[rightaway]

I read on here and have been ready on here about a humming noise coming from the speaker. first I had an Alpine PDX amp, speakers hummed, everybody said to go with a jl 600/6, speakers still hummed even with the input sen turned all the way down. now I plug the factory amp back in, no humming/white noise coming from the speakers. I have a technic harness so everything is basically plug and play what am I missing?

also the door chime and Bluetooth is only coming through the back speakers. but the music comes from all the speakers

[tdgesq]

1) What is your stock system (base, hifi, top hifi)?

2) What other aftermarket components are you using besides the amp (signal processor, DA2, Cleansweep, etc.)?

[rightaway]

hifi, I don't know what top hifi. stock everything else except for sws under the seat. I have cdt door speakers but waiting on putting them in until I fix this problem.

[tdgesq]

Top hifi is the Logic 7 system here: http://www.e90post.com/forums/showthread.php?t=641323

So if you have hi-fi. The XD 600/6 has differential-balanced inputs, so that isn't the problem. You are going to need to isolate and diagnose. I'd start at the JL amp and see if you still get the noise without the rca's being plugged into the inputs. If unplugging the rca's stops the noise, then I would replace the rca cable itself that is running to the Technic Harness.

[ctuna]

If you can play a mp3 player or some other source through the
amp noise free its likely your radio . One guy even verified the harness
wasn't the noise problem by injecting a music source to the radio
connection harness at the radio . Swapping a radio is the logical thing
to do but not many have a spare lying around.

[bmw325i]

Why bother with the stock headunit? Unless you have iDrive you might as well just get a double din. If you have iDrive you should get a da2 and code to logic 7.

[rightaway]

i don't believe its the radio because I plug the stock amp in and it goes away. I have a non idrive radio.

[rightaway]

I unplugged each rca and it still has humming/white through the speakers.


will having the input sen turned all the way down effect the sound quality?

[tdgesq]

What that means is that it isn't the input signal that's making the noise. It's the amp. Since you had this same problem with a previous amp, I suspect you have a faulty connection to or from the amp.

Ime 90% of amp noise issues are related to a bad ground. Try changing the ground point. Also double check all of the rest of your connections. Make sure you aren't running a remote power wire into the speaker outputs on accident, for instance.

[rightaway]

remote is right. I'm using the ground on the driver rear fender mount that I see other people use. Is that a good point?

[tdgesq]

What I mean is, check all of the connections from the harness to the amp to make sure they are correct. Don't rely on the color of the wires. Use the pin out diagram that Technic sent you with the harness.

As for the ground, try the spot shown in this build thread first: http://www.e90post.com/forums/showthread.php?t=911595 It's about ten pictures down or so. If that doesn't work, run it all the way over to the negative battery terminal and test it there.

Btw, what gauge wire are you using for the ground? What is the length of the cable run?

[bmw325i]

Make sure the RCA cables are as far away from any ground and power cables as possible. How did you set your gain?

[tdgesq]

It's not the rca cables. The noise is present without the rca cables attached.

[bmw325i]

Originally Posted by tdgesq

It's not the rca cables. The noise is present without the rca cables attached.

How high did you set your gain?

[rightaway]

gains are turned all the way down.

[taibanl]

Originally Posted by tdgesq

It's not the rca cables. The noise is present without the rca cables attached.

That leaves you with power and ground or a defective amp

[tdgesq]

Originally Posted by taibanl

That leaves you with power and ground or a defective amp

It's not a defective amp. The OP states that he had the same humming sound with his previous amp. It's most likely a ground issue. He needs to switch ground points.

[taibanl]

Originally Posted by tdgesq

It's not a defective amp. The OP states that he had the same humming sound with his previous amp. It's most likely a ground issue. He needs to switch ground points.

Understood. That was noted. My post was more specific to indicate that with RCAs disconnected, those are the only two possibilities whatsoever.

[bmw325i]

Originally Posted by tdgesq

It's not a defective amp. The OP states that he had the same humming sound with his previous amp. It's most likely a ground issue. He needs to switch ground points.

Its also possible that both amps are defective. Not likely though, I would guess that it is the ground as well.

[rightaway]

Originally Posted by tdgesq

What I mean is, check all of the connections from the harness to the amp to make sure they are correct. Don't rely on the color of the wires. Use the pin out diagram that Technic sent you with the harness.

As for the ground, try the spot shown in this build thread first: http://www.e90post.com/forums/showthread.php?t=911595 It's about ten pictures down or so. If that doesn't work, run it all the way over to the negative battery terminal and test it there.

Btw, what gauge wire are you using for the ground? What is the length of the cable run?

4ga wire and I have my ground and power ran like yours

[tdgesq]

That's not my build. My ground is at the ground point for the negative battery terminal. Run some 4 ga to the negative terminal and see if that fixes it.