I have a jensen 525 watt 12' sub and an alpine HU. can i just hook up the sub from the pre-outs on the back of the head unit without and amp? im just wondering becuz i have all stock speakers and i need a little bass even if its not very powerful. any help is appreciated!

 

in theory you could/can. All an amp does is juice up the signal but prempt outputs are designed to be combined with an amp, but since its rca cables, that proposes a problem. Anyone and everyone will tell you not to ever splice a RCA cable and use it but all a rca cable is (if u ever splice the wires apart) is a red wire and the copper wire, one posing as a ground, the other the power feed. So one rca jack acts as two speakers wires, the ground n feed all in the same.

My suggestion? Get on ebay and buy a cheap amp, just a cheap amp, $40 bucks even i've seen a decent amp go for on ebay. Don't risk the damage and with an amp, you'll get much better bass with any amp cause the rca just from the outputs probably won't even give you much of anything but i've never done that. Was told never to do that.

maybe someone else will tell.prove me wrong. =]

 

it is possible to do but you wouldn't even know it's on. the pre-amps only put out like 5 volts no power to run a sub. you will need an amp.

 

It's like this. An amp is made to produce power (amplify) for the sub. It's night and day between a amp and no amp... It's like running down the track with the throttle body open 1/4 of an inch then next pass you do it at full throttle.

You need an amp to power the sub. The HU alone isn't gonna do jack for you.

 

Even if you wired the sub off the deck amplifier the full range speakers would drown it out. You need atlest 150w for a 12.

 

I know this is not the direction you are tring to go but: Might wanna look into getting new 6x9's. The difference between decade+ old factory speakers and set of new polk or alpine's is night and day!

 

yes bottom line like everyone said you defintly need an amp. dont waste your time hooking it up without it will NOT work!
Sometimes you can find used amps cheap just make sure they work before you buy!