Learn from the references I furnish you, & quit from talking emply.
Post your SS amp schematic you refer to all the time & let me show you how to add the stopper diode WITHOUT affecting the sound,
Until I read your schematic, i don't want to comment on your fuse & diode argument.
I repeat, as long as there is a bypass cap hooked up right at the powerstage, of adequate capacitance, e.g. 5600uF per the original post, the signal return path is completed locally there. This is exactly why the bypass cap is there for.
Or you have other idea what is the function of the bypass cap there?
Where is your answer to my question to you?
c-J