Intro: 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
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.