The most common noises I hear of people having problems with in their audio systems are ground loops. Let me explain what these are. A ground loop occurs when the absolute ground voltage of one unit is different that that of another unit. When you have a difference in voltages, and an electrical connection between them, current will flow in the conductor. In our cars, we often get noise when we are using an amplifier with a head unit. The amp is grounded in the rear, and the head unit in the dash. Sometimes one connection is better than the other, and the difference in voltage flows through the shield of our RCA signal cables. Because it is so close to the signal itself, it is usually picked up by the amplifier and amplified to our speakers.

To prevent ground loops, there are several procedures that can be followed. The first and most important thing to remember when building a system is to provide a high-quality, noise-free ground path to all your equipment. The ground connection is even more important than the positive power connection, and most people overlook this. In my opinion, the ground cable for the audio system should be run exactly as the power connections. Large conductors front to rear, proper distribution blocks, etc.

Grounding should also be done in a 'star' configuration. Choose a central location for the distribution, and then run a ground to each and every component from that location and connect to your equipment.

The normal do's and don'ts apply as well:

  • Use large power conductors
  • Use high quality RCA cables
  • Make sure the system is level matched properly
  • Use a common ground scheme
  • Upgrade all relevant electrical connections (battery positive and negative, alternator positive and ground, etc...
  • make sure all connections to the chassis have ALL the paint removed

  • Use factory ground wires for anything
  • allow the power and signal wires to be close to each other or the factory electrical system.