Car Radio Noise Eliminator





Introduction: Car Radio Noise Eliminator


This is absolutely necessary:

1- Disconnect car battery because a small spark might cost you allot

2- Wear safety goggles. Your eyes are far more important than whatever you want to achieve

3- Preferably to wear electrician gloves

Step 1: Noise in Car Radio..drill in My Brain

Recently changed car alternator (charger motor). New part was costly, so it was agreed to install a rebuilt alternator with only 6 months warranty. Should be enough if the car is not intended to stay in the house longer.

Seems that rebuilt was not a good job. This was causing a buzzing noise into the car radio. It goes faster and slower as you press the accelerator.

This is a common issue in used cars.

trying to buy the noise filter. It was costly also. By doing some research (God bless google again)

Step 2: Material List

1- Toroid coil harvest from any switching or desktop power supply

2- Ceramic capacitors 2 pcs with high voltage rating. I experienced with different values this value worked fine: 105K/450 (which is 1uf with 10% tolerance and 450 Volt rating)

3- soldering iron, wires

solder the circuit as shown above in the simple schematic

One can flip the input- output but must make sure the battery +VE supply goes through the coil to filter the noise

Step 3:

solder them together

pics show from both sides how it is soldered.

It is a good idea to test the capacitors before using them. Some caps die from unemployment & sleeping in your drawer.

Step 4: Incorporate the Filter in the Car Radio Harness

take the car radio harness, cut the +VE supply line and connect the filter in between.

do not forget to connect the earth with earth of car.

Make sure to insulate this filter inside a small temperature-tolerant plastic box to avoid any short circuit.

Now turn on the radio and enjoy country music again.



  • Sew Warm Contest 2018

    Sew Warm Contest 2018
  • Gluten Free Challenge

    Gluten Free Challenge
  • Minecraft Challenge 2018

    Minecraft Challenge 2018

We have a be nice policy.
Please be positive and constructive.




Hey there! I didn't see the old pic so I have no reference to which I can compare your new pic, but it all looks just fine to me.

Even better, the instructable itself seems to very capably fill in the most important specifications:

1) It solves a common problem - especially one that's often expensive to fix;

2) It seems super-easy (that is, if you're familiar with simple electrical DIY - even more so if you've already opened up a car dashboard);

3) The necessary components are cheap, and common enough to find around one's home;

4) It's clearly and concisely written;

5) It has clearly focused, well-lit pictures

Well done! And thank you very, very much for this simple solution to an annoying problem. When I get around to cracking open my dash in a few weeks I'll post my results.



hello i have replaced the old image with new image i took with my cellfon...please tell me if now good to go ??thx