Buzz Coming From Speakers

[Champak]

I just set up an aux input on my 94 LS400 for my laptop. When I'm powering the laptop through the lighter socket via an inverter, I get a hum/buzz sound with the audio. It doesn't happen when the laptop is running off its own battery. Is this due to the inverter it self, or the power coming out of the lighter socket? Basically will I resolve this problem by getting a standard car adapter for the laptop? Also, I was told if I put a suppressor in it will solve this, is that true?

Help please.

[hawkshaw]

It could be from a poor-quality converter but it could also be from a "ground loop." A ground loop is created when two items are grounded at different points where there is a small potential difference between those two points. This will cause the voltage difference to flow between those two devices which may become audible as hum.

Here's the Google search results for the term.