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Amp Wiring (Battery to Boot)

PostPosted: Mon Oct 24, 2011 7:12 pm
by dylinquent
Going to attempt wiring up my amp in the coming week and was just curious if anyone's done this before on the MY07 wagons? My main concern is wiring up the power lead, is there any easy way to hook up the lead through existing openings running down the left side? Just not sure how to get it from the engine bay to inside of the passenger side. Also, the dude at Autobarn suggested just taking a signal off one of the speakers as I was intending on keeping the stock head unit. Has anyone does this before?

Re: Amp Wiring (Battery to Boot)

PostPosted: Mon Oct 24, 2011 7:19 pm
by mihai
dylinquent wrote:Going to attempt wiring up my amp in the coming week and was just curious if anyone's done this before on the MY07 wagons? My main concern is wiring up the power lead, is there any easy way to hook up the lead through existing openings running down the left side? Just not sure how to get it from the engine bay to inside of the passenger side. Also, the dude at Autobarn suggested just taking a signal off one of the speakers as I was intending on keeping the stock head unit. Has anyone does this before?


Where abouts are you located mate?

I've done my Liberty a few times now (upgraded from crappy 4 gauge to good quality 4 gauge and then to 0 gauge.) plus my mates Liberty.

The easiest way to get the cable into the cabin is through the grommit in the firewall, this comes out behind the glove box. Once there, you run is down the left hand side of the car. All the trim just pops off quite easily.

Re: Amp Wiring (Battery to Boot)

PostPosted: Mon Oct 24, 2011 7:29 pm
by teK--
Through same grommet that ECU harness goes through.

Re: Amp Wiring (Battery to Boot)

PostPosted: Mon Oct 24, 2011 7:31 pm
by dylinquent
From Adelaide I'm afraid, so it might be a bit of a treck for a lending hand haha. But that should be enough to get me started...

I think I should be able to use te back left speaker for a signal but was warned of running signal on the same side as the power. Was hoping if it was only for 1 metre it should be alright.

Was thinking of mounting the amp on the inside of the back left wheel well. D'you think I'd need additional earthing?

Re: Amp Wiring (Battery to Boot)

PostPosted: Mon Oct 24, 2011 8:04 pm
by garbo41610
What is the amp going to be running?

Was thinking of mounting the amp on the inside of the back left wheel well.

Inside the back left wheel well??

D'you think I'd need additional earthing?

Yes. Sand back some paint to bare metal with a decent lug, don't just use bolts here and there. Google "the big three" and do some reading to find out why.

was warned of running signal on the same side as the power. Was hoping if it was only for 1 metre it should be alright.

You shouldn't run power and signal cables in parrallel with each other, they should only ever cross at 90degree angles so as to minise noise.

Re: Amp Wiring (Battery to Boot)

PostPosted: Mon Oct 24, 2011 8:16 pm
by mihai
dylinquent wrote:I think I should be able to use te back left speaker for a signal but was warned of running signal on the same side as the power. Was hoping if it was only for 1 metre it should be alright.


Im assuming that the amp will be for a subwoofer?

If that is the case, why not take the input directly from the subwoofer already in the boot?

Also, if you are installing a new subwoofer, don't forget to disconnect the current subwoofer.

Re: Amp Wiring (Battery to Boot)

PostPosted: Mon Oct 24, 2011 8:22 pm
by garbo41610
But then it won't be fully tabouleh!

Re: Amp Wiring (Battery to Boot)

PostPosted: Tue Oct 25, 2011 10:35 am
by dylinquent
garbo41610 wrote:What is the amp going to be running?

Was thinking of mounting the amp on the inside of the back left wheel well.

Inside the back left wheel well??

D'you think I'd need additional earthing?

Yes. Sand back some paint to bare metal with a decent lug, don't just use bolts here and there. Google "the big three" and do some reading to find out why.

was warned of running signal on the same side as the power. Was hoping if it was only for 1 metre it should be alright.

You shouldn't run power and signal cables in parrallel with each other, they should only ever cross at 90degree angles so as to minise noise.


2 x Pioneer 600w/300wrms 12" subs. Sorry, that didn't sound right, I mean the inside part of the boot that would be on the other side of the wheel well. Thanks for the advice, I'll look up the big three. Yes, I could just use the existing sub's signal...

Re: Amp Wiring (Battery to Boot)

PostPosted: Wed Oct 26, 2011 6:46 pm
by solongaudi
You really should take the signal from the rear right AND left speakers using a summing circuit, otherwise there may be parts of the song your sub will miss due to the fact they are being sent to the right channel and not the left. See here for how to build said circuit, should cost you 50c in parts from Jaycar.

http://www.termpro.com/asp/pubs.asp?ID=115

#note, replace 'center speaker' in this article with 'subwoofer' and keep in mind the input impedance of your amp is probably up around 250kohm when doing your calculations, and also that your amp has gain and crossover control, so it should be unnecessary to use that.

Of course you could just use one of these from jaycar and wire it in parellel with your rear speakers and then just RCA to your amp from there...
http://www.jaycar.com.au/productView.as ... rm=KEYWORD

The choice is yours :-D

P.S. good call for asking first, I hate autobarn installers with a passion cause most of em are useless, there are guys on this forum who have made the mistakes and are more than happy to let others learn from their mistakes, giving you the best bang for your buck.