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Discussion Starter #1
I just want to double check this.

So when I add an amp to the stock radio, all I have to do is run the cabling for power and just tap into the L/R fader wire in the rear deck and I'm basically done?
 

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What are you trying to do? Replace the amp and speakers or what?
 

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Discussion Starter #3
adding 1 sub, and using the L/R fader on the stock radio as the bass volume.
 

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Fader is front/rear. Balance is left/right.

To add a sub you can tap into the rear left and right signal wires before they go into the Bose amp and run them into the aftermarket amp using RCA plugs. It works well to sacrifice one or two RCA cables and either cut one in half or cut the ends off two.
 

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If you want to do a good job of adding an amp to your stock system, buy something called a PAC LC-2. The PAC LC-2 converts the high level audio signal (used by Bose amp) to a low level audio signal. You can use high level audio signals on some aftermarket amps, however the quality is never as good. The other advantage to the LC-2 is that there is a variable gain control on it so you can actually control the gain to the amp. The LC-2 is also quite simple to install.

The option that would give the highest quality while using the stock head unit would be to use either the MTX Re-Q bass converter or the JL bass converter. However, the Re-Q is about $150, and the JL is around $225...that being said, I would still go with the LC-2.
 

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^^ that isn't necessary if the line level signals are used before they go into the Bose amp.
 

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^^ that isn't necessary if the line level signals are used before they go into the Bose amp.
I know it is not necessary (if the amp has a high level input), but honestly the PAC LC-2 is about $50 (including s&h) off eBay. I would rather pay the extra little bit so that I can have a good quality low level audio signal with a variable gain control.

I have worked in the car audio business for a while and that LC-2 is such a slick way to do a factory integration. Maybe I should post a DIY to show people how to take the LC-2 apart so they can mount the gain control where they want in their car. I usually put it in the extra button plug located by the trunk switch and VDC button.
 

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The Bose amp is the evil part of the system because it adds the awful equalization so tapping into the post Bose amp signal and dropping it to line level with any device defeats one of the reasons to bypass the Bose amp. Another reason being the low power.

The signal going into the Bose amp is low level and is suitable to connect RCA plugs onto the wires before they get into the Bose amp and feed the signal directly into the line level RCA jacks on any amp.
 

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The signal going to the amp may be suitable, but it is not optimal. If I owned a g37 I would want the best components going into the install. When you use high quality components you will be able to hear the difference between using and not using a bass converter, such as the LC-2. In addition, if you use the fader to control the bass level you will mess up the tune of the stereo. I believe that an isolated gain control is far superior.

When you use a bass converter there is almost zero chance of the anything failing. The wires used in RCA cables are very thin. If you do not do a perfect job of stripping the insulation and soldering, the connection could eventually become stressed and break. I live in a climate with huge temperature swings (90*C swings between winter and summer). I have found that it is simply better to build a system to the highest quality to avoid problems.
 

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But how can the system be optimal and of the highest quality when the signal first goes through the Bose amp where the signal is altered and the bass level reduced as the volume increases?
 

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I can see how the LC2 can be used to add a sub to a stock system if someone intends to keep the Bose amp, but I wouldn't run the signal thru the Bose amp if I'm replacing it.
 

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I am sorry. I should have explained how the LC-2 works. You tap into the left and right front speaker signal before any amplification occurs. The LC-2 then generates its own bass output signal. RCA cables are then ran from the LC-2 to the amp. I like the LC-2 because it is generating its own bass signal off the front speakers (which are the most dynamic).
 

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Well with that explanation of not going thru the Bose amp first, I would agree with you. That would be a nice device to have.

What is your preferred method to tap into the front peaker signal, pre Bose amp?

I assume the signal then continues thru the Bose amp to the door speaker.
 

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I am interested in knowing this as well since I am just spliced off the 6x9 right now and am looking for ways to make my sub sound better.
 

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I used to have an epicenter in my cars. I've had the same unit since about 1990 and it has been in at least 4 cars.
 

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I like to tap into all my wires at the back of the car. I try to find all of the factory wiring in the trunk because that is probably where the aftermarket amp(s) will go. I do this because I like to have the shortest RCA cable as possible. The g37 factory amps are under the trunk mat on the left side of the trunk floor. After you have found the amp signal input wires, carefully strip back the insulation for the front speakers. Solder and tape the appropriate LC-2 cables onto the cars left/right speaker amp input cables. Then run the RCA cables to your aftermarket amp. There are also grounding cables on the LC-2. You can ground the LC-2 if you are getting any alternator whine. However when you have such a short RCA cable you probably won’t run into that problem.

Here is the part people don’t know about the LC-2. There is a small hex key at the bottom of the gain knob. If it is loosened, you can take the knob off. There will be a small nut revealed that you can take off. Remove the nut and DON’T LOSE IT. You can then pull the face plate of the LC-2 off and it will expose the circuit board and 6 wires connecting the board to the gain knob. You can extend the 6 wires to any length you want so the LC-2 control module stays in the trunk, but you can mount the gain knob wherever you want.
A good spot to mount the knob in a g37 is the extra bung in-between the heated seat switches. Drill a hole in the plastic bung the same size as the metal stem the knob connects to. Push the stem through the hole you drilled and put the nut back on (the nut that held the stem to the face plate: the one I told you not to lose). Push the bung back into its original position in the car and re-install the knob by tightening the hex key. For this install, you will have to take apart the center console to gain access to where the heated seat switches and extra switch plug/bung thing are. Once it is finished you will have a nice bass control knob in-between your heated seat switches which will give you a 0-8db control of the gain being sent to the amp.

A great place to put an amp in a g37 is under the trunk mat and plastic on the right side of the trunk. However, you really should install computer fans to ensure proper cooling of the amp.

“CashMonay” – One reason your sub may not sound good is because your sub is using an amplified signal that is already been through a low pass filter. The 6x9’s in g35’s are on a low pass filter so they can act as subwoofers. It is best to run a dynamic signal to aftermarket amps. That is why it is best to use the front speakers as a signal input for an aftermarket amp.
 

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I will look into this and get back to you for sure, I might just switch the connection over for now and if I find I need the lc-2 I'll invest in one
 

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Discussion Starter #19
Without doing any upgrades to the electrical system, extra battery/ stiffening caps/ new alternator, what is the most powerful amp that I can run without issues?
 

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A 500 watt amp should be fine. I had 1000 watt and 600 watt Alpine amps with just a cap.
 
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