@gavin1977 well yeah if you send garbage into the amp nothing will stop it from passing it on to the speakers. If the amp is transparent enough that is.
Power cables make a difference for sure. Driving factors are gauge, quality of conductor material, different dielectric, different lengths, connector material and plating, shielding…all make a difference to various degree and that depends on how good the power supply design is in the component. Power cables will also act as filters to reject noise going into the power supply and into the ac line.
The fuse on the other hand is a 1” long safety device with a hair thin piece of wire that melts when the amperage criteria is exceeded. Unless the caps are made out of 24k gold connected with unicorn pubes, the difference in sound quality this device can make is negligible at best and will never offset the shortcomings in a signal chain. I tried fuses long time ago and learned my lesson.
When it comes to power cords and signal cables I use the best I can afford.
Good luck!