The secret to a great amplifier...

Right.  High-end boutique brands never rebadge cheap stuff from China.

(Just to be sure, before buying that next power cord, go a quick visual search of Amazon and AliExpress.  You might be surprised.)

So were these Orange fuses inserted in the power amplifier outputs to the loudspeaker or in the AC Mains line to the unit?  Either I missed it or that installation point was never made.

A very long time ago a friend of mine had a Pioneer car unit in a boat . The fuse that was called for always blew when volume was increased so when it blew one time all I had was a much larger fuse and we used that and all of a sudden the sound was greatly improved. I don't know if some of these Hot Rod fuses are better but in that case being able to pass more current did in fact improve the sound greatly so it sure wouldn't hurt to experiment

The fuse that was called for always blew when volume was increased

You never heard it at the level you wanted.
Music always sound better when you want to hear it at the volume level you want, sound quality had nothing to do with the fuse, you were just enjoying it more, because it was finally louder.

Cheers George

Yes they improve the system.  Keep in mind fuses are also used inline for speaker/amp connects (no power only).  For those who are more budget minded the litlefuse 285 slow blow and 218 fast-blow are great options under $10 each.