I finally got the tubes installed and first impression is wow!!
So I installed a pair of 6P30B-R tubes to Lil'Devil and they sound really cool.
Haven't yet time to fiddle with the bias but first impression is good.
I just wired the two anodes together to achive all power from the tubes.
When I'm done with the output stage I have to try 6N17B-V preamp tubes that I also have....
So I have now a russian modded miniature trainwreck.
Here is a pic of the thing.
http://www.flickr.com/photos/30142014@N07/12853209525/
And here you can see the difference between 5902 & 6B30P-R
http://www.flickr.com/photos/30142014@N07/12853604694/