How do you fix a ground loop - Audio Players & Recorders

Ground all electronics to the same connecting point, don't rely on grounds through equipment, or through the chassis , instead bring the ground from each to a single connecting point as close the the negative potential of the battery as possible. Make sure your ground wires are a heavy enough gauge so as not to create a large voltage drop between the actual ground and the equipment. The more current drawn by the equipment, the heavier the ground wire should be. Voltage drops occur on both the ground and the supply wires. When a ground wire is too small this voltage will vary with the current drawn, and you'll end up with a floating ground at the equipment.