# Noise from speakers when head unit is switched off!



## KingMarty (Jul 18, 2012)

I have noticed something strange with my 2007 TT which I very recently acquired (today!!  )...

I was driving with the Audi Concert head unit on (it has the BOSE audio upgrade) and decided to switch it off so I can listen to the 3.2 V6. Then a few hours later, when I started the engine, I could hear a very low crackling/ringing noise which seemed to be coming from the speakers on the dash. Sort of sounded like static, for example when you have an untuned radio channel on, but at very low volume. I thought this was strange, as the head unit was still off (doesn't automatically come on if you previously manually switched it off). I then flicked the headlights switch to sidelights as it was going dark and there was a loud 'pop' through the speakers, after which the cracking/ringing static noise was no longer there. I switched the sidelights off, still no noise. Strange I thought.

However, next time I started the car, the same thing happened. Static type noise despite head unit being off, loud 'pop' when I flicked the headlight switch to the sidelights setting, then no more noise.

Has anyone else experience this? Any ideas as to what I should do? Thanks guys, and sorry for the loooooong post.... I have a habit of going on. And on. :?


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## igotone (Mar 10, 2010)

It sounds like some sort of short on the speaker circuit is causing a live circuit - shorting across a live wire somewhere . Could be a nightmare to trace a fault like that. Your best bet might be to have an auto electrics specialist have a look at it.


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## the minty1 (Mar 27, 2011)

If you got it from a garage get thrm to look at it. Otherwise, could be tricky. If the radio is switched off for sure, ie not lit up you should get no sound thro' the speakers as the radio turns on the amp which puts the sound to the speakers.


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## TT-driver (Sep 14, 2010)

I hear my speakers plopping too even after ignition is switched off. I don't have Bose installed. It seems as if the amp switches on shortly after I open the door. I don't know if it's normal behaviour. I can hear it more clearly ever since I installed an additional sub woofer.


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## KingMarty (Jul 18, 2012)

I got it from a private seller and am still very happy with the car, would have bought it even if the issue was present during the test drive etc. But it seems intermittent.

The head unit was completely switched off, no lights etc. Which is why I couldn't understand why there was 'crackling/static' coming out the speakers. Could be an issue with the GSM hands-free, the mic picking up interference maybe...

Later I switched the head unit on and put a CD in, seemed to work fine and sounded pretty good. Crisp punchy base, clear vocals (I listen to Hip-Hop mainly) - everything working as I expected. Anyway, I switched off the ignition so the unit went off. Then when I switched the ignition on next morning, there were no 'crackling/popping' issues, the head unit came on, CD started playing from where it was left etc. All good.

However, the next two times as soon as I switched the ignition on, the speakers made a loud/sharp 'pop' type noise (the head unit was coming on but the CD hadn't started playing yet)...

Something is definitely shorting somewhere. I suspected an amp problem, but initially the whole system was completely switched off, so it shouldn't have been on... :?


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## zip it (May 28, 2012)

Don't know if it's related to your problem but I have crackling when turned off, but then I also have rear speakers that don't work, and my base is working one minute and then off the next. This is down to a knackered Bose amp. I've removed it recently to check, and it's moisture damage.

Not an uncommon problem with the Bose amp.


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## TT-driver (Sep 14, 2010)

KingMarty said:


> ... but initially the whole system was completely switched off, so it shouldn't have been on... :?


I'd agree. However as soon as you open the door some circuits in the car spring to life. See the odometer and interiour lighting, but also the electric fuel pump that starts building pressure.

Now I'm wondering if this coming to life actually causes a change in voltage that subsequently triggers the amp to switch on too. Once the amp is on, any change in voltage results in a plop in the speakers. When I switch my head unit off, lock the car and come back an hour later or so to open it again, then I hear the plop and the amp in my sub woofer (which is triggered by input signal) has come to life too. When I leave the car alone, it all switches off again, until the next electric event happens. Then the amps are back on.


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## wasgezellig (Dec 18, 2012)

I have exactly the same problem as described above. I think in my case the problem was caused by a water leak. Sometimes I had no problems, but suddenly it was back. After a while I discovered that the problem occurred each time after washing the car. I discovered that there was indeed a fair amount of water in the boot near the battery. The leak has been resolved by now, but the problem is still not 100% gone. It is becoming less, but still not what it should be. Also, I still see the following error in the VCDS log. I will soon (if the problem is still not resolved) check all connectors to water.

Address 47: Sound System Labels: 8J0-035-223.lbl
Part No SW: 8J0 035 223 D HW: 8J0 035 223 D
Component: J525 Amp High H03 0150 
Revision: PROD_01 Serial number: 00000000200826
Coding: 0246116
Shop #: WSC 00096 211 184986
VCID: 254138DEECC10430723

1 Fault Found:
16349 - Control Module - Error in Output Stage 
014 - Defective
Freeze Frame:
Fault Status: 01101110


Is your problem completely solved? Possibly you can share what was the cause. Maybe it helps me and others to resolve the same problem. If your problem is still not resolved, then this information may be useful for you.


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## TT-driver (Sep 14, 2010)

Welcome!

You may want to check the internals of the Bose amplifier. I've seen pictures before of amps damaged by water on the inside.


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## moro anis (May 27, 2010)

I believe the HU and amp power up on opening the drivers door and stay on for 20 or 30 minutes after the ignition is turned off.


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## AaronWhite (Aug 29, 2014)

Guys, I've been searching and posting ref the same problem on my 2010 Roadster which is doing my brains in - Sorry to dig this up again today but any ideas King Marty? Did you find the source of the problem? Or anyone else???

Really appreciate any help

Thanks


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## rallybluecelt (Aug 29, 2015)

Hi

I too have a crackling TT...started the other day while listening to A CD (Thin Lizzy) . Switched it off and crackling continued. Parked up and cut the engine, removed key and the crackling could still be heard.....Later noticed if I put my foot on the footrest, the crackling gets worse. No problem with the radio/CD - nice and loud etc.

Broken wire? Thought I'd ask before getting the tools out and having a look!

Ok got my toolbox out and found the wires from the door had slipped down and were touching the metal cage the footrest sits on. I moved the wires up and gaffer taped them to the bulkhead, crackling stopped and the door speaker (previously not working I was told by my wife...after I'd sorted it) worked perfectly. Gets very loud that unit


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