THE IMPLEMENTATION OF 120WATT AUDIO AMPLIFIER SYSTEMS

CHAPTER ONE

1.0       INTRODUCTION

An audio amplifier is an electronic device that amplifies low-power audio signals to a level suitable for driving loudspeakers and is the final stage in a typical audio playback chain. The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification, equalization tone control, mixing effects, or audio sources. Most audio amplifiers require these low-level inputs to adhere to line levels.

In simple terms, an amplifier speed up weak signal. It is wide in several devices to boost electrical signals . It can be used to play music from an ipad, ipod, tablet or android phone. The input of the amplifier is connected to the output of the USB port audio cord or memory card adapter, while connecting device (e.g. phone) connects to the amplifier through USB port audio cord.

There are other applications of amplifier and it is not easy to enumerate them all. Some of the common types of amplifiers are used in electronic gadgets and audio systems. These are also used in musical instruments e.g. guitars. Apart from the above, many other types of amplifiers like vacuum tube or value, transistor, operational and fully differential amplifiers are also used for specific purposes.

1.1       BACKGROUND OF THE STUDY

For many years now following the introduction of solid state amplifiers, their perceived sound did not have the excellent audio quality of the best value amplifiers. This led to audiophiles to believe that valve sound had an intrinsic quality due to the vacuum stop tube technology itself. In 1972, Mattie Otalei demonstrated the origin of a previously un-observed form of distortion: transient intermediation distortion (TIME), also called slow rate distortion. TIM distortion was found to occur during rapid increase in amplifier output voltages TIM did not appear at steady state sine tone measurements, helping to hide it from design engineers prior to 1972 problems with TIM distortion stem from reduced open loop frequency response of solid state amplifiers. Further works of Otalei and the authors found the solution for TIM distortion, including increasing slow rate, decreasing preamp frequency bandwidth, and the insertion of a lag compensation circuit in the input stage of the amplifier. In high quality modern amplifiers the open loop response is at least 20kHz. Cancelling TIM distortion. However, TIM distortion is still present in most low price home quality amplifiers.

The next step in advanced design was the Baxudull theorem, created by Peter Baxaudall in England. This thereon introduced the concept of comparing the ration between the input distortion and the output distortion of an audio amplifier. This new idea helped audio design engineers to better evaluate the distortion processes within an audio amplifier. Today, due to the existing applications of amplifiers, some of the common types of amplifiers are used in electronic gadget and audio systems. They are also used in musical instruments. Apart form the above, other types of amplifiers like vacuum tube or valve, transistor, operational and fully differential amplifiers are also used for specific purposes. Video amplifiers are of diverse kinds. The high power audio amplifier that is implemented in this project is a type of amplifier that supplies high power audio output that are required for use in churches and public place.

1.2       AIM OF STUDY

The aim of the study is to achieve the use of 120W home theater amplifier with USB ports which can also be used in Audio cord, microphone jack and musical instruments and widely several devices to boost electrical audio signals.  

1.3       OBJECTIVE OF THE STUDY

The objectives of this study is aimed at providing a means of amplifying a low level audio signal to a high to a high level audio signal and also greatly improving the audio quality. 

i.                    To boost electrical signals

ii.                  To be used in radio television and telephone.

iii.                 To be used in amplifiers

1.4       SIGNIFICANCE OF THE STUDY          

Ever since stereophonic sound become popular in 1950’s the race has been on to create the ultimate home listening experience.

This project not only amplifiers the sound, but it also give a good sound background and create a good listening experience.

The power of amplifier seems to have become the glamour component in music system, examples to point out in this regard. There are innumerable others of an audio amplifier. This new idea helped audio to better evaluate the distortion processes within an audio amplifier.

Important applications of the audio amplifier include public address systems, theatrical and concert sound reinforcement, and domestic sound systems.

This project present the guiding principles for the implementation of 120Watt audio amplifier system.

1.5       SCOPE AND LIMITATIONS

The home theater amplifier with USB port that is designed in this project provides audio amplification of 120w power output. The amplifier focuses its outputs on the range 1- 30m supply output within these range of coverage . The home theater with USB port amplifier audio cord, card reader, microphone jack plug and in-built speaker find its applications in some places like conference halls, theatre halls and homes. Despite the numerous advantages and applications offered by the project. It is also limit by some factors namely:

1. The project is relatively expensive to implement due to the high power requirements.
2. The USB port amplifier  range is not more than 20 m for good signal output.
3.   Durability of USB port amplifier.