some1

hey, my bass was really messed up in the last few months...here's the short story:

1. Power wire was bad so I ran a new power wire
2. I thought the amp was toast but a new one never solved the problem
3. I thought the sub was blown but a new one never solved that problem either.

So I'm wondering if its the preamps from my Panasonic deck? I have an aftermarket deck with Sub-woofer preamp out. When I tried any of 2 amps and any of 2 sub/boxes, the sub sounded like it was farting. I thought it was distortion but I don't know how/what to test now.

My question is basically how would I know if the preamps were blown in my deck? Would there be any sound coming out at all? If not, then its not the preamps. Any other ideas what may be the problem?

Thanks