Eclipse HU + JBL Factory Amp?

[trike]

Hey y'all, I've been lurking here for a few weeks now. Lots of great information and this forum has turned me on to a lot of great sites for car audio. Good helpful folks here, and I appreciate that.

2005 Matrix w/ JBL 7-Speaker system

I have an Eclipse 5425 to install with the Sirius radio tuner, and I'm hoping to integrate with the factory amp and speakers until I can upgrade properly later on. First of all, I checked and wasn't able to find an alternate wiring harness to bypass the factory amp, but I believe some Matrixes might have one.
I have a Peripheral Super Vendetta 4 (SVEN4) programmable interface, but I am having a problem with the wiring. Peripheral doesn't make a ready-made harness for the new JBL system yet.

My problem is the factory head unit has 4 "speaker wires" (Red:R+, White:R-, Black:L+, Green:L-) for amplifier input with a Black shielded ground.
How to deal with this? Do I need to convert to common ground or do I face larger problems?
Is it worth it?

Thanks much

[cam2Xrunner]

This kind of confuses me.

My problem is the factory head unit has 4 "speaker wires" (Red:R+, White:R-, Black:L+, Green:L-) for amplifier input with a Black shielded ground.

Personally what I would do if you don't have a prewired harness to bypass the amp, is to just hardwire the Eclipse. Find out what the neccesary wires are to power on and turn on the headunit, then run speaker wire from the headunit to the speaker wiring that comes out of the amp. Doing this you will basically be bypassing the amp, but the hard way

But if you want to make life alot easier-Just wait til you have aftermarket external amplifiers so you can hook them up using RCA's. Or just use the headunit's power and replace the speakers at the same time, and just run new speaker wire from the headunit to the speakers.

Although, I can understand your wanting to get the headunit in right away

[Iceman91]

I am having the same problem I stopped in at the best buy install shop today and the guy was on the phone with people from JBL and Toyota they don't do that seperate Harness anymore so he said to just wire your power and memory into the ignition or fuse for the radio and then run wires for the speakers that are coming out of the amp. IT IS A BEOTCH.

[trike]

Son of a DONKEY. This sucks more than I thought.
I want to build a modest SQ setup in the next 12 months or so, but I wanted to have the satellite for road trips and stuff for the time being. I also hoped the Eclipse might provide a cleaner signal to the factory amp and clean up the sound some.

To add salt to the wound I can't even bypass the amp with factory wiring!!!
Back to square one.

[trike]

There is a blurry version of the wiring diagram in this post:
http://matrixowners.com/forums/index...0&#entry648720

The channel inputs are on the top right of the diagram: (Red:R+, White:R-, Black:L+, Green:L-). There is a dotted line (shielded wire) which comes out of the head unit and goes around the speaker wires twice, once before the harness connector and once after on its way to the amplifier, but the wire doesn't actually reach the amp.

If the labeling on the wires in the diagram means that only a right and left channel are used for amplifier input, would it be an unsafe gamble to try and wire in 2 channels (pos and neg) of the SVEN4? Whats the function (dysfunction) of the shielded wire?

[Luc]

All of the OEM amplified headunits use the common ground for all the signal preamp levels. You could technically convert them to 4 RCA plugs. However, you do run the risk of inducing noise. I've measured the voltage output of these preamp signals, and it maxed out at 1.5V (!!!), so it's definitely low voltage. I've used the Vendetta4 with a Nissan/Bose system, but each signal had its own ground/return line, so noise wasn't an issue.

Shielding is always good for noise rejection, as that's the purpose. Likewise for twisted pairs. It's not a dysfunction, but a protection from parasitics coming out of car's electrical system.

I do NOT recommend using the OEM JBL amp, because it's really not that good. I've opened one up before (though from a Gen4.5 Camry), and they don't use FETs for amplification, but ICs instead. The JBL-logoed speakers are just as bad.