Ok, so I've got some old Presonus Blue Tube mic pre's that have been collecting dust. Let me first say this, I personally don't think the Blue Tubes are as "terriable" of mic pre's as everyone makes them out to be. True, they are on the low end of the spectrum, but they do add gain and a level of warmth. That being said, I want to try and see if I can get the most out of these pre amps and I'm wondering if a lot of the lack luster performance with these is the actual tube? I've never changed tubes in an amp (guitar, pre, or otherwise) and I don't know how they're rated, or how to shop for a good tube. They're elusive, sort of like a guitar pick-up. You don't know how they're going to sound unless you spend the cash to change them out... and THEN decide you don't like them. Anyway, so my questions are: A) Do you think there would be an improvement with new tubes. B) How do you shop for replacement tubes? (ie, power ratings, etc.) Any help would be appreciated.