Easy. Kondo M-77 preamp and spend the change on a SUT to go with it.
I had the Kondo in my system for one all too brief evening and it was a game-changer - I learned that evening just what a truly exceptional preamp can bring to the table.
My EAR 912 is far from shabby indeed it's the best pre I've heard in my setup at least apart from the Kondo, beating a tubed Kondo M7. But if I had £50k burning a hole that's where I'd spend it.
http://www.6moons.com/audioreviews/kondo/hero_open2.jpg
http://www.astrasuite.com/client-sys...10201-0010.jpg
Edit: just to add I'm happy to answer the OP's question in the spirit in which the question was posed .... since no-one is **actually** going to give any of us fifty grand to play with, none of us need to get into any kind of virtue signalling/moral olympics about it - this is just a bit of fun.