sub pre-amp outputs

[steventadams]

So if i want to bridge my 4 channel amp to 2 channels and then use each channel to power a sub which are in the same box, do i need two sets of sub pre-amp outputs?

 

[karl_burns]

Check your amp. It might have one full range set of inputs, with an on-board cross-over so that you can get rid of all the high end frequency so only the low-end goes to your subs.
Typically, if the head unit doesn't have a "sub" output, then it's a funn range output and you'll need to filter the signal (with the amp).
What's the amp?
Karl

 

[steventadams]

its a jensen powerplus840. i got it for really cheap and had planned to use it to power my 4 door speakers. now im not but i want to keep that option open later by bridging it to power some cheap subs... and if it matters i have a Valor 702W head unit and it only has one sub pre-amp output.

 

[sjr033]

With out knowing what amp you have. Alot of amps let you run 4 channels with only 2 inputs. Expecially when you bridge them. Even if you can't they make an rca cable "Y" that you can get at Radio Shack or ebay.

 

[sjr033]

It looks like your amp has a 4/2 channel switch on it. So if you switch it to 2 channel, you should be able to just use the 2 channels. Did you get a manual when you bought it. Usually is gives a diagram for wiring.

 

[karl_burns]

From the looks of it, there will be a full range input on the left (RCAs) and you'll then look on the right, and put the crossover at the lower setting (it might crossover at like 80 or 100 Hz). Anyway, look at the installation manual for a two channel setup. Most likely, you will run the speaker wires to the subs from the outer sets of speaker connects. Amps are typically set-up in this manner. Consult the manual above all else. If you ahve any more specific questions, post. I couldn't find an electronic copy of the manual, but I'm sure it will be fairly straight-forward.
You should be fine. Remember, they sell amps to anyone with a pulse and money, so you can't blow anything up. I'm living proof.
Karl

 

[karl_burns]

http://store.electrogalaxy.com/jenpwrp840.html
^ link to the amp if anyone else wants it.
Karl

 

[steventadams]

ok so according to the manual i can run two subwoofers from the amp, but my head unit only has one sub pre-amp output. can i run just one RCA cable from HU to amp and then split that signal to two subs on the output side of the amp?

 

[sjr033]

When you say 1 rca you mean 1 pair, a right and a left. Then yes you should be able to. You will need 1 channel to supply signal to each bridged pair.