Audiophile PC ground loop issues?

Why is my speaker buzzing? Is it a ground loop? How can I fix it?

Atom™ - Ground Loop

[Hot Item] 3.5mm Plug Aux Stereo Jack Car Ground Loop Noise Isolator

iFi Groundhog+ Ground Loop Isolator for Audio Systems

Ground Loop Isolator Noise Filter for Car Audio/Home Stereo, 2 PCS Ground Loop Noise Isolator with 3.5mm Audio Cables

Is it safe to use a "ground lift" to break a ground loop when using two amps?

Closed Loop Analog Position Control using Brushed DC Motor and Potentiometer    - Electronics-Lab.com