120V inverter causing noise with laptop playing

Hey guys, I’ve got plans to place a monitor in the dash and run it with a PC.
I’ve plugged my laptop sound output to my alpine headunit aux input and the sound is great.
When I plug the power inverter and charge the laptop while listing to music, there is a loud noise, seems like an impedance mismatch OR some harmonics of the alternating 120V.

Anyone know how to solve my problem ?

i think i used to have the same problem. i used a ground loop isolator (without even grounding it) and/or a noise filter between the notebook and amp. only a bandaid fix, but it worked. i guess if i were you, i would first try another inverter. i was using a cheap one from fry’s, that eventually started making its own buzzing noise and could barely support anything. next figure out which ground in the path of the system/cig lighter to re-ground.

oh ya and when my system got jacked, they must have done something to cause a short in my jvc kd-sh99, because after that day, plugging in the rca’s without the filter/isolator would cause the amp to blip and shutdown.

i know it won’t be easy but at least you know it’s either a device or ground. good luck.

I cannot really use a ground loop isolator with RCA because my alpine deck has its own aux cable (alpine connector to 3/16 male adapter), no RCA.

I red somewhere that grounding the output (alternating 120V neutral, do not mix with Live!) to the negative terminal of the 12v battery (also the grounding point of the inverter’s inlet) would stop that noise, true ?

sorry i have no idea. that’s getting beyond my diy technical knowledge. time to whip out some engineering books or hit the audio message boards. you can start with these



that oughtta keep you busy for a few decades :stuck_out_tongue:

Thanks a lot man, from what i’ve red, i need to get a TRUE SINE WAVE inverter, which is double the price.
Conventionnal inverters create a squared sine wave which is fed through the computer and causing this noise…
Anybody else experienced inverter noise in speakers ???

I have installed a lot of them, mostly for game stations but a few as power supplies for other things including laptops, and as you have already found out yourself, it’s always the cheap ones that give me some kind of problem :stuck_out_tongue: 94