89 300se Aftermarket Radio Whine
 

I have asked this question before and still have not gotten resolved, but here it goes again. I have an 88 300se(w126) and I replaced the Becker radio with a Nakamichi receiver and sony xm radio. I now have a whine coming through the speakers and also a slight buzz. I had gotten some information previously on this board about having to change the ground wire from the factory and ground it somewhere else. I did so today and the whine did not leave. It is still there. So, I wired the deck back the way it was originally. The xm radio antenna runs along side the passenger side, so I unplugged the antenna to see if it would cut the whine out. It did not. Can anyone tell me what might be the problem? I am about to lose my mind over this problem. As you are driving the car, the faster you go, the higher pitched the whine. I hope someone else has had this problem and can tell me a complete solution. Thanks in advance.

Scott

If you haven't already, check the condensor (capacitor) at the alternator. Also make sure alternator is secure to it's mounting bracket (that's it's ground).

capacitor at alternator
 

Can you give me some details of what might be going on? What am I looking for? I can check the alternator and make sure it is secure to the bracket. Thanks.

Scott

This problem is most often caused by ground loops. The best way to fix it is to ground everything (head unit, amps, etc.) to the exact same point. If one of your units is connected to the factory ground that existed for your original head unit and the other is grounded somewhere else (as is typically done) it could be your problem. They should both be grounding to the same place. Do you have an external amp? If so, it should also be grounded to the exact same place.

whine
 

The factory ground, the radio itself, and the xm radio are all grounded together. Over the weekend, I seperated them and grounded them all different and it didn't make any difference. One person stated I needed to totally ground everything not using the factory ground. I did so and saw no change. I don't know what to do. I have not checked the alternator bracket like someone has suggested. The whine is so annoying. I treasure any suggestions and potential fixes.

The condensor is a one wire connector square black box (or tube, sometimes) on the rear of the alternator. Worth a check as this is what the engineers designed to help eliminate alternator whine.

When does the whine happen? When playing cd's, on radio, on xm?

Scott

whine
 

The whine starts as soon as you turn anything on audio-wise, whether it be the regular radio or the xm radio. As soon as you turn the power off to either the regular radio or the xm, the whine stops. You can drive the car with the radio/xm off in perfect peace. But, as soon as you turn one of them off, you pick up a whine that as you go faster in the car, the whine gets higher pitched. If you turn the volume up on the radio, the whine gets louder. Any suggestions?

Which is it? Both on = whine, either one off = no whine, correct? I ahve eliminated this on many vehicles successfully, but you have an interesting situation. Perhaps one of the head units is grounding through its chassis. What happens if they are pulled out, ie. not mounted in the dash, and both on? Are they touching each other when installed?

whine
 

I have run my xm radio throught the aux using rca's in the back of the deck. With the deck off, I can turn the aux on(on the deck) and the whine starts. Then, I can turn the power to the xm on and the whine still remains. With everything off, I can turn the power to the deck on to listen to the regular am/fm and the whine starts again. Anytime I turn either one on, the whine starts. I pulled the deck out of the dash(when I was experimenting with the different ground places) and the whine was the same as if the deck was mounted in the dash. All grounds from the factory ground, the deck ground, and the xm ground are wired together at the same place. As stated above, seperating these grounds did not make a difference. I even did as one person suggested and move the xm antenna wire(I actually unplugged it from the xm radio) and there was no difference. According to him, the power wires run along the passenger side of the car and sometimes with an aftermarket deck, there can be some feedback and you have to reroute the speaker/antenna wires to the middle of the car or the driver's side. But, in unplugging the antenna, there was no change.

I think that you have covered all the regular bases. If I were you, having eliminated all possibilities I know of, I woudl take it in to a car audio place and have it fixed. Try to avoid using a filter, but you could do that if you have to. Take a look at this web site as they have some nice stuff for specific problems. When I installed my Blaupunkt Powered Sub I discovered that my preamp outputs on my headunit were only 500mv. I bought a nice compact line driver from them to boost that signal to 4v (normal). It was very reasonable and I was surprised at all the products they offer. Anyway, good luck as I am out of ideas (sorry).

http://www.davidnavone.com/

One last thing I forgot, you should probably check the capacitor that jbaj007 mentioned. At least eliminate it from the equation - you never know.

Lets go back to square on. What components do you have make and model of radio and xm tuner and where are they located in the car? The first thing I would recommend is to unplug the sony xm unit from your radio and determine if you have noise still. If you don't then it would be fair to say it is coming through the sony's audio cable and there is more than likely a ground loop being created between the two components or the sony unit is picking up noise on its power line which can be filtered with an inline filter. You can also try grounding the shield on the rcas going into the auv input, to the radio chassis and see what difference that makes. Let me know what you find !

Scott@lajollaaudio