"Hmmm, did I put my old SU-V4X in the loft, or chuck it in a skip? "


Does not matter, it will be the latter.

On speakers that were right for them, they sounded good. But on most there really was no difference.

The main thing you get by biasing a transistor amp harder is damping factor at really low power levels. I got a PL400/2, damping factor 1,000. You can hear the difference, but not much. And the amazing part is they run the outputs in class B, you get the sound from the drivers mostly below a watt or two. Probably going to sell that thing, got a ton of blown speakers in the garage. Well not really. Haven't taken them out there yet to go with the other ones.