Hey gang, I'm a guitar player who's trying to learn/get better at playing bass. I have a Tokai P-Bass (really sweet, just back from a very long term loaner), a beater Yamaha BB300 (w/a Hipshot..there's a story behind that), and a Music Man BOO bass Stingray (yeah, I have GAS..or is it BAS(s)?)

. If I wanted an amp to practice with, and maybe use for small club gigs (assuming it would be DI'd thru the PA), what should I get? I know this might be a can of worms but... Opinions on Mark bass? Carvin? I'm in my 50's, so no SVTs please!! My back can't handle it!!
Oh, I also have a Sadowsky outboard preamp to help with EQ, if that makes a difference.
Thanks!!