Quoted from Rager170:Its the box that connects the 3.5mm line. Looks something like this.
But im surprised that would cause voice issues and such. Ground Loop Isolators are to keep humms and static noises out of speakers. [quoted image]
I replaced the old one in my WOZ RR that originally came with machine with this, fixed all my audio problems so far. The volume would go up and down, sometimes just stop, and also weird static/humming, all gone now.