I'm thinking of replacing the tubes in my SF Twin, and I want to know what the other people here recommend. I currently have ARS 6L6WGB/5881's which, according to everything I have read, aren't really a good choice for an amp made for 6L6GC's. Something about lower plate voltage. The amp breaks up earlier with these, and I've heard the life expectancy is rather short in a 6l6GC amp.
Also, is it normal for the glass near the base to be discolored silver like this?