Im beginning to understand this now.

Sorry about my previous lack of understanding.

This is how I believe it works...

1) Try piece of hifi. Discover that the difference, if there is one, between the new piece of kit and the old one is either hard to hear, or maybe not there at all.

2) Disregard the blatantly obvious solution of - ''Dont buy it then''

3) Instead, blindfold yourself, and get a chum to swap it backwards and forwards at least 16 times to see if this negligable difference is easier to hear when you cant see what you're doing.

Dont think Ive missed anything out?

Look! and I didnt even say it was sad.