Yeah wow is right! Thanks heaps Tung! I have no idea what the original tubes were (apart from the fact they were 6L6's), as I didn't really check before they died and were replaced with those Sovteks by the store.

If I can ask another question

How do I avoid buying 5881's labelled as 6L6's?

I wasn't planning on going NOS as I was going to save that cash for the tubes in the JTM45 I'm building. Aside from the suggestions you have already offered, I've heard JJ's sound good in this amp (all the way through). Any thoughts?

And thanks again for the read. I'm amazed you got all that from my pic which was designed to be more "arty" than "informative"