Anyone tube rolling a KT88 amp should check out the new Canada Fuller tubes. They sound a little bright right out of the box and need a full 100+ hours of break-in but then smooth out and are better than any other I have heard. Lots of slam, strong tight base, a clean relaxed midrange, and smooth extended highs. I recently went from Audio Note Conquest Silver 300B amps to Quicksilver V4s with these tubes and the Canada Fullers remind me of a 300B on steroids.