My bass is active SR 505. What does the active part do to a bass sound and does it pertain to the way it uses its preamp? What does the preamp do? I would think it gives the sound a boost. I tried something that I thought was a pretty good idea but it turns out that it didn't work out like I planned. I have headphones and I figured that my bass is "active" I would be able plug in the phones and hear it just fine..... not the case. Can someone please explain this to me?