Don't know about VTL but most tube amps provide for individual biasing of tubes and you should set the bias for the new tube at the same setting as the other tubes in the set.
Biasing for new tube
I'm new to the tube world so I apologize if this is a no-brainer question for the experts. I am replacing one tube in a VTL MB 185 that arced on me. Do I need to check bias after the new tube is installed -- the VTL manual tells me to do so when I install all new tubes, but it's not clear as to the procedure when replacing a single tube. I'm getting the replacement tube from VTL. Any help will be greatly appreciated.