[A4] Radio Noise

Mitchell Segal MSegal at nsbgroup.com
Fri Jan 14 09:51:08 EST 2005

Hmmm, Bose amps.  I don't have the Bose option in my car, but I think in
looking at the wiring diagrams, I saw something that the left rear speaker
contains an Amp or some other circuitry, which then feeds the right speaker.
Seemed strange reading that, but I do remember seeing a lot of electronics
under the left speaker when I knocked the cover off one day.  If it is some
kind of amp, then it's right next to the rear window, so that might be
causing the interference.  

I think I'll try pulling the plugs on the rear speakers, and see if that
helps.  But something tells me that it won't matter, for the following

If you turn the radio on without anything else (key not in ignition), AM
radio is perfect!  As soon as you put the key in and turn it to the ON
position (without starting the engine yet), right away the noises start up.
So I don't think it's related to anything in the stereo system.  It's
picking up electrical noise from something else in the car, like the ECU,
ABS computer, or some other device that comes on when you turn the key to
on.  It's not the HVAC, as I have that off.  

What else turns on when the key is turned to ON, but not actually started?
It can't be the fuel pump, because that would run for a few seconds and then
shut off, since the engine isn't running yet.

I like your idea about the filters on the back of the radio.  My question to
you is, are these filters going on the Antenna lead in, or on the
power/ground lines coming in?

If it's on the Power lines, then which one?  Ground?  12v permanent?  12v
Switched?  I would be willing to try to install the filters myself, if I
knew what to ask for.  What do these filters look like?  Is there something
equivalent at the local electronics parts store?  A Capacitor/resistor or
something?  Do you know how to wire it?


-----Original Message-----
From: Larry Leung [mailto:larrycleung at gmail.com]
Sent: Friday, January 14, 2005 9:05 AM
To: Rocky Mullin
Cc: Mitchell Segal; quattro at audifans.com; a4 at audifans.com
Subject: Re: [A4] Radio Noise

My 89 200Q also has the antenna in the rear glass, but the static I hear
seems much more related to the Bose amps (doesn't respond to turn signals,
brake lights, etc.) than to radio noise, as it does occur in all modes. My S
car is TERRIBLE with static, picks up everything, (turn signals,
surprisingly not the wipers, turning on or off any of the lights, including
switching beams, rear defroster) but since it's not a
factory radio, not sure of the relevance. Doesn't appear that Audi did much
to isolate the leads to the head unit. What's stupid is your dealer could
probably stop your static issue with a commercial capacitance/coil in-line
filter and make you happy. Guess they're not willing to investigate enough
to try something Audi hasn't suggested themselves. Don't know the labor to
pull the head unit enough to install one of these generally less than $20 to
$50 filters (dependent on quality and current load ratings) but I'm sure
that they could still charge it to Audi. Heck, for the roughly $100 to keep
a customer loyal, they ought to do it anyway.


On Thu, 13 Jan 2005 23:05:56 -0800, Rocky Mullin <caliban at sharon.net> wrote:
>        it's too bad.  i love driving the A4.  so sporty, so damned
> tight.  like a GTI you can't spin out.  nowadays though, specs i need
> in a car include ground clearance and towing capacity.
>        sorry to rant.  it's interesting to finally hear of someone with
> the same radio problem, at long last!  keep me in the loop.

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