Noise filter for 12v stereo system

[smittyjones]

So I bought this power supply to run a car stereo in my toolbox. Before I bought it, I emailed Jameco if it would work, he said

The power supply has more than enough to power a couple of LED Strips plus your car stereo. Just add some filtering circuit to stabilize the LED strips as well as noise filter for your stereo system. That should do it.

I don't really know what he means by filtering circuit or noise filter, so I though I'd ask here.

Everything works pretty well, but there's a little static through the stereo at higher volumes.

 

[Stuart in MN]

Switching power supplies like that one tend to have 'dirty' output voltages - if you were to look at the output with an oscilloscope it wouldn't be a nice flat DC voltage, it will have ripple and spikes in the waveform.

 

[smittyjones]

Is this something I can build myself, like is it as simple as an inline capacitor to normalize it or something?

 

[rockwithjason]

build a pi section filter. google it

 

[dogdog]

that's just another word for in-line stereo noise filters , they sells those or used to.... but mostly for interference cause by other electronics....


I think you just needed to find a largest capacitor you can get. Meanwell are good brand but some switching power supplies are just build to have soft start.... or limit the in-rush currents... it might not be able to actively handle the larger current demands when the stereo is at higher volume... I think that sympton happens on my friend's car amp when I hook them up... noise cracks at deep base at high volume.... but he was too cheap to spend on the larger capacitor (way then was expensive) or paying for another battery / isolator setup... so he ended up upgrading the alternator to a high amp ones.

 

[ctfjr]

that's just another word for in-line stereo noise filters , they sells those or used to.... but mostly for interference cause by other electronics....


I think you just needed to find a largest capacitor you can get. Meanwell are good brand but some switching power supplies are just build to have soft start.... or limit the in-rush currents... it might not be able to actively handle the larger current demands when the stereo is at higher volume... I think that sympton happens on my friend's car amp when I hook them up... noise cracks at deep base at high volume.... but he was too cheap to spend on the larger capacitor (way then was expensive) or paying for another battery / isolator setup... so he ended up upgrading the alternator to a high amp ones.

If the noise is a high frequency component from the power supply a large capacitor isn't going to do much. Ferrite cores are readily available. They look like donuts. You can take your power lead and and wrap it around the circumference of the core. You can google it. Here is one that I found in a second of searching: http://audiosystemsgroup.com/SAC0305Ferrites.pdf

Good luck

 

[dogdog]

read this if you want very informative.
https://en.wikipedia.org/wiki/Switched-mode_power_supply