Just bought this awesome guitar head and started doing more research on it and trying to learn more about tube heads since Ive been only using solid state. I took all the tubes out all Sovtecks power and pre amp and realized they are the original tubes since 89. I'm replacing them with JJ's and found that you don't need to bias this head because its a "plug and play" Dose anyone recommend getting it biased or should I just hook up the new tubes and assume everything will work ok? Or since its so old should I get it biased just to be safe? Also anyone recommend any good settings for this amp? I like it crunchy but also like being able to hear the notes I play. I use a Ibanez tube screamer with this and it rules.