I tried some cryoed Radiotechniques from ASTI (mid 1960's) vintage. In my system they had great bass and transparency, but the upper midrange was hard and ultimately too fatiquing. They might work better in a system that is a little dull at the top end. I then tried 1950's Longplate Mullards from Brent Jesse Audio. WOW - these have the magic. Very smooth and silky. Very musical. I love them. I occassionally miss the great bass from the Radiotechniques, but the Mullards are just so involving - I listen for hours. I have not heard any other tubes, I love the Mullards and have stopped my tube rolling here. The 1950s Mullards are expensive, but some of the early 1960s vintage are supposed to be nearly as good. The readily available ones from the 1980s are supposedly not as good. Many people also like the telefunken smooth plates and the amperex 7316, if you can find them. But I would start with some Mullards. They made a very noticable difference in my system (Vandersteens and Music Hall CD 25).
