I will try to keep this as short as possible, but there will probably be lots of questions and info. Thanks in advance for your help. I haven't been playing bass for too long and I am kinda green when it comes to gear. I am currently playing with and SWR wkmn's 1x15 with a 2x10 Carvin extension cab(when needed). I currently play a G&L ASAT(electric) & 60's Kay Upright in the style of Country/Blues. The SWR has worked great so far (not real great for Upright), but at my last gig I had the volume up half way, and I know that I probably need a more powerful rig. I would like to lean towards getting a 4x10 cab because they just sound better with Upright, but I need help with the amp head. I do not understand the whole Power amp Preamp thing, so any explanations would be great. I am leaning towards an amp with at least 400watts @ 4 ohms, but there are so many to choose from. Would I be better off doing the Rack thing with a Preamp, Poweramp, tuner, etc... ? I have money burning a hole in my pocket, but I do not want buyers remorse. I think I have decided on a 4x10 and a 1x15 made by Avatar, but I would like to settle on the "brain" issue before getting them. Thanks for your help and sorry it is soooo long.