Audio - A Brief Guide To Understanding Audio Amplifier

The simple aim of an audio amplifier is to convert a low-power audio signals to a high-power audio signals. High power signal is big enough to drive a speaker is quite loud. To do that amp uses one or more elements that are controlled by a low power signal to generate the electrical signal. These elements range from tubes to transistors FEET bipolar transistors.
Amplifier tubes used for public several decades ago. A tube to control the flow of current in accordance with a control voltage that is connected to the tube. Unfortunately amplifier tubes have a high enough amount of distortion. Technically tube amplifier will introduce higher harmonics into the signal. However, the characteristics of tube amps still made it popular. Many people describe tube amps have a warmer sound than solid state amps sound cold.
Another drawback of tube amps though is the low power efficiency. The majority of the consuming power tube amps being dissipated as heat, and only a small portion is converted into audio power. Also the tube is quite expensive to make. So tube amps have largely been replaced by solid-state amp that I will see next.
Solid state amp to replace tubes with semiconductor elements are usually bipolar transistor or FEET. Types of early solid-state amp is known as a class-A amp. In class-A amp transistor controls the flow of current in accordance with the small signal levels. Some amps use feedback mechanisms in order to minimize harmonic distortion. Class-A amp has the lowest distortion and noise usually the lowest amount of any amplifier architecture. If you need an ultra-low distortion then you have to take a closer look at the class-A models. The main drawback is that it is similar to a class A tube amp amps have very low efficiency. As a result, these amps require a large heat sink to dissipate the energy wasted and usually quite large.
Class-AB amp improve the efficiency of a class-A amp. They use a series of transistors to break the signal level into two separate areas each of which can be amplified more efficiently. Thus, class-AB amps are usually smaller than the class-A amp. However, this topology is to add some non-linearity or distortion in areas where signals move between regions. Thus, class-AB amps typically have higher distortion than class-A amp.
Class-D amps improve the efficiency of a class-AB amp even further by using a transistor switching constantly switched on or off. Thus the phase shift is almost gone any power and thus energy efficiency class-D amps are usually exceeded. Transistor switching is controlled by a pulse width modulator. Large signal level switch must be low pass filtered to remove and recover the signal switching audio signals. Due to non-linearities of the pulse width modulator and transistor switch own class-D amp by nature have among the highest of any audio distortion audio amplifier.