New inverter feeds back worse

[ChianaRiver]

I live off grid and recently changed my pure sign wave inverter, now I have three times the feedback noise in my system. The noise comes through both 12v, and 115v, power supplied. I had a cheep feedback eliminator that took care of 90% of the noise before. Now is much louder and the feedback eliminator only cuts half the noise. Is there a reference as to what power inverters produce the least feedback in audio systems? I have a basic home audio system that uses 3.5 stereo jacks, what is the best noise eliminator? Would grounding my RV to a copper rod help?

I love living off grid, with the nearest cell tower 5 miles away! So no RF inundated, mold-minded, grid-monger responses, thank U!