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Trying to determine what pin 1 (SWD +B) on amplifier connector B is on my 2011 TL SH-AWD. I am bypassing the factory amp and need to know if this wire should remain connected. My guess is no, but I want to be sure I'm not affecting some other related system. This pin has 10.7V on it (curiously).
@mossman77 I assume you have answered this by now. In my research I'm concluding it's Switched 12V (B+) power. The remote in for the LC7i is spliced from this source in my install. I'm still battling white noise and grounding issues so I'm having to learn all this stuff since the audio shop could not solve it.
Quick question - did you every have to run all the grounds to the same bolt location or are they all separate?
@mossman77 I assume you have answered this by now. In my research I'm concluding it's Switched 12V (B+) power. The remote in for the LC7i is spliced from this source in my install. I'm still battling white noise and grounding issues so I'm having to learn all this stuff since the audio shop could not solve it.
I can't say for sure, but sounds plausible. I didn't use a remote wire. My Audio Control processor (and the LC7i) have GTO signal sensing, so you don't need a remote input connection. As stated earlier, you either need a processor with balanced differential inputs or an amplifier with balanced differential inputs (one or the other), and your noise will pretty much vanish. You still may have a little white noise, but you can adjust your gain levels to get rid of most of that.
I'm surprised you're getting that much noise if you're tapping off the output of the amplifier. I would experiment with the jumper settings inside the LC7i (Ground, 200 ohm, isolated). You could also try grounding the LC7i and aftermarket amp to the same point as the factory amp to see if that helps.
Quick question - did you every have to run all the grounds to the same bolt location or are they all separate?
I grounded my aftermarket processor and amp to the same point, but not to the same point as the amplifier (because I'm tapping off the amplifier input, not output).
@mossman77 yes the noise stops when I disconnect the RCAs from the amp. I went back all the way to the headunit and disconnected connector A which feeds the factory amp and the noise stopped.
@mossman77 yes the noise stops when I disconnect the RCAs from the amp. I went back all the way to the headunit and disconnected connector A which feeds the factory amp and the noise stopped.
Okay. Now disconnect the high level inputs from LC7i with the RCAs connected from LC7i to aftermarket amp. If still no noise, then it's either the factory amp, factory low-level audio inputs, or the head unit. The low-level audio wires running from head unit to factory amp are balanced and shielded so they shouldn't be picking up any noise, and if you didn't have any noise with the factory system, then something has to be going on with your grounding scheme between factory amp, LC7i, and aftermarket amp. Experiment with the LC7i internal jumper settings and see what happens.
I'm subscribed to this thread, so you don't need to tag me.
Thanks. I disconnected the speaker inputs from the LC7i and the sound goes away. I replaced the factory amp and no improvement (although the “new” factory amp still had a manufacture date of 2013). I was thinking maybe worn capacitors.
I also removed the remote in and turned on the GTO. No change in hiss.
I did notice the audio shop did something quirky. They spliced into the ground from the factory amp and routed it to the LC7i ground input but also left it going to the bolt in the trunk G653 i think. They also added a new ground wire from the LC7i to a different bolt. I removed this short ground wire from the LC7i as it didnt make sense. Now both the LC7i and factory amp ground go to the same bolt. No change in hiss.
The factory head unit is grounded to a bolt under the front dash and the aftermarket amp is grounded to a bolt under the rear seat so i still have three separate grounds.
One thing I forgot to add is when the auto door locks click I hear a brief click in the speakers. May indicate grounding issue.
Im thinking my next move will be to move the aftermarket amp and head unit ground to the bolt in the trunk - the latter will be a pain and Ive got to figure out what size ground wire to use.
Thanks. I disconnected the speaker inputs from the LC7i and the sound goes away. I replaced the factory amp and no improvement (although the “new” factory amp still had a manufacture date of 2013). I was thinking maybe worn capacitors.
I also removed the remote in and turned on the GTO. No change in hiss.
I did notice the audio shop did something quirky. They spliced into the ground from the factory amp and routed it to the LC7i ground input but also left it going to the bolt in the trunk G653 i think. They also added a new ground wire from the LC7i to a different bolt. I removed this short ground wire from the LC7i as it didnt make sense. Now both the LC7i and factory amp ground go to the same bolt. No change in hiss.
The factory head unit is grounded to a bolt under the front dash and the aftermarket amp is grounded to a bolt under the rear seat so i still have three separate grounds.
One thing I forgot to add is when the auto door locks click I hear a brief click in the speakers. May indicate grounding issue.
Im thinking my next move will be to move the aftermarket amp and head unit ground to the bolt in the trunk - the latter will be a pain and Ive got to figure out what size ground wire to use.
cu
Nice work. I'd be curious to see if the noise goes away if you remove the head unit ground to the same point as everything else inside the trunk. I'd also try connecting all grounds directly to the car battery. You could use speaker wire to do so, since it will only be temporary. Just be sure your gains/volume is turned down so you don't fry a wire/start a fire.
11-12-2016, 08:10 AM
