The Audio Preamplifier

Today one gets the sense that all types of communication have chosen to convert to a digital system. Some digital equipment may have made its way into the sound system of the average automobile, but most of present-day cars still use an analog sound system. The requirements of an analog system dictate the construction of the audio power amplifier and the audio preamplifier.

The audio preamplifier has several different functions. Its primary function concerns conversion of the sound information carried by the audio system’s electrical signals. The analog sounds produced by the car radio or the CD player enter the audio system as low level signals. These low level signals travel through the audio system to a pick-up or a transducer. The audio preamplifier receives the electrical signal from the pick-up or the transducer and converts the low level signal into a line level signal.

What is a line level signal? A line level signal is an electrical signal with a particular audio strength. A line level signal has the strength that is required in a car audio system, a strength needed for the transmission of analog sound information.

The audio preamplifier does not alter the power of the signal in the car audio system. The audio preamplifier provides the audio system with a way to gain voltage. After a signal passes through a preamplifier, and after that signal gains voltage, then it passes into a power amplifier. The power amplifier gives the signal more power; it raises the amount of current in the signal.

The audio preamplifier also plays a role in the equalization of the signal. The preamplifier allows the audio system to correct for distortions in the sounds that are fed into that system. The equalization performed by the audio preamplifier allows the audio system to bring the car owner a quality sound.