Headunit the problem?

[Bobby32]

I have the big 3 done, 100ah Sprinter underhood, 2 runs of power/2 runs of ground, and a 134ah c&d battery in the back. Batteries are still good and all connections/grounds are good. My amp is mint condition, nothing wrong with it. Now that thats out of the way, I think my old alpine 9884 is causing an issue. It only has 2v preouts and I think that is causing clipping/voltage drop. I pretty much have to turn the gain up pretty high- like 3/4 and the volume to 18-22 (out of 35 I think) for it to hit hard. Anything around 1/2 gain and the bass is super weak. It has always been like this with all my previous systems. Should I be getting a better 4-5v headunit? Im running about 2-3k watts. Bass boost is off on the amp, and bass settings on the HU are at 0.