Wiring question: LOC to amp?

[Sammy Sandbag]

Yes, yet another wiring question from me. Since I've blown my last amp and now have another, I need to know how everybody is wiring their LOC. It has been suggested that I go inline between the HU and OEM amp, that seems most logical to me as well. Question is; for a mono sub should I wire into the HU's sub output or a normal "full" output? And what wires are which? If someone has the pin numbers and/or colors that will be very helpful.

[smoketitan]

wire into the head unit front speakers/or rear speakers---pm me your email address, and ill send you the AV section in pdf, its 2.5mb though, or tell me which system you have base, mid grade, or rf, and I just post those pages

[eakes]

Originally Posted by sammy sandbag

Yes, yet another wiring question from me. Since I've blown my last amp and now have another, I need to know how everybody is wiring their LOC. It has been suggested that I go inline between the HU and OEM amp, that seems most logical to me as well. Question is; for a mono sub should I wire into the HU's sub output or a normal "full" output? And what wires are which? If someone has the pin numbers and/or colors that will be very helpful.

The HU has outputs for front and rear speakers (left and right for each set), there is no mono for the subwoofer. The underseat subwoofer is fed signals for both the left and right channels from the amp.

If you disconnect the black connector with the blue locking tab from the amp and hold it facing you with the lock tab up (as if you were going to plug the connector into your nose), there are two rows of sockets where connections are made to the amp - the top row and the bottom row. The top row counts from the left beginning at 5 and proceeding with 6, 7 and 8 (left to right). The bottom row starts at 21 then 22, 23 and 24. These eight pins are the input to the amp from the HU. The top row is (-) and the bottom is (+). Pins 5 and 21 are front- right, pins 6 and 22 are front-left, pins 7 and 23 are rear-right and pins 8 and 24 are rear-left.

Pin 9 is the Amp-On control from the HU. The remaining pins are outputs from the amp to the speakers. Power to the amp and audio to the subwoofer are contained in the other (white) connector that plugs into the amp.

[Sammy Sandbag]

Thanks a lot guys. One question though, pin 9 the amp turn on, is it 12V? If so, this might make a better power on for my aftermaket amp, rather than the power wire in the back of the HU I have now. That way the aftermarket amp only turns on when the radio is on, rather than on whenever the vehicle is switched to ignition.

[eakes]

Originally Posted by sammy sandbag

Thanks a lot guys. One question though, pin 9 the amp turn on, is it 12V? If so, this might make a better power on for my aftermaket amp, rather than the power wire in the back of the HU I have now. That way the aftermarket amp only turns on when the radio is on, rather than on whenever the vehicle is switched to ignition.

The documentation does not indicate that it is 12v, but I would assume so. I would check with a voltmeter to be sure however before connecting to the new amp.

[Sammy Sandbag]

Something else I gotta buy now. Thanks for the info eakes, you've been real helpful. I'm just gathering info right now, this new box is proving to be harder than I originally thougt. I beleive I'm going to scratch the downfiring plan, as all I could manage would be a 1/4" space between the woofer and floor. Mounting in facing up will give my a little more room, due to the slant of the seat. The box will have to extend over to the hump to get my full volume required.

[eakes]

Originally Posted by sammy sandbag

Something else I gotta buy now. Thanks for the info eakes, you've been real helpful. I'm just gathering info right now, this new box is proving to be harder than I originally thougt. I beleive I'm going to scratch the downfiring plan, as all I could manage would be a 1/4" space between the woofer and floor. Mounting in facing up will give my a little more room, due to the slant of the seat. The box will have to extend over to the hump to get my full volume required.

Since you are still in the planning stage let me toss in a little food for thought. In my LE I replaced the HU because I already had an aftermarket Blaupunkt head and I had an XM Commander satellite receiver I wanted to use. The AUX input on the Fosgate required more drive voltage than most devices with aux out can deliver so playing through it was not feasable without a line driver.

I replaced the HU expecting to also replace the speakers. What I found was the stock speakers are not that bad if you will avoid high volume settings - they overload pretty quick. I will probably replace the speakers in the rear doors (KC) with 6x9s in the near future. I used crossover networks that I purchased from RadioShack years ago (and never used) to feed the front door speakers and the dash mounted tweeters. The center speaker is not being used.

I made all my connections on the connector that plugs into the amplifier. I found that .063 molex male pins fit the socket almost perfectly. I attached these pins to my wiring for the crossover networks and jumpers to connect the HU rear speaker INs to the OUTS for the rear speakers. No soldering under the dash required. I put tape around the body of each individual pin and once I had all pins in place I wrapped the connector and pin assembly with electrical tape and stuffed it back under the dash. When trade time comes, I remove the tape, pull the pins out and connect back to the Nissan amp. Once I replace my HU with the Fosgate original, it's all back as it came from the factory.

In your situation you wish to retain the HU, but if I were you I would not use the Nissan amp. Outside of the established shortcomings of the Fosgate HU, the amp is a real weak link. A good quality four channel amplifier at whatever rated output your pocketbook will allow (even one that will only deliver 30 or 40 watts RMS per channel) will be much better that the OEM amp. You could power the front door speakers and tweeters using 1/2 the new amp and crossover networks. The other section of the amp could be set as a single channel to drive your rear subwoofer.

You asked originally, where should the LOC be located? By all means it should be at the output of the HU, not on any of the amplified outputs. The amplified outputs would probably be too high and overdrive the LOC/amplifier plus any distortion created in the OEM amp would be amplified in the new amp. Too much drive or too much distortion (or a combination of both) could result in blowing the downstream amplifier.

[Sammy Sandbag]

Thanks again eakes. Right now I'm just putting in a new sub. If you read my other topic on "Custom Sub Box" you'd see that I already built one ported box for two old RF 8"s that I had laying around. Long story short, it didn't sound like I wanted it to and the old RF punch amp eventually crapped out (probably because I was using the amps high inputs from the left rear channel post oem amp. I'm in the middle of building a new sealed box for an Infinity 10." I replaced my burnt RF amp with an Infinity 280w rms amp, that will go under the driver seat. The box will go under the back right seat, as it had to be larger than the original box I made. I also bought an inline amplifier for the oem HU's aux input for my mp3 player. I'll get all that installed once I hook up the new LOC at the location you pointed out. Eventually I may look into replacing the factory amp with a 4 channel and a new set of speakers, but this is a work in progress.

[eakes]

I can certainly understand that it is a work in progress.
It just occurred to me that it may be more convenient to make your connections at the rear of the HU instead of the amp since you are retaining use of the amp.

There are two connectors side by side at the rear of the HU, these are the ones with audio and power. The smaller connector has connections for the rear speakers and the amp out control. Looking into the connector with the lock clip up the pins count clockwise as 12, 11, 13, 14, 15 and 16. Pin 12 is the amp on line. Pin 13 is left (-), 14 is left (+), 15 is right (-) and 16 is right (+).

Whatever you decide to do good luck with the project.

[Sammy Sandbag]

Well, I'll wire it where it is easiest to access, shouldn't matter, after all they're the same wires. Are those speaker wires you mentioned for the front or back speakers? Could be useful info for fade adjustments. Thanks again.

[peanutbutter]

Stereo Install

Let me know if you have any questions. I have a change on that. THe brown wire is not a ground. It is the dimmer light wire. It did not have any power when I tested it, however the lights were not on. You would be better off running your ground to the chassis for the LOC.

[smoketitan]

hey sammy--wired my loc up at the HU, and received no hiss or dead sound, clear as button--so try that. especially since all you are adding is a sub--just right to the rear speakers to keep with the stock fade/balance

I get back on wednesday when my sub arrives for a full install roundup