SL55/63/65/R230 AMG Aftermarket amp noise problem!

Oct 7, 2019 | 08:28 PM

vnova94

Thread Starter

Junior Member

Joined: Aug 2014

Posts: 51

Likes: 0

2012 ML-350

Aftermarket amp noise problem!

I finally finished installing my aftermarket amp and speakers. Added a Rockford amp below cubby where Bose amp is located for subwoofer. Used the factory wiring. No issue....although I wonder if the factory wiring is sufficient. The amp doesn’t have a big draw. I then added my Adcom amp in the trunk. Used Stinger 8-gauge hookup kit. Grounded the amp to the chassis where the rear battery negative post attaches. When the car runs, I get a nasty whine in the system. I’d rather not add a ground loop isolator and would rather fix the ground loop. The head unit is grounded to the factory wiring as well. So I’m guessing there’s an impedance difference between the factory wiring ground and the chassis ground at the rear battery?

Any suggestions? Maybe run a ground cable connecting the factory ground all the way to the trunk ground?

thanks,

matt

Oct 8, 2019 | 09:32 AM

bobterry99

Banned

Joined: Jan 2006

Posts: 1,982

Likes: 393

From: Atlanta, unfortunately

'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55

Quote:

Originally Posted by vnova94

Maybe run a ground cable connecting the factory ground all the way to the trunk ground?

It seems to me that cable would have a higher impedance from the trunk to the head unit than the path through the chassis. So if you think the cause of the noise is impedance in that return path, then running a cable may make the problem worse.

In my extremely limited experience with car audio, noise characterized as a whine was caused by inadequately-regulated voltage supply, and it would vary with engine RPMs Filtering power to an amplifier with a parallel capacitance and possibly a series inductance as well was the fix.

Oct 10, 2019 | 09:30 AM

pmercury

member

iTrader: (2)

Joined: Oct 2016

Posts: 3,093

Likes: 807

Quote:

Originally Posted by vnova94

Hi Matt
I have the same problem, that wining sound following the RPM
never had time to go after it, I don't listen to music when I drive prefer the engine and tires music
let me know if solved
I was thinking about a filter

Oct 12, 2019 | 01:05 PM