Fuses


I’ve read of views on whether amp fuses impart any sound quality or coloring. I had a recent experience that has made me re-think my views (fuses do not affect sound) and wondered if others had a similar experience. 
I have a Line Magnetic integrated amp. After heavy regular use for over 5 years, one day it just wouldn’t power up. After checking the power supply, I assumed it must be a blown fuse. I recalled that Line Magnetic sent with the amp two replacement fuses of the same type/quality that was pre-installed. I dug out one of them from storage, replaced the fuse and the amp powered up normally. 

What surprised and delighted me was the change in sound with the replacement fuse. Fuller bass, more detail and more warmth. I have rolled the tubes several times in the amp, and am attuned to the subtle changes that can make. Popping in a fresh fuse seems to have had a similar affect. And these appear to be cheap fuses, available for a few dollars at most. I don’t think I understand any of this. 
bmcbrad
Mijostyn is correct to the extent that no tests of these things, to my knowledge, are ever undertaken.  However, some people have fun, experience pleasure employing  expensive, unproven tweaks.  To each his own.  An anology:  despite an apparent lack of rigorous listening tests, we all know that there is a meaningful difference in SQ between tube and solid state amplification.  (I know the differences in harmonic distortion can be measured.)
When you plug it in and try it out, that is a test. When the tweak works, it is proven. All the more so when it has been proven to work over and over again with hundreds and thousands of people across a wide range of systems. Fuses are tested and proven to work.    

An analogy: despite an apparent lack of experience some people nevertheless opine. That doesn't mean their opinions are tested or proven true.
Just based on a preponderance of the testimonials the fuses may be exerting some effect. But, Millercarbon, your “test” as you describe it, is biased, and its reliability does not rise above the testimonial. For example, the FDA would never approve a drug based in a bunch of testimonials. Finally, if a consumer pays several hundred dollars for a tweak, and it has no effect, then consumer would either have to seek a refund or tolerate a noxious cognitive dissonance. The brain may take a third path,  the path of least resistance, that is, to believe in the tweek.
My posts concern testing & evaluation, not the efficacy of fuses or other tweaks.
Which circle of Dante's Hell is this? 
How many times does one beat a dead horse?
Why is it all the newcomers think they have the reasoned answers that have been shot to hell long ago?

All the best,
Nonoise