Replacing the 440's in my Fifty/Fifty

[illswando86]

I'm just starting to learn the in's and out's of tube power, so I apologize but most of it is over my head. I've been given conflicting advise about replacing the 6L6's in my Fifty/Fifty. I'm interested in a set of TAD 6L6-GC STR's. I've heard that replacing the Mesa tubes with any other brand will require a adjustable bias mod from a few people, and others say that the TAD set is just the same tube relabeled by TAD and won't require a mod. Those same people saying they're the same tube relabeled then go on to talk about the different tones they get, so I'm confused. I'm looking for ballsy lows, sparkling highs, and creamy mids. I use clean and dirty tones about equally.
SO.... Questions
1) Is the TAD set any different than my STR 440's?
2) Would anyone here recommend them? (Or perhaps another reasonably priced quad of 6L6's that have won you over)
3) Will I need to have a variable bias added to my amp?
4) Is it worth it?

 

[MrMarkIII]

Many amps let you put in any set of tubes, then you adjust the amp to those particular tubes.
Mesa does it the other way around.
The amps are set one way, and then you need to buy tubes to fit the amp.
All you need to do is inform the tube seller exactly which Mesa amp you have, and the seller will be able to sell you tubes which match the amp.
I don't know who manufactures the TAD 6L6. They could very well be the same folks who make the Mesa 6L6.