Engine noise coming through cigarette power adapter

[N6BY]

Do any of you guys with portable Sirius radios like the Starmate (not factory built-in) have engine noise coming in through the cigarette power adapter. It is very noticeable in the audio. I have a friend with this problem.

At first I thought the noise was coming in through the aux input line, but I have isolated the problem to the power.

The noise varies with engine RPM.

Anyone know of a solution? The only thing I can think of is to use a 5V USB charging battery to power the radio.

 

[Bobby]

I’ve seen this before but that was a long time back. There was something about the power cord and having built in suppression. I had bought a new radio and it got the whine. So, I used tge original wire and that fixed it. You might try a choke on the audio side. I think that will fix it. Amazon has something that could work and you might find something similar elsewhere like Best Buy or a local car audio shop:

Amazon product ASIN B0171PQLB8

 

[Inclined Orbit]

Much of the time the noise is due to a ground loop, or a difference in ground potential between the car radio and the accessory. In this case the shielded wires between the car radio and accessory (Sirius radio) try to equalize the ground potential and current flows on them, inducing noise into the low level audio cables. You can usually fix this by breaking the shield and bridging them with a reasonable value of non polarized capacitor which will pass the full frequency range needed. Or use an isolation transformer which has no DC continuity between its primary and secondary and will pass audio but not allow current to flow around it.

 

[N6BY]

Will try these fixes. Thanks!

 

[N6BY]

I’ve seen this before but that was a long time back. There was something about the power cord and having built in suppression. I had bought a new radio and it got the whine. So, I used tge original wire and that fixed it. You might try a choke on the audio side. I think that will fix it. Amazon has something that could work and you might find something similar elsewhere like Best Buy or a local car audio shop:

Amazon product ASIN B0171PQLB8

My friend said he just got this from Amazon and it completely eliminates the noise. Thanks again.

 

[Bobby]

My friend said he just got this from Amazon and it completely eliminates the noise. Thanks again.

Very cool! Thanks for passing that fix along.