Of all the amplifier classes, only four are commonly used in car audio systems, and one of them is a combination type. These four amplifier classes are A, B, AB, and D. Here is a brief introduction to these amplifier classes.
What is the difference between amplifier classes? | Crutchfield
At a basic level, there are only two types of power amplifiers: analog and switching. These basic types are further divided into more than a dozen lettered classes. Some of these, such as T and Z, are patented, trademarked designs, and others, such as A and B, are produced by several manufacturers.
All power amplifiers perform essentially the same function and operate on the same basic principles, but not all amplifiers are created equal.
By definition, Class A amplifiers are always on. They use internal circuitry that is designed to always have current flowing through the output transistors. This basic design has advantages and disadvantages that make Class A amplifiers good for some applications and bad for others. The biggest problem when it comes to Class A amplifiers in car audio applications is size.
