "made" many audiophile friends listen to, on their system, with their boutique fuses, and my generic new ones. Not once, literally not once could they pick out the boutique fuse blind in a power supply circuit. That is 10 people, about 15 tests. How many times do I have to replicate the test to prove the point?

The reality is, though, that I could detect a fuse change with equipment, measuring only at the power supply, at the very limit of continuous power, but would be very difficult, if not impossible to detect at the output, due to the supply filtering, and feedback, either local or overall of the amplifier.