[sdiy] (OT) buzzing in my car cig-lighter...

[media at mail1.nai.net]

At 1:24 AM -0400 04/25/01, Reverend djbluE (Chromatest) wrote:
>
>I also use a cigarette lighter power adaptor to power the CD player,
>unfortunately, this introduces a buzz (ignition noise prolly).  when
>powered by batteries it is gone, but as soon as I use the adaptor it's
>there... so.. I don't actually have a cig lighter though, never had
>one, don't smoke, etc... is there a way to put a filter on the lighter
>jack?  a couple caps and resistor to smooth the line or something?

Yes, and they sell power filters specifically for car stereos -- you can
buy them from Radio Shack.  You can also buy "cigarette lighter" jacks.  If
you have a very old car, you can even add various coils and caps to your
ignition to reduce the noise -- that used to be a common practice.

>I don't know if it matters, but the line is independant from the
>ignition.. it's live even if the key is off.

Yes, cigarette lighters are always on in most cars.  Car stereo installers
usually tap it for memory back-up, however you don't want to power the
stereo from such a source, as forgetting to turn off your stereo can drain
the battery.