Amplifier: Description and Operation

Fig.2 Amplifier:

The optional Infinity premium speaker system includes a separate Infinity audio power amplifier. This Infinity amplifier is a four channel unit rated at 25 watts per channel, or a total rated output of 100 watts. The amplifier unit is located on the rear floor panel underneath the left end of the rear seat cushion in the passenger compartment. The amplifier unit can be accessed by pulling the rear seat cushion release strap and folding the rear seat cushion forward against the backs of the two front bucket seats. The amplifier is secured to the rear floor panel with three mounting screws, which are installed from the passenger compartment side of the rear floor panel.

The amplifier circuitry is housed within a black painted, extruded aluminum housing with external ribbing. The amplifier housing is designed to aid in the dissipation of heat that is generated by the amplifier circuitry during normal operation. Four integral mounting brackets are used to support the amplifier, two located at the rear side of the housing and two located on the front side. The front inboard mounting bracket features a rubber bumper that rests against the rear floor panel when the amplifier is installed. The remaining three mounting brackets are each secured with a screw to the rear floor panel.

The Infinity audio power amplifier cannot be adjusted or repaired. If damaged or faulty, the entire amplifier unit must be replaced.

The audio power amplifier electronically increases the frequency response of the normal audio signal output from the radio amplifier in order to improve the acoustic performance of the speakers within the vehicle. On vehicles equipped with the audio power amplifier, the amplifier of the radio becomes a pre-amplifier.

All of the amplifier inputs and outputs are connected to two take outs and connectors of the body wire harness on the left side of the vehicle through two connector receptacles located on the left end of the amplifier housing. The amplifier receives battery current through a fuse in the Power Distribution Center (PDC) at all times on two separate fused B(+) circuits. The amplifier is grounded through two separate ground circuits and take outs of the body wire harness on the left side of the vehicle. These two take outs have a single eyelet terminal connector secured by a ground screw to the top of the rear seat riser located on the rear floor panel, just forward of the mounted amplifier. The internal circuitry of the amplifier switches the unit ON or OFF based upon a signal controlled by the radio power switch. The amplifier receives this signal through the radio 12V output circuit that is energized whenever the radio power switch is turned ON.

The amplifier receives audio signal inputs for four speaker channels from the radio, then sends amplified audio outputs through four separate channels with dedicated feed (+) and return (-) circuits to the six individual speakers. A front door tweeter and a front door speaker each share their respective amplified left or right front channel outputs from the amplifier. The front door tweeter and speaker are connected in parallel, using circuit splices to connect their respective right or left channel feed (+) and return (-) circuitry.