Aftermarket amp to stock head unit problem - BMW Forum

Hurdle · 04-22-2006, 08:38 AM

Ok so a while back I sis an aftermarket amp install in my car and used the instructions at http://forums.bimmerforums.com/forum...p/t-74181.html to use for the wiring part of it. Once everything was hooked up I noticed that if I had both rca jacks plugged into the amp then the sound coming from the sub was significantly less than if I only had one rca jack plugged in. I went back and check all the wires and they were all good so I don'tknow what's up. I can change which rca jack is plugged in and its the same thing. I've changed the line out converter (first was a Periperhal SVEN 4 and the current one Periperhal SVEN 2) and it's the same thing. Then I bought a new amp and still the same mess. Anybody else have this problem or know a remedy? Thanks...Chris

winters97E39 · 04-22-2006, 04:06 PM

are you using a speaker level input to RCA converter, or going from the preamp output from the head unit direct to the RCA?

I used wire taps and spliced an RCA cable into the preamp outputs from my headunit on my e39. sounds excellent.. positive wire goes to the center wire on the RCA, negative to the outside wire.

Hurdle · 04-22-2006, 04:16 PM

I went preamp to converter at the factory amp.

da_bull · 04-22-2006, 10:11 PM

Either the speaker wire input to the converter is backwards, the converter is wired internally backwards, or the subs are wired backwards from each other. What you are hearing (or lack of as the case may be) is the subs out of phase with each other. One is moving in while the other is moving out, cancelling each others air movement. Real quick, swap + and - on only one sub, see if that fixes it. It should and your done...

Hope that helps...

Hurdle · 04-22-2006, 11:01 PM

I only have one sub granted its dual coil, but the last sub I had was single voice coil and it did the same mess. I guess it may be switched around at the converter? Maybe the instuctions I used were wrong....

Wonderboy · 04-23-2006, 12:53 AM

honestly it sonuds like a possible bad ground. check all of the ground wires and make sure they are attached very well...

da_bull · 04-23-2006, 05:13 PM

Quote:

Originally Posted by Hurdle

I only have one sub granted its dual coil, but the last sub I had was single voice coil and it did the same mess. I guess it may be switched around at the converter? Maybe the instuctions I used were wrong....

what flavor of converter are you using? it may be your factory wires are backwards, but it does sound like they are out of phase somewhere. Ive even seen speakers wired backwards (DVCs especially), Ive had speakers out of the box that the magnets had no magnetic properties, a bunch of silly things over the years. Since you had a SVC and it did the same thing, it leads me to believe one side of the converter or its wiring is labeled backwards from where the wires go internally. swap the speaker leads at the input of the converter on one side only.

Hurdle · 04-23-2006, 06:13 PM

The converter is a Periperhal SVEN 2 which I've heard a lot of people recommend. I had a Periperhal SVEN 4 before that one and it did the same thing so I'm think it's not the converter but maybe the wires on the car. I went by the wire list that's on http://forums.bimmerforums.com/forum...p/t-74181.html I'll have to take a closer look at it when I get back home and try switching some of the wires around. Thanks for the suggestions!