Do tube pre-amps need bias adjustments?


I'm new to tubes. I'm thinking only tube power amps need bias adjustments, not pre-amps, but I'm not sure.
reedthis
Ssglx,

Yup, got it yesterday. Sounds terrific!
Thanks, everyone, for the confirmations.
I was surprised to discover that my BAT VK-31 preamp does have bias adjustments. When I sent it back to the company to be upgraded, I was told that the technician biased it for the NOS tubes I had installed in it.
Well, I guess I don't know anymore than I did when I first asked the question, then. Oh well.