Just installed new head unit popping noise when changing inputs.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
Oh ok, well i noticed a few things just driving it the hissing only occurs when the engine is on there is no noise when i have the power on but no engine. Also the ground i ran to the chassis is actually a wire i slipped under a metal screw near the hood release, so basically its a screw pushing up against plastic is this a sufficient ground? Also when i turn the car on the beeps it makes are distorted sometimes.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
You will only get ground noise while the engine is running, so this would be normal to have no noise with the acc turned on.
Metal to plastic will not create a ground. I think if you add the amp ground to the bundle, the hiss will go away. Use the ground from the OE harness. once all the grounds are connected the noise should subside. The distorted beeps should not be related.
Metal to plastic will not create a ground. I think if you add the amp ground to the bundle, the hiss will go away. Use the ground from the OE harness. once all the grounds are connected the noise should subside. The distorted beeps should not be related.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
You will only get ground noise while the engine is running, so this would be normal to have no noise with the acc turned on.
Metal to plastic will not create a ground. I think if you add the amp ground to the bundle, the hiss will go away. Use the ground from the OE harness. once all the grounds are connected the noise should subside. The distorted beeps should not be related.
Metal to plastic will not create a ground. I think if you add the amp ground to the bundle, the hiss will go away. Use the ground from the OE harness. once all the grounds are connected the noise should subside. The distorted beeps should not be related.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
Just so we are on the same page, discounting the brown wires, you have a black ground wire coming from the harness to the left of the red wire nut. You have a black ground wire coming from the back of the head unit. Then you have a black wire running from that bundle back into the dash. Where is that wire going? Where is the ground wire you mention from the VWAmp?
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
Well I managed to get the noise gone (I hope). With this ground to chassis etc. But I guess if it's not one thing its another, now there is a noise when i turn my interior front lights on and off and the driver side one stopped working completely. I am not sure if this is related to the stereo setup or what but it sounds like the noise is coming through the speakers or interfering.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
I see you have other issues that may or may not be related to your install. A couple of questions.
Do you still have the ground loop isolators installed.
If so, try grounding the head unit to the isolators WITHOUT the factory ground coming from the harness. Also without the ground going to the chassis.
If still noise, try with the chassis ground, again no ground wire from the harness. Make sure you have a metal to metal contact. You may even want to run the ground wire to the engine bay through the firewall and get a metal to metal contact there. This needs to be a bare metal to metal contact. No paint. This is also the case to where ever you are trying to ground in the car as well.
Do you still have the ground loop isolators installed.
If so, try grounding the head unit to the isolators WITHOUT the factory ground coming from the harness. Also without the ground going to the chassis.
If still noise, try with the chassis ground, again no ground wire from the harness. Make sure you have a metal to metal contact. You may even want to run the ground wire to the engine bay through the firewall and get a metal to metal contact there. This needs to be a bare metal to metal contact. No paint. This is also the case to where ever you are trying to ground in the car as well.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
I see you have other issues that may or may not be related to your install. A couple of questions.
Do you still have the ground loop isolators installed.
If so, try grounding the head unit to the isolators WITHOUT the factory ground coming from the harness. Also without the ground going to the chassis.
If still noise, try with the chassis ground, again no ground wire from the harness. Make sure you have a metal to metal contact. You may even want to run the ground wire to the engine bay through the firewall and get a metal to metal contact there. This needs to be a bare metal to metal contact. No paint. This is also the case to where ever you are trying to ground in the car as well.
Do you still have the ground loop isolators installed.
If so, try grounding the head unit to the isolators WITHOUT the factory ground coming from the harness. Also without the ground going to the chassis.
If still noise, try with the chassis ground, again no ground wire from the harness. Make sure you have a metal to metal contact. You may even want to run the ground wire to the engine bay through the firewall and get a metal to metal contact there. This needs to be a bare metal to metal contact. No paint. This is also the case to where ever you are trying to ground in the car as well.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
So the radio whine from the speakers is gone? This is good. Just so I understand, this new noise is NOT coming from the speakers, but from the light itself? As for tapping the lighter, I am not sure it is worth the effort since there in no radio whine.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
Yea I took it to my mechanic for the light whine he couldn't hear it himself his son has the same and we found the same noise maybe my ears are overly sensitive. I was hoping the good ground would mean I could remove the isolators because I think they muffle the sound but as soon as u remove them popping returns anyway I can't imagine installation would be this intense mabye I just want too much.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
You can get rid of the isolators by getting a PAC OEM2 unit. This will boost and balance the signal. By boosting the signal, it gets rid of the pops when changing functions. On the other hand, since your particular install seems so sensitive to noise, maybe let sleeping dogs lie and call it a day.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
You can get rid of the isolators by getting a PAC OEM2 unit. This will boost and balance the signal. By boosting the signal, it gets rid of the pops when changing functions. On the other hand, since your particular install seems so sensitive to noise, maybe let sleeping dogs lie and call it a day.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
With the popping and ground noise, they felt the loop isolator would be the best solution, as the PAC OEM2 does not isolate the ground loop. By boosting but mostly balancing the signal, it keeps the head unit from making the popping sounds while changing functions. I am not sure why your system is so sensitive to ground noise. Could be the head unit or the alternator or voltage regulator, could be some corrosion on the ground strap etc., or maybe the PO screwed around, tried and failed to upgrade the system and ungrounded the amp. There are many things it could be, but you may never track it down.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
With the popping and ground noise, they felt the loop isolator would be the best solution, as the PAC OEM2 does not isolate the ground loop. By boosting but mostly balancing the signal, it keeps the head unit from making the popping sounds while changing functions. I am not sure why your system is so sensitive to ground noise. Could be the head unit or the alternator or voltage regulator, could be some corrosion on the ground strap etc., or maybe the PO screwed around, tried and failed to upgrade the system and ungrounded the amp. There are many things it could be, but you may never track it down.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
Yes and no. Remember, the Bose speakers are 2ohm. Most aftermarket head units put out 4ohm. So, if you are replacing the speakers and amp, as well as the head unit then yes it is a good option.
When you do this, you are using the head units internal amp. The impedance difference can cause the amp to run hotter, shortening the life of the head unit or causing it to overheat and fail altogether. Most likely senecio is the first not the last. If you do a web search, you will find many differing opinions on this subject.
Whether you go this route or not, it will not change the ground noise factor. You have noise coming from somewhere in the ground loop. Since I am not there I can't help determine where the noise is coming from, but if you or someone else could find the source, you can get rid of the ground loop isolators. This would dramatically clean up the sound getting rid of any muddy highs and lows you are getting. You would still however need a PAC OEM2 to boost the signal so you don't get the popping noises. Or, try another head unit with higher voltage output on the pre amp. This will address the popping noise, but you may still have the ground noise to deal with.
When you do this, you are using the head units internal amp. The impedance difference can cause the amp to run hotter, shortening the life of the head unit or causing it to overheat and fail altogether. Most likely senecio is the first not the last. If you do a web search, you will find many differing opinions on this subject.
Whether you go this route or not, it will not change the ground noise factor. You have noise coming from somewhere in the ground loop. Since I am not there I can't help determine where the noise is coming from, but if you or someone else could find the source, you can get rid of the ground loop isolators. This would dramatically clean up the sound getting rid of any muddy highs and lows you are getting. You would still however need a PAC OEM2 to boost the signal so you don't get the popping noises. Or, try another head unit with higher voltage output on the pre amp. This will address the popping noise, but you may still have the ground noise to deal with.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
Yes and no. Remember, the Bose speakers are 2ohm. Most aftermarket head units put out 4ohm. So, if you are replacing the speakers and amp, as well as the head unit then yes it is a good option.
When you do this, you are using the head units internal amp. The impedance difference can cause the amp to run hotter, shortening the life of the head unit or causing it to overheat and fail altogether. Most likely senecio is the first not the last. If you do a web search, you will find many differing opinions on this subject.
Whether you go this route or not, it will not change the ground noise factor. You have noise coming from somewhere in the ground loop. Since I am not there I can't help determine where the noise is coming from, but if you or someone else could find the source, you can get rid of the ground loop isolators. This would dramatically clean up the sound getting rid of any muddy highs and lows you are getting. You would still however need a PAC OEM2 to boost the signal so you don't get the popping noises. Or, try another head unit with higher voltage output on the pre amp. This will address the popping noise, but you may still have the ground noise to deal with.
When you do this, you are using the head units internal amp. The impedance difference can cause the amp to run hotter, shortening the life of the head unit or causing it to overheat and fail altogether. Most likely senecio is the first not the last. If you do a web search, you will find many differing opinions on this subject.
Whether you go this route or not, it will not change the ground noise factor. You have noise coming from somewhere in the ground loop. Since I am not there I can't help determine where the noise is coming from, but if you or someone else could find the source, you can get rid of the ground loop isolators. This would dramatically clean up the sound getting rid of any muddy highs and lows you are getting. You would still however need a PAC OEM2 to boost the signal so you don't get the popping noises. Or, try another head unit with higher voltage output on the pre amp. This will address the popping noise, but you may still have the ground noise to deal with.
Last edited by Dnasty; Apr 11, 2013 at 12:12 PM.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
Yes, 4volt is fine. I was under the impression your head unit puts out 2volt at the pre amp. If I am wrong and you are 4v at the preamp, you should not be getting the pops. Sound quality is subjective. I can't tell you if it will sound better or not. I can tell you that the level of volume will be less without the Bose amp. In other words if with the Bose amp your preferred volume level is 15, without the Bose amp you will need to crank it to 25 (as an example) to get the same amount of sound.
If your pre amp is putting out 4v and you are getting pops, there are other issues.
If your pre amp is putting out 4v and you are getting pops, there are other issues.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
It's definitely 4 volt I specifically went for this as I did a great deal of researching before purchasing. I even told the tech from crutch field this and he replied 4v is relatively low.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
In my opinion, 4v is minimum. I like 5 or better. Some say as low as 3v output is sufficient. I am afraid that at this point, without being able to put hands on you may need a professional to go over your install. I have done several of these, and many more Bose installs in other vehicles. Very few have had these problems, and were easily resolved.
Things to go over.
You are running a ground to bare metal at the chassis of the car. GLI should not be necessary to get rid of whine. Why whine without isolators.
Pops when changing functions. 4v pre amp output should be enough output to not have them. Personally, I have never done a Bose head unit conversion without a PAC OEM2 unit, so I am going by others that I Have seen who have done installs without it. You should not be getting the pops without the isolators.
These two issues are bothering me, and I can't give you good answers to them.
Things to go over.
You are running a ground to bare metal at the chassis of the car. GLI should not be necessary to get rid of whine. Why whine without isolators.
Pops when changing functions. 4v pre amp output should be enough output to not have them. Personally, I have never done a Bose head unit conversion without a PAC OEM2 unit, so I am going by others that I Have seen who have done installs without it. You should not be getting the pops without the isolators.
These two issues are bothering me, and I can't give you good answers to them.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
Yea just talked to crutch field again they are mailing me some PAC isolators (thought all gli's were pretty much the same) but ill give it a shot. Honestly bestbuy will install it for 60 bucks bypassing the Bose amp I just need to buy their harness I dunno if I should just let em do it and be done with it. My as is setup volume has to be almost max for good listening volume and 0-15 is considerably low... 35 being the highest.
Senior Member
Joined: Feb 2013
Posts: 320
Likes: 6
From: DFW
2 2001 E320s, 2005 E320 4Matic
PAC OEM2 IS NOT an Ground loop isolator. It is a line output converter. Do not mistake the two. Make sure they are not sending another GLI. The PAC boosts and balances the output from the pre amp. It will NOT isolate the ground.
Thread Starter
Super Member
Joined: Feb 2013
Posts: 862
Likes: 28
2010 e550 coupe
Yea I told em the situation I know the two are different. They actually discontinued selling the pac oem which is why i think they talk you out of it anyway its free so I told em go ahead and send it. Just to make sure i'm not being unrealistic with my expectations, in ideal circumstances will there still be audible noise coming through the speakers when the unit is on even if it is almost undetectable. Or should there be no audible difference between standby and cd/radio/aux mode when the volume is at 0?
