Its been years since my workhorse V4BH has been serviced. I plan on taking her in and getting her re-tubed and re-capped this month. Now this is where I need assistance. I'm looking at the market for new tubes and realize that I have no idea what is considered good in the current production tube market anymore. I currently have some tired old JJ/Tesla 6L6's in there. I'm not unhappy with them, but I wouldn't mind tightening up the bottom end a little bit. If they are still considered good and reliable I would have no qualms buying another quad though. I've read good things about these new "TAD" (Tube Amp Doctor) 6L6's, any of you have any experience with these? Any other companies I should be looking at? Thanks in advance everyone!