KT66s - yes, they are excellent, if in AB1UL. They save on heating bills, too.
I retired mine in the early 1970s and switched to 2N3055s in the Quad 33/303 which I still use in the lounge.
I agree that the sound quality from the Ipod isn't up to that standard, and sounds pretty ropey. The Ipod sound is in the "£100 amplifier" range, at best.
What I did notice was the improvement in sound quality when I dumped the Sony CD player and got an upmarket Arcam. I now play CDs in preference to vinyl - the sound is as good in most cases, and the scratch and hiss is gone. I don't think I've played one of my LPs in some years.
The Quad FM tuner does an excellent job on Radio 3, although I had to put up a Yagi pointing at Wrotham last year. I know the BBC say they haven't turned down transmitter power, but the signal was getting noisy. I changed the valves in the tuner and checked the alignment, but it made no difference. The Yagi solved the problem completely.