Noisy DC to AC invertert??

I expect the noise you are getting is from the cheap kind of inverter commonly available in home improvement and auto parts stores. The output waveform on the inverters os what is called a modified sine wave, which is really nothing more than a multi-step square wave. Most electronic devices REALLY don't like this kind of power, but they are almost ubiquitous. You need to look for a higher quality inverter, it will be larger, WAY more expensive, and not as efficient, but you need to find one that is SPECIFIED as true sine-wave output. They do exist, and a 300 watt version will probably cost between 75 and 150 bux. A quick search on the internet in yahoo, found this page. Otherwise I just used these keywords: 300 watt sine wave inverter, and got hundreds of results.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."