marxw13

Hi everyone- I recently purchased a 2015 TLX base model. no ELS audio. I'm looking to bypass the factory amp and add a 4 channel amplifier and subwoofer amplifier . I'm an installer so I already have all my wiring schematics and colors, as well as factory amp location. My method of doing the 4 channel involves tagging all the speaker wires where they come together in one location rather than running wire to each speaker individually. I'm going to cut the speaker wire at the factory amp and use one side as the input to my line out converter, and the other as the output from the new amp , and just extend the wires back to the amp in the trunk. my only uncertainty is this: do I need to grab the signal for the line out converter on the input or output side of the factory amp. Logic says input side but I have done a couple other cars such as older Lexus models where the volume is controlled by factory amp, therefore the signal must pass through it or you lose volume control . Has anyone done this? thanks

310cem

did you ever get this done?

marxw13

Yes. You have to grab the signal on the output side. If you disconnect the input side the whole radio goes dummy and loses all functionality. Im actually doing a full custom trunk. Ill post a thread of the build when im done.

01LSi

Please come back and explain the process. I have all the parts and I'm ready to install. Honestly I'm willing to shoot you a a little money I can offer at this point as a thank you ... I really want to install this while we have the sun. Can we get details prior to the install being finished, particularly which wires pre and post amp you tapped into and what you had to leave be?

My original plan was to tap into the pre amp wires, I would think that's still necessary right?

For the pre amp side I'm pretty confident I finally found a pre amp harness to match without having to splice/tap anything at least for the preamp.
See link. I purchased this, but if it's not worth it I can still cancel the order.

https://www.sonicelectronix.com/item...75989815428406

Still looking for a harness that will match the amp output.

know610

When doing this, do you guys add OEM Integration like for example JL OEM Integration interface, Car Audio - Processors - OEM Integration

Thanks

01LSi

I'm planning on tapping into only the pre factory amp speaker wires. In the base model of my 4cyl TLX there are only two pairs of speaker wires FR and FL. In my base model, the factory amp takes those two speaker inputs and creates the additional channels for RR RL & Subwoofer.

I bought a Fix82 and a Twk88 and the setup will be in this chain -

Stereo FR & FL speaker wires --> Fix82 --> Twk88 --> Aftermarket Amplifier

Fix 82 - I will tap into the pre factory amp FR and FL speaker wires that come from the stereo and connect them to the Fix82. There is a chance the Fix82 isn't necessary in my scenario, what it does is flatten and equalize the signal. There's a chance that it is already flat and equalized pre amplifier, but I have not checked, and haven't researched thoroughly how to check, nor have I heard input on if someone else has. Just figured I'd buy it and be done with that. Then the output side of the Fix 82 I will send by optical cable to the Twk 88

Twk 88 - will receive optical connection from the 82, this unit will expand my system to 8 channels/speakers. I'll send this to the aftermarket amplifier(s) either by optical cable or traditional RCA connections.

If the signal from the factory stereo is equalized, you can skip the Fix82 or Fix86. Fix82 requires 2 channels from the factory stereo in order to operate, Fix86 requires 4 channels from the factory stereo.

My understanding is that you should be able to use these JL processors after the factory amplifier, but I didn't want to do that.

01LSi

Here's JL's response on using two channels from a factory stereo system and the benefits of the Fix82/86 and Twk88.

"... the TwK 88 can accept up to 8 volts of input signal. As long as the output of your factory radio does not exceed this you could use some RCA adapters to tap into the factory signal and use them as your analog/RCA inputs into the TwK. You could then split the signal to up to 8 channels of output. You could play a Sine Wave test tone through your factory radio and test the A/C output voltage at the factory speaker wires at 3/4 volume to see if it exceeds 8 volts. Here is a link to the tone.

https://www.dropbox.com/s/1cql6fv1hpaw4u3/Sine%20Wave%20-%201%20kHz%20-%200dB.wma?dl=0

If it does exceed 8 volts you could limit the factory volume to a point that is before the 8 volts point to avoid clipping the inputs of the TwK. You would then need to use the DRC-200 as your new master volume.

The FiX 86 would need at least 4 channels of input to fully calibrate. It would need at least full range front channel information on inputs 1 and 2 along with full range input on inputs 5 & 6. The FiX 82 would only need 2 channels of full range input to calibrate and would provide you with 2 channels of optical output or analog output. The main advatages of using the FiX 82 are that it will use its processing power to do all the frequency correction for you automatically. This will provide you with flat frequency response without having to use the TwK 88's processing to do so. This leaves more processing power available on the TwK 88. The other benefit is that it also provides the low level analog output or optical output which is better for feeding other devices such as the TwK.
I hope this helps. - Eric"

01LSi

marxw13 you said the whole stereo system goes dummy / haywire if you disconnect the pre amp harness

do you know if it goes dummy by leaving the harness plugged into the factory amp as is and only completely cutting off the two pre amp signals FR and FL

also did we verify whether cutting off only FR and FL entirely from the amp will have us lose volume control on the factory stereo

Thanks again for your replies.

marxw13

no unfortunately I didn't think to check any of that because I never anticipated the hissing problem beforehand. I just went straight for the signal after the amp. I'm almost dont with my project now so its a little late for me to bother checking

01LSi

Cool I'll check on mine and report back!