Andi, the socket thing isn't a massive upgrade, but it makes a subtle improvement. The fuse I was referring to incidentally was the one in the mains plug attatched to your block.
If you want a really noticable improvement, take the neutral pin out of a spare plug,and replace the live pin in the plug on your block with this, then wire up the plug as normal. You have just bypassed the fuse, so that now all your gear will not be drawing off of a single 13A fuse, and you will no longer hearthe sonic degradation that occurs. Your gear will now have a new release of life!
Oh, and in case you ask, I don't believe plug fuses in hi-fi equipment are necessary. The rest of the world manages just fine without them