Originally Posted by
Astrofriend
Hi,
I'm going to replace the radio in my Crossfire. The original is the one with GPS and four (or is it 6 ch ?) channel power amplifier. The original is functional and sounds okay, but has some pixel defects in the display. There is no problem with my speakers so I keep them for the moment. The new radio is 4 channel, 4x65 Watt. The reason to replace it is for the USB connector and MP3 media file play.
I have searched here but I don't find the answer I looking for. Questions:
1.My idea is to replace both the head unit and the power amplifier. Even if the new radio is a cheap one it must be better than the 17 year old original power amplifier, or ?
2.I can't find what impedance the sub woofer speakers have, they are double coils, but is it 2x2 Ohm, 2x4 Ohm or something else ?
3.When I look at the drawing schematic it looks a bit strange, they have connected the radio speakers power outlet, not the lineout to the power amplifier, any reason for that ?
4. In the drawing both the body control module and the controller antilock brake are connected to the power amplifier on pin 3B, I guess that's a signal to let the speed of the car control the volume, correct or ?
5. There are no + or - sign in the drawing at the speakers, I need to know that to get the speakers in correct phase. Anyone who knows ?
I include the drawing I found which I use when planning how to connect the new radio.
The amp is four channels, the head is two channels - no idea why they did this, other than it's a small cabin so they didnt' see the need - but I disagree, my SE has a four channel JVC system in it and I'd never go back.
1. The OEM amp is not bad. Not telling you to not replace it, just that it's 'not bad'.
2. I believe they are dual coil, 4 ohm. (Given the age of the car and that you are replacing the amp, just go with single coil speakers that are compatible with the amp you are going to use.)
3. Noise. Using speaker lead outputs makes it a noise-resistant system (low Z, high voltage of the speaker leads beats high Z, low voltage of the line out), its an automotive environment after all - this is the one thing I agree with about their design. The mobile environment is NO PLACE for "line out" use, those who tell you different have not worked for JVCKenwood for years. I have.
(I work now for EFJohnson Technologies, a subsidiary of JVCK.)
4. There is an auto volume in the Roadsters, not sure about the coupes. Roadsters have: Wheel speed sensor input on A1, Backup lamp input on A2 (Non-Navigation) or Reverse indication input on A2 (Navigation).
Not sure on Coupes and no, I cant remember why they feed backup light indication to a head that has no rear camera.
5. You are using the wrong diagram. See my next post.