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.