Re: best tubes for a 6505+?
I'd get Svetlana 6L6's, and buy 1 Tungsol pre tube for the 1st position. The stock pre's are fine for the others. No need to change them unless they're bad.
I like JJ EL-34's, but I've had some of their 6L6's that rattle from the internal bracing. The Svets are rock solid, sound great, and last really long.