How do Audio Amplifiers Work?

More important (for me at least) what is an audio amplifier? Well, first of all it was invented by a man named Lee De Forest, in 1909,  by somewhat of a mistake because initially he invented a device called the triode vacuum tube (more on this in a later post), which was used to play the very first AM radio! How cool is that? It later resulted in the first audio amplifier! So , basically the audio amplifier is actually an electronic amplifier that in some way exacerbates low power audio signals that are usually in between 20 and 20000 Hz (the human frequency range of hearing). Some of the first audio amplifiers were based on vacuum tubes or valves.

Today, they use transistors (BJT, FET and MOSFET), but there are also a few enthusiasts that prefer to use tube-based amplifiers and valves, click here for more audio amplifiers circuits. There are a few important design parameters when it comes to audio amplifiers such as gain , distortion, noise and frequency response. These work independently and often the increase in one disrupts the other ones, so a perfect balance must be reached accordingly to one’s uses with the amplifier. Most of them are linear and part of class AB. Since the digital era, the DVD’s for example, almost all amplifiers are designed to use flat linear signals so usually for these kind of device a selector or a volume button may suffice.

The true purpose of the powerful modern audio amplifier comes in handy when you’re thinking large halls for public speakers and gatherings, stadiums, concerts, cinema halls, theatres, home cinemas and instrument amplifiers such as for guitars! The best contribution by far, in my opinion , in the developing of the state of the art, modern amplifier was that of Peter Baxandall who thought of the comparison of the input distortion with the output distortion. This helped engineers allot in evaluating the distortion process within an amplifier, thus resulting in the better sound quality we get today!