# humming after stereo install, MKV GTI



## ubernik (Aug 4, 2009)

Hello all. I have ran into an issues i have not had before and hope you uyts can help

I just finished my full install on my mkv gti. Pulled out carpet, replaced all speakers, new head unit and 5 channel amp.

Head unit is pioneer AVH-P3200BT

Amp is a blaupunk THA-555

Here is the issue

When the car is running i get a slight ground loop noise ( high pitched and raises with RPM) ground loop isolators help but dont remove compleately)

Wierd issue is when i turn on my head lights, i get a another, louder hum, that does not raise with RPM.

Power wires is going down driver side of car, RCA down passenger. and they dont meet until the amp.

However, i did bundle the RCA with the factory wiring loom.

Is there enough juice in the wiring loom to cause issues with my rca.

this is my RCA

http://www.sonicelectronix.com/item_...r+SPI6317.html

does it not have enough shielding?

I have a JL 4 channel i can try buf dont want to pull the head unit unless i need to.

any help would be great


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## elrich_d (Aug 6, 2008)

hmm last time i did an install and heard the noise which went up with revs it was the rcas. Also check your ground that its at a good solid point. Did you just use one long rca or join them, if you joined them make sure the joint secure and not where people step on.


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## ubernik (Aug 4, 2009)

i used a single 17' 6 channel rca. I may pul lthe head unit and ground it to the chassis, as the ground is through the factroy harness right now.


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## hamfactorial (Jul 14, 2010)

I installed a Pioneer AVIC-Z120BT (build log here - http://forums.tdiclub.com/showthread.php?t=291028) and I had the same problem regarding ground loop / RPM whine.

I performed the nav/DVD bypass by using the Pioneer-provided parking brake clip (it's a red pinch-clip that I spliced into the mute wire + ground wire). After hearing the ground loop noise, I cut that out and re-soldered the bypass wires, which solved the RPM whine. I did notice, however, the same headlight humming.

I have a 4ga ground wire bolted to the rear seat hold-down, which I suspect is not getting a good connection. I have two distribution blocks in the trunk for +12V and -GND, and I've run dedicated power/ground lines to the head unit. I got the humming when connected to the factory harness, for what it's worth.

Like you, the power wires all run on the left side of the car. The RCA cables run on the right side. As a test, I ran RCAs through the cabin and over the seats into the trunk. In that configuration, the headlights still cause that same low-level hum.

If I figure it out, I'll reply here.


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## hamfactorial (Jul 14, 2010)

I just realized that you're Nik Brewer, cool! I bought a sub + box from you for my 2010 Jetta TDI


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## ubernik (Aug 4, 2009)

i hope you are enjoying the sub box

i plan on running a ground wire from the radio to where the amp is grounded. I have read this may cure this issue, ill try it in the next day or 2


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## Pat @ Pitt Soundworks (Nov 14, 2008)

Maybe this will help, maybe it won't.

About a year after the mk5's first came out I was brought a car with a noise problem. Aftermarket head unit and two aftermarket amps. Same thing as you, noise with the engine running and more noise when you switched through the accessories.

I tried everything
-common grounding of the head unit and amps
-direct power wire from the battery to the head unit
-wire direct from the common ground to the negative post on the battery
-grounding the RCAs on either end of the cable to the common ground

The only thing that solved the problem was lifting the power and ground wires to a second battery that was not hooked up to the rest of the cars electricals. As soon as I jumped the second battery to the first, bam, noise came back.

All I could really chalk it up to was alternator induced noise. Threw in three ground loop isolators and called it a day.

It was the only car that I had to put isolators in....


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## ubernik (Aug 4, 2009)

the isolators are not entirely fixing the issue either. I was looking af putting a power choke on the head unit, and common grounding to begin with.

Tons if guys have done systems in these, and i have not heard a lot of complaints. I am goign to try a new rca as well


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## hamfactorial (Jul 14, 2010)

Nik:

Did you ever get this issue resolved?


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