If I had to choose, warm bass and mids with a lot of life and energy to the delivery would most likely be the main goal I'd want out of the tubes. But again, I'm new to this so it is very well possible I don't know what I want until I find it, I understand this may be trial and error.
You could try Reflectors 6n23p. Very good description how to choose its a little bit above in this thread by rb2013. You can find its cheap. It's my favorite tubes for rock now.
But be carefull when choose its.
Russian tubes logos can be found here http://www.ominous-valve.com/russtube.html.
Year of production always printed on tybe (year in yy format).
Edited by Chs177 - 2/21/14 at 12:43pm