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View Full Version : RF hum and vibration issue on B6 A4 with Bose...



AustinQuattro
10-02-2009, 06:35 AM
On a B6 A4, the sunroof control with the lights, there's a little vent on the part that is closest to the rear of the car. It’s the width of the assembly up there and about an inch long. When bass of any strength comes out of the radio, it vibrates noisily. If I push on it lightly with my finger, the vibration stops.

Does anyone know if maybe putting some wheel balancing weights on the inside would deaden it enough to keep it from vibrating?

AND, when I turn the car on, there is a hum from the speakers that gets louder as the RPM’s increase. It’s obviously RF noise from installing the amplifier. My question is, how do I get rid of it? I ran the power (with MattDevo) from a distribution block under the dash, under the carpet, up through to the amplifier. The ground is short, and grounds on the body underneath one of the seatbelt bolts. We tapped into the BOSE amp in the passenger side of the trunk for the signal and the remote turn on. The hum is present whether the radio is turned on or not. Would anyone know how to get rid of this? Is the ground not sufficient? Thanks in advance for any help.

b6onboost
10-09-2009, 11:16 AM
1. Stick a penny between the headliner and the plastic. Noise will stop. Since this isn't a permanent solution, be creative and find something else you can use in its place that will not be visible. A thin shim, piece of foam, ect will work.

2. Ground loop. I just had this problem. If your main ground(s) is good the problem is the RCA patch cords between electrical components are causing a ground loop. The ground loop causes the alternator whine to be outputted through the speakers via the RCAs.

Use a ground loop isolator on your RCA cords and the problem will go away http://www.crutchfield.com/p_127SNI1/PAC-SNI-1.html?tp=2653&tab=detailed_info