With the touch of modernization, technology is evolving at a much faster pace where many new inventions are crawling to the surface. Each device or technique you encounter set you in awe of surprise and amusement. Today, machines have taken up the world and are assisting the masses in their everyday chores.

When learning about the audio amplifier, you will find how each section of the device can help you make the most out of your devices whether the mellifluous flow of your lead guitar or the blasting speakers of your luxury car.

audio amplifier

The audio amplifier is of many kinds, and it can be difficult to choose one according to your requirements. Whether it is for your home theater system or your car, selecting an audio amplifier can leave you very confused.

In this article, you’ll get to know some of the prominent audio amplifiers along with their specifications. Moreover, in this article, you ’ll be introduced to DIY audio speakers so that you can create one which meets your needs. What is Audio Amplifier?

1、Audio Amplifier

1.1 What is audio amplifier?
The audio amplifier is the electronic amplifier that tends to enhance the strength of electronic signals passing through it. It reproduces low power signals to make them strong enough to drive loudspeakers. For instance, the device receives signals from an electric guitar pickup then reproduce a low-power signal to a level that it powers the earphones or speakers.
The audio signal adjust the tone, effectiveness of the pitch and effects of the signals. It enhances the performance of any electronic audio device. When plugged into a car or in a guitar, it helps in adjusting the sharpness and frequency of the audio.
In order words, if the amplifier receives a hundred microwatts, it will reproduce the signals delivering only ten microwatts of signals. Its manufacturing involves functions including frequency, distortion, noise, and gain.

Audio Amplifier

Image 1: Audio Amplifier

1.2 Professional Audio Amplifiers
With the advent of various technological devices, there arises a need to create different amplifier suiting to the unique needs of every technology. In the audio market, some types surfaced over the years that assisted users in boosting the effectiveness of their devices by adjusting signals in the best possible manner.
Classified into different categories, the types of amplifiers offers different functionality and possess various features as per their classes. Learn about the most common seven classes:
Class A Amplifier- It is one of the simplest amplifiers of all with output transistors to conduct. It offers comparative lower efficiency output signals.
Class B Amplifier- There is a push and pull topology involved in Class B Amplifier where the outputs have two terminals a negative and a positive one. It’s a bit more efficient as compared to the Class A as it replicates the input signals only during the half cycle that is at 180°.
Class AB Amplifiers- It is a blend of A and Ab amplifier. It delivers the best functionality traits from each of the two individual categories, which is the efficient sound quality of Class A and the level of efficiency from Class B.
The two popular versions of Class AB, the MAX98309 and MAX98310 are used in digital cameras, media players, e-readers, and tablets in which a high fidelity is required.
Class D Amplifier- It is the highly efficient version of audio amplifiers, which reduces power consumption. It keeps the device working for longer eliminating the need to recharge the batteries. In its functionality, the output transistors are turned off during the operation, thus eliminating the need to use linear regions present on the transistors, which contributes to the inefficiency of the amplifier.
Class G Amplifiers- It is a more advanced and efficient version of Class AB Amplifiers. The Class G amplifiers require two or more supply voltages. When it operates at a low signal level it automatically, select the appropriate level of supply voltage.
Class DG Amplifiers- Much like Class D amplifier, the DG amplifier uses pulse-width modulation for producing digital output signals having variable duty cycles. It shows a bit of advanced functionality by using a multilevel output stage that assists in sensing the magnitude of output signals.
Class H Amplifiers- Similar to Class G amplifier it uses the technique to reduce dissipation around the output devices. The topology of Class H minimizes the voltage by modulating their supply voltage across the outputs.

Audio-Amplifiers

Image 2: Audio-Amplifiers

2、An Early History of Mini Audio Power Amplifiers

In 1906, the first audio amplifier was manufactured which consisted of a tube-like mechanism. Lee De Forest created it in the form of a triode vacuum tube. It involves significant black infrastructure having huge output tubes, which used to release much heat.

In the 1970s, the silicon transistors replaced this technology, in which these little transistors use to reproduce the sound by changing the voltage using semiconductors. As the time passes, solid states transistors came into being. It is commonly known that many of the present amplifiers are in some way a form of solid-state transistors. A bipolar junction transistor is a perfect illustration of Solid State amplifiers.

With the technological evolution, in 1872, Matti Otala came up with the reason for the dissertations produced in the former versions of the amplifier, and he manufactured a modern face of mini power amplifiers. Some of the famous mini audio amplifiers include the following:

audio

2.1 Quantum Audio Amplifiers
As per physics, the functionality of quantum amplifier is based on that of quantum mechanics. The device uses quantum mechanical techniques and phenomena to amplify the quantum signal.
In other words, an amplifier increases the amplitude of the signal that passes through it; however, the quantum amplifier takes in the signals present in the coherent state. At the output, the amplifier intensifies the input. Moreover, it can also amplify the quantum noise, which is present in the signal.

Audio Amplifiers

Quantum Audio Amplifiers

2.2 VM Audio Amplifier
A VM amplifier is the first asset of a professional guitarist. It adjusts and moderates the pitch, distortion, and frequency of the sound. The devices reproduce the digital signals and offer functionality including reverb, depth, gain, drive switch, cover, mix and effect adjustments.

Audio-Amplifiers3

VM Audio Amplifier

3、DIY Audio Amplifiers

Making a first audio amplifier, mainly based on the LM386 is quite simple. The hardware components used to make this simple amplifier include:

Texas Instruments LM386
9V battery
Resistor 10k Ohm
Capacitor 220 µF

The LM386 is a low-voltage audio power amplifier suitable for battery-powered devices like hobby electronics project, guitar amplifiers, and radios. Moreover, the IC consists of an 8-pin dual in-line package which is capable of offering an output of 0.25 watt to 1 watt of power with a 9-volt power supply depending on the model.
Components used

Apart from the components listed above, you’ll also need:
A Speaker
An Audio jack
Connections

While this might seem a little troubling, connections are pretty easy
The 9V ground negative will connect at pin 2 and pin 4.
The 9V battery positive terminal to be connected to pin 6
The positive terminal of the capacitor will be attached at pin 5
The other pins will have no connections

Other connections you’ll have to make include:
Negative terminals of the speaker connected to the speaker
The other end of the resistor connected to the Audio IN

After making the connections, you need to solder the components together. Make sure you use a PCB (printed circuit board) instead of point-to-point soldering as utilizing a PCB is much easier. Finally, check the connections and test out your amplifier!

4、Car Audio Amplifiers

Amplifiers are the first element that fine-tunes your car sounds. You may not be able to see the parts of the amplifier, but it is buried inside the car. It helps you enjoy the fun of loud music and to indulge in the rhythm of the music. If you do not install an amplifier, you will never be able to experience the quality of music.

4.1 Specification and Functionality of Amplifiers

•Preamplifiers of the Car Audio System
The functionality of the amplifier slightly differs in the car audio system where more than one pre-amplifiers are used to price the signals. The amplifier boosts the signals to let them move the speaker cones for creating a sound. However, before simplifying the sound, the signals are processed using the “pre-amp.”

In the car system, the pre-amp has to collect the many different signals from the various car heads including CD ROM, and radio to output them to the amplifier.

In short, it helps the amplifier to adjust the base, do the equalization and fine-tune the sound.

•Crossing Over
In the stage of passing over, the preamp performs a processing in which it divides the full range of audio signals into separate frequencies. It regulates signals to the different categories of speakers like woofers and tweeters.

•Power and Heat
During the preamp processing, the amplifier releases a massive amount of heat that alters the electric current working in the conjunction to create sound. In an automotive environment, tube amps are not recommended to use since they generate heat and vibrations.

Therefore, as an alternative electronic transistor amplify the audio signal. The amplifier boosts the line-level signal using the electronic components such as resistors and capacitors. The amplifiers do generate heat during this process. But they are manufactured in such a manner that they do not experience overheating.

5、BJT Amplifier Circuit

5.1 What is a BJT Amplifier?
Bipolar junction transistor (BJT) includes two semiconductors material forming a PN-junction. It is created by joining the two conductors back to back. You get two terminals namely P and N. Upon combining the two terminals; And you get a three-layered transistor having two junctions. It forms the basis of a Bipolar Junction Transistor.

5.2 The Functionality of Bipolar Transistors
Wile,a standard transistor is a three-layered or commonly called as a three-terminal device, which is manufactured using different semiconductors. It offers functionality as an insulator and as a conductor. This ability of transistors makes them perform essential tow function, which includes switching and amplifying.

Three different regions are involved in bipolar transistors namely:
•Active Region
•Saturation
•Cut-off

5.3 Bipolar Transistor Configurations
In the bipolar transistors, three most essential terminals are included which are called the Emitter, Base, and Collector. Having three terminals opens three ways to connect each of the two to form a transistor the common combinations are listed below:

Common Emitter Configuration.
I this arrangement the transistor can deliver a medium input to medium output impedance. It provides a high voltage and current gain.

Common Emitter Configuration

Common Emitter Configuration

Common Base Configuration
This arrangement is used commonly for making RF applications where the terminals deliver a low input to a high output impedance. Usually, the current receive is low while the voltage gain is higher than it.

Common Base Configuration

Common Base Configuration

Common Collector Configuration
Commonly called the Emitter follower, this configuration provides a high input to a low output impedance. Here the voltage gain is much lower than the current.

Common Collector Configuration

Common Collector Configuration

6、How to Choose the Right Custom Amplifier

Do the many technical features of an amplifier befog you when choosing the one you want?

Do you the things you should look for in an amplifier before you hand over the cash?

The guide below summaries the key points, which you must focus on when choosing an amplifier. The guide will walk you through the in-depth features and aspects to ponder on when laying your hands on any amplifier.

•Amplifier Channels
The foremost thing to look for is the amplifier channels. You have to choose the amplifier based on your need to have the number of output channels you want. You have to look for that particular type of amplifier, which is according to your needs. Many amps are there having two-four or mono sub-ports. By having an amp with many ports, you can experience the versatility and can power hue devices as well.

•Power of Amplifier

Secondly, you need to focus on the power of your amp. Two kinds of power ratings are there which are as follow:
•Peak Power
The peak power is that kind of power, which the amplifier produces for a limited burst. It is not that useful and is seen as the numbers that appear on the amp.

•RMS Ratings
It is the continuous calculation of amp’s power output. You must check the RMS numbers when finalizing the amplifier.

Audio-Amplifier

To know which rating is perfect for your speakers you can do one thing. Choose the amp, which has higher scores than that of your speakers because the more power your amp possess, the better, will be the sound of your music. If your speakers show 200-watt RMS, then it is best to go for 250-watt ratings of the amplifier.

•Amplifier Features
Apart from the ranks and sub-ports of your amplifier; you must take a look at its features. Then the most recommended features that your amplifier must have included:
High/low- pass filters
Speaker level inputs
Bass boost

•Amplifier Build Quality
Do you wonder why you should look for a high-quality amp?

In a custom board amplifier, which may be of a higher, price but depicts the most excellent quality makes you able to experience music with the most excellent condition. So you get the ports to plug in every primary cable, all at the same time.

You can have a much larger beefier component with a vented heat sink to keep the amp cool and to protect it from over-heating. Therefore, in this way, a high-quality amp offers the highest quality performance with better sound.

•Amp Wiring
The last and the most important section is the amp wiring. Its wiring can predict the overall performance of your amplifier. Invest money in purchasing a high-quality wiring kit to make sure that the wires supply power to the ends of the amplifier.

You can seek assistance from the professionals who can guide you in choosing the right amp wiring and a combination of features according to your needs. As a wrong combination of wiring and amps features can cost you a lot, so it’s always better to stay close to a professional and ask them to guide you about choosing the amplifier that can deliver the best performance and does not cost so more.

7、Conclusion

As a technology geek and as a music fan, you’d want an amplifier ideal for you! To get help with your audio amplifier or to pick an audio amplifier that meets your needs, contact Our PCB today! We will be glad to cater to all the problems you are having with your audio amplifier!