Hey people. I am not really new to bass. I just never had the time to look at amps and what not. I'm not sure how all of the pre-amp, amp, head, cabinet thing works. Like, what does the head do etc....... I was just wondering if someone could fill me in with this. All have is a small Crate practice amp(in which you just flip it on and play). Now I am ready to move on to a bigger thing. I figured I had better know before I start looking for stuff. Thanks to anyone who fills me in.