The CXX series amplifiers have two different ways that you can get a signal into it. One is called low level input and the other is called high level input. A low level input is measured in voltages. It comes in the form of RCA outputs from the back of your receiver and goes to the RCA inputs on your amplifier. A high level input is measured in wattages. It comes in the form one positive and one negative wire from the back of your receiver to and goes to the input terminal of your amplifier in the same wire form. Low-level (RCA) input wiring is preferred for best audio performance. Always use a high-quality RCA cable for best audio performance. NOTE: Do not connect BOTH the high level and low level inputs from your receiver to your amplifier at the same time.

Properly setting the gain on your amplifier is key to getting great sound in your car. The gain control is not for adjusting volume. It simply adjusts the amount of signal that is coming from your receiver and going to your amplifier. If you set it too high, you are introducing distortion into the sound. But if you set it too low, then you are choking back on what the amplifier is there to do.