Hi,
I installed in my E500, a Sony CDXC910 head unit and Alpine MRVF307 4x30 amp in the trunk (gratitude to me ol' mate Curcio for helping me get through this...).
Unfortunately, there is noise in the system. With engine on, but head unit OFF (only clock display active), there is a nasty buzz, which changes pitch when vehicle moves from park to drive and when one switches on headlamps.
With engine on and head unit on, the buzz disappears, but pure noise appears.
I routed RCAs down driver side of car, power cables to head down passenger side and grounded head and amp at the battery ground location in the trunk.
Amp receives remote turn on from head unit remote trigger as does antenna.
Finally, I have hardwired a Valentine radar power cable. The little power connecter box is located under and between the seat heater switches and power is obtained from the cigarette lighter. The cable is currently coiled and unused under the carpet since I have yet to complete installation of the Valentine.
Any ideas as to what I should be looking for to eliminate the noise, especially the buzz when the head unit is off???
Thanks much
farrukh

Check to see how close the RCA's are to the power wire.

What kind of RCA's did you use? High quality nicely shielded ones or really cheap ones?

Check ground, and double check the ground.

What size power cable did you use and was it high quality and or well shielded..

Are there other power wires where you ran the RCA's?

Did you try maybe running the RCA's down the passenger side and the power down the driver side?

Check the Radio's Ground.

You can also at the battery use wire wrapped magnets in line of the power connector to see fi that helps with noise. I have seen it done on other cars.

try an RCA noise supressor as a last resort...

Alon

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'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon