The adapter is not intended to remove the ground altogether. Note the tab? That’s for attaching to a new ground. The purpose of the adapter is to provide ground when outdated power outlets do not. The risk may be minimal, but I felt some clarity and caution were warranted.
Here are some more detailed notes about how to avoid ground loops in a music studio:
But if you aren’t hearing the noise from the speakers, and are instead hearing it from the grid itself, you might be encountering this?