Any ideas?

[Jakes21]

Hi there people.im stil learning about electronics.it really fasinates me what u can do.any how....i want to build something to cancel that zing noice my speakers make when my car is running...what ideas do u have?the powercables isnt near my RCA cable....thanx in advance.i do know a few stuff,build a few projects of my own so im not that clueless

 

[0x00x0]

You are probably talking about noise coming from the alternator, which is eaisly solved by isolating the radio from it, using a capacitor as a filter (at least is was for me)..

Might want to read this:
https://www.termpro.com/articles/noise.html

 

[Jakes21]

Thanx ill check it out and let u knw.

 

[Mikebits]

Also make sure your radio ground is a big beefy gauge wire. Check your connections on your car batt, alternator also. Resistive spark plug wires help also.

 

[Jakes21]

Okay i did put a 100uf cap on it and it went quieter...but i got greedy and at first i had a 0.47uf cap on it.just to listen what will happen but when i add the 100uf cap the (+) fuse on the Radio blew...mmm what happend..does it have something to do with the discharge of the 100uf cap?

 

[Boncuk]

Additionally you could move the positive supply line from the ignition circuit (wired through the switch) directly to the positive battery terminal.

That way the DC going to the radio is buffered DC by the alternator, and noise will be reduced to almost zero.

Also the ground connection should go directly to the battery.

Using the already suggested filtering methods there should be absolute silence with no station tuned (except for the noise the amplifier generates with no signal).

Don't forget to switch off the radio before you leave the car for a longer time period. Otherwise you might experience a surprise.

Boncuk

 

[Hero999]

Also the ground connection should go directly to the battery.

That's true, using the chassis as a return path may be an efficient use of cable but it's a nightmere for EMC which is why it's prohibited on many military vehicles, especially those carying explosives.


Adding ferrite beads to the power supply is also a good idea and keep the 470nF ceramic as it's better at high frequency filtering than ther 100µF electrolytic.

 

[Jakes21]

Whats the diffrence betwen the 2? Ceramic and electroletic? I knw electroletic u must connect + by +

 

[Hero999]

Ceramics are better at higher frequencies, have a lower series resistance and last longer than electrolytics.

It's possible that your 470nF capacitor is an electrolytic but it's more likely that it's a ceramic - values under 1:mu:F generally are.