I am just learning how to play the bass guitar, and I want to purchase amp to practice with and that I can grow into. I am using a Fender Jazz bass and I want to play all types of music from Hip-Hop, Jazz, Rock, and R&B. I have few questions. 1. What is sound difference between an all in one setup that has the Amp build in and with the amp separate? 2. What our the advantages and disadvantages? 3. What our the sound differences between single speaker like a single 8" 10" 12" and 15" speaker compare to a duel or four speaker setup? 4. And last base on what I am trying to do, what type amp or combination should I purchase?