Hey @Boneyard51 ! A ground loop would be multiple grounds stacked in one location . Or the same circuit grounded multiple times . If you have a back feed issue or weak ground , the signal or noise can back feed or loop through the redundant ground . when I worked on British junk , there where “ stacked grounds” and you had to make sure you put the grounds back the same way they came off the stud “ 1,2,3,4 ,5,6,7 NOT. 1,4,2,6,3,5 ,7 . If you did not stack the grounds correctly you could end up with a buzzing noise out of a controller or module , or lights not working 100% correctly. not a big deal on our junk . But on more sensitive electronics it becomes an issue, or if you have a “ boom boom” stereo it can pick up interference. You can actually buy “ ground loop isolators” to plug into your amplifiers to eliminate noises . you can google it for a better explanation then I can give you , but this is the gist of it .