Had to think twice before posting here as I may be perceived as a heretic. But I think just for the sake of people who stumble across this thread looking to learn something it has to be said that any amplifier which sounds different after you change the fuse has some pretty dodgy engineering.
Fuses are there for one reason - to protect you and your equipment from harm. A design engineer has put them there for a reason and if they've done 1/100th of a decent job they will have no impact on the sound whatsoever.
I would never design an amplifier without correctly rated fuses and I would never put them in the signal path... To qualify what I mean by the 'signal path' I mean the conductors that carry the signal - power supply rails are not part of the signal path (I have a feeling that some people here would claim my fridge is in the signal path because it's plugged into the same ring main).
Let's assume that the fuses we're talking about are between the transformer and the rectifier, that would mean that any small change they make have to survive the AC signal being chopped up by the rectifier, smoothed out by the reservoir capacitors and ignored by the ripple rejection designed into the amplifier... and that's before they even get near the signal path.
Running off batteries is a different matter, they deliver a clean DC supply with a low impedance and regardless of fuses may show an improvement to sound particularly with phono or headphone amps.
Fuses are there for one reason - to protect you and your equipment from harm. A design engineer has put them there for a reason and if they've done 1/100th of a decent job they will have no impact on the sound whatsoever.
I would never design an amplifier without correctly rated fuses and I would never put them in the signal path... To qualify what I mean by the 'signal path' I mean the conductors that carry the signal - power supply rails are not part of the signal path (I have a feeling that some people here would claim my fridge is in the signal path because it's plugged into the same ring main).
Let's assume that the fuses we're talking about are between the transformer and the rectifier, that would mean that any small change they make have to survive the AC signal being chopped up by the rectifier, smoothed out by the reservoir capacitors and ignored by the ripple rejection designed into the amplifier... and that's before they even get near the signal path.
Running off batteries is a different matter, they deliver a clean DC supply with a low impedance and regardless of fuses may show an improvement to sound particularly with phono or headphone amps.