Thread: Technical explanation of inverter noise?

Just a quick comment.

anyone who has a modified sine invertor.

Plug your pc into the mains, and check the temperature of the PSU. Then do the same with the invertor.

You'll find that off the invertor it will probably run very warm to hot in comparison with the mains, some PSU's even "sing" when running off an invertor.

The problem arises because both the invertor and the PSU are both switched mode power supplies, and the harmonic noise from the invertor "annoys" the computer PSU (different switching frequencies).

Anyway, The Opus is cheap enough, buy one, they work!

You'll find that off the invertor it will probably run very warm to hot in comparison with the mains, some PSU's even "sing" when running off an invertor.

This is because the harmonics associated with a non sinusoidal inverter represent wasted energy. They have to be dissipated somewhere. If you can afford an Inverter with a sinusoidal output, buy it. If you can afford a DC to DC that will power your setup, that’s even better.

When I used inverter setup. I have NO audio noise, engine whine or any similar noise. The only noise that I can hear is one that coming from the AC PSU (harmonic). The only time I can hear that noise is when the engine is NOT running and totally silence. Once the music is play, there is NO noise cuz music is much lounder than that harmonic noise.

Originally Posted by numbers

Inverters tend to raise the chance of having a noisy system because of the fact that they put high voltage ac in close proximity to everything. The actual way that the noise gets to the speakers is that electromagnetic interference is radiated from the ac devices and wires and somehow finds it's way to audio wires. If the audio wires are too close, or if they have ****ty shielding, or if they are improperly grounded, they are more likely to pick up that interference and carry it to the speakers. Dc-dc setups also produce emi, but it is a fact that there will be more emi present around an inverter setup than a dc-dc setup. What it all comes down to is just how much of that emi is finding it's way into your audio cables.

Folks who say pure sine wave inverters are better for carpcs are saying that because they saw that someone else said it. That someone said it because he heard someone else say it.... I don't know exactly who first said it, but they're not entirely right.

Folks who blame their noisy setup on their inverter need to learn a bit more in the area of keeping emi out of their audio cables.

I am open to suggestions. I found placing random connections to the vehicles ground along the path of the audio eliminates msjority of the noise but not all especially when it comes to the microphone setup. As an example when I record audio using something simple like windows sound recorder I can hear the noise in the recording. Any help would be great.

Leo

P.S. I am no electrical engineer that is why I read these forums. I only know enough to hurt myself.