Maybe with something made at the turn of last century would moving a fuse around inside its holder make a difference. It would have to be poorly made, bordering on primitive. Never seen a fuse do what Georgie says with his summer vacation slide shows.
All that supposed corrosion would be evident throughout the chassis and not just at one tiny point of contact where the fuse resides. Listen to yourselves. You're delusional and grasping at straws.
Going one step further, how is it that a different fuse can't possibly contribute to the sound of an amp but just moving an existing fuse can, when all it's supposed to be is safety feature and not at all capable of affecting the sound? You can't have it both ways.
All the best,
Nonoise