New Inverter - Buzzing Speakers

My iMac is now plugged into a pure sine wave inverter to negotiate loadshedding. It seems to have introduced a buzzing to my speakers through a USB connected Modi 3 DAC. The buzz is there when no music is playing so I?m guessing it?s power related? The same USB cable and DAC into my MacBook plugged into the same inverter produces no buzzing. Not sure how to explain that, perhaps because it?s running off the battery even though it?s on charge?

Any suggestions? Could a USB cleaner of some sort help with this?

Would appreciate any insights!

Joe