Amplifiers, or amps as they’re more popularly known, are indispensable parts of the sound industry. Concerts, clubs, and conferences would be incomplete without them. So, what exactly are these things, what do they do, and how do you use them?
This article aims to tackle exactly that. If you’re curious about these technological inventions that have forever changed the map of communication, this article will take you through all the aspects of amplifiers, their types, and how they’re used.
What is an Amplifier?
At the risk of oversimplifying it, an amplifier is a device that amplifies a signal. In this article, we will be talking about sound amplifiers, but let’s first talk about the general terms associated with it for a bit.
The word amplifier comes from the physics term amplitude. It is defined as the maximum extent of a vibration or oscillation, measured from the position of equilibrium. In layman’s terms, the bigger the amplitude, the more the intensity of the signal is. In this case, the bigger the amplitude, the louder the signal.
And this is exactly what an amplifier does. If a musician is playing his guitar on the stage and singing along with it, there is no way he can be heard past the first two or three rows. Amplifiers make it possible for the signals from his microphone and his electric guitar to be at a level that can be heard throughout the arena.
If you’re interested in knowing more about the physics aspect of amplifiers, check out this article on how amplifiers work.
We take things like our headphones and speakers (even the ones on our phone!) for granted, but most of these have built-in amplifiers that make it possible for them to produce sound. Sound from any source is read in the form of electric signals, and these signals are then transmitted via preamplifiers (or preamps).
What is a Pre-amp?
Ever wondered why your voice on audio recordings sounds so terrible? It’s because there’s no preamp on the mic when it comes to most recordings.
The difference between a preamplifier vs amplifier is that the former picks up signals of much lower intensity. In the sound industry, the level of these low-intensity signals is called the mic-level. Preamplifiers make sure that the mic-level or instrument-level signal is picked up and amplified properly.
When we say properly, we mean that not all signals have to be amplified. The reason voice recordings sound bad is that there is too much background noise in them. The human ear has adjusted itself to ignore the sounds around us due to their perpetual nature, but machines are unbiased, and they pick up on everything.
Therefore, a preamplifier does an important job. It amplifies the relevant noise and sends it to the main amplifier (also called the power amplifier), letting it do its own job of making these important signals even louder for the loudspeaker.
This technology, however, has been modified and improved to ensure that you do not need two separate instruments to get this done. This is where integrated amplifiers come into the picture.
What is an Integrated Amplifier?
When you listen to music on your phone speakers, you are not getting the real experience of what the artists intended it to sound like. This is because the artists used top quality instruments in professional studios while recording their music, while your phone speakers do not have the required hardware to accurately recreate it.
Integrated amplifiers are your workaround for this problem. If you’re looking for high quality, smooth, and background noise-free sounds, you need both an amplifier and a preamplifier in your setup.
An integrated amplifier puts together (or integrates) the preamp and the power amp in a single instrument. This not only helps you save infrastructure and space, but also gives you excellent audio quality.
There are several other engineering and audio advantages to integrated amplifiers. When you have all your amplifying functions in a single setup, you are essentially isolating the source signals from the integrated amplifier.
When it comes to audio advantages, the engineering advantages themselves help in cleaner sound quality. But besides this, the source signals might be of different kinds of sources, and when they interfere with each other, it reduces the quality of the audio. The source signals generated with an integrated amplifier do not interact or interfere with one another by design, giving you audio that is low in distortion.
Stability is an important part of sound systems. Several high-quality sound systems rely on inverting their outputs by a phase to improve this aspect, and this brings us to a different type of amplifier: Inverting Amplifiers.
What are Inverting Amplifiers?
This is where things get a little technical. Now as you probably know, sound travels in waves. And each of these waves has a particular phase.
The difference between an inverting amplifier vs non inverting amplifier is in the output that both these types of amplifiers produce. While non inverting amplifiers have an output which is in the same phase as their input, inverting amplifiers switch the output by 180 degrees out of phase with the input signal.
This does not make a difference when there is just one output channel. For example, if you’re listening to mono audio, the difference between the sound outputs from an inverting amplifier vs non inverting amplifier will be negligible. The main difference is when there are multiple output channels.
For example, if you’re listening to stereo speakers, you will have two output channels. For this, you will need a non inverting amplifier for the best quality audio. Delay or inversion of the signal does not matter when you’re listening to a single channel.
The reason why inverting amplifiers are used is that the relative inversion between channels matters. If there is not a proper phase relationship between the channels, the perceived sound position from the source won’t be correct, and you will hear a distorted version of the sound you were originally meant to hear.
Look at this way. Let’s say there’s a recorded audio and instrumental part each to a song. This would be completely fine on a non inverting channel. But as you know, songs are not recorded this way, and there are multiple layers of vocals and instrumentals that are put on over the original beat.
Now, if you add more vocals to the previous mix on the same channel, the original vocals would disappear, because the new vocals are not being added to the song, but are replacing them. Therefore, to make a proper soundtrack (or other similar processes in the sound industry), you need an inverting amplifier.
Classes of Amplifiers
If you look at the specifications of any amplifier, you will notice that every amplifier comes with a class of its own. These classes are a depiction of how these amplifiers function at a core level. The most common amplifier classes that you can see are A, AB, D, G, and H.
Class A amplifiers are one of the more simple devices you will come across, and they function on the principle that all of the amplifier’s output devices must be conducting through the full 360 degrees of a waveform.
Class B amplifiers differ from Class A amplifiers in the sense that only half of their output decides are conducting at a given time, and each half covers 180 degrees of the waveform. This increases the efficiency of a Class B amplifier.
Class AB amplifiers put together the best features of Class A and Class B amplifiers, making a system that varies from 181 to 200 degrees, ensuring that distortion caused by crossover is avoided.
Class G and H amplifiers are just different types of AB amplifiers. Class G amplifiers use voltage rail switching to give a better output, while Class H amplifiers use rail modulation. Due to this reason, both these types of amplifiers consume lower power than a typical Class AB amplifier.
If you’re interested in knowing about this topic in a more detailed way, you can check out this article about the different classes of amplifiers.
Now that we’ve gotten all that bookish knowledge about amplifiers, their types, and what they’re used for, it’s time to get to the more practical aspects of them. In the following sections, we get into how to install an amplifier.
The amplifiers that we use in our day to day life are transistor-based. These are used to amplify signals on your TV or radio, voice over phone calls, or input from microphones or hearing aids.
Now there’s always a limit to how much output you can get from an amplifier. If you want to record something in a studio or use a hearing aid, you’ll need a much smaller amplifier than you will need for a loudspeaker in a stadium.
Another factor that controls how much the output is amplified is in the form of multistage amplifiers. This basically means that you connect more than one amplifier to the input. This does NOT equate a multiple speaker system. When it comes to multistage amplifiers, the concept is that the amplified output from one amplifier goes to the input of the next amplifier.
Let’s try to explain this with a very basic, oversimplified example. Let’s say that your input wave has the intensity of x. You need an output of 16x, and each amplifier you have amplifies it by a factor of 2.
Source (x) – Amplifier A (2x) – Amplifier B (4x) – Amplifier C (8x) – Amplifier D (16x)
The actual process is a lot more complicated, but this is the general concept of how multistage amplifiers work. Let’s delve into more practical applications of how to use your amplifiers with other sound equipment for high quality, low distortion noise output.
How to Connect your Speakers to an Amplifier
Connecting your amplifier with your speakers can seem like a daunting task because of the steps involved in it, but it is a simple procedure if you know what you’re doing. Below, we take you through all the steps that you need to figure out how exactly to get your sound system working.
If you do not have spade connectors or banana clips at the end of your cable, these steps will guide you on how to use your cables without those connectors, or how to put on those clips at the end of them if you have access to them.
- Cut a length of dual connector cable by using a set of pliers, enough for the distance between your speaker setup and your amplifier.
- Using pliers, make a small cut on the beginning of the length of your cable, and use it to separate the two wires for about two inches.
- Now you will need to strip both these cable ends for about an inch from the end so that you can see the naked wire under it. If the wire has a plastic casing under the insulating material, make sure you remove that as well.
- Twist both ends of the exposed wire. One of these is the positive terminal, and one of them is the negative terminal. You can choose whichever side you want, but remember your choices.
- Unscrew the binding posts on the back of your speaker, connect these wires and screw the tops back on. If you have a spring type, just press the button, put the wire in, and let go of the button.
- With banana clips, make sure you fan the wires after you insert them and screw the top back on. The process is much easier with banana clips because you can just plug them in, without having to screw it in every time.
Always, always make sure that the positive and negative terminals are matched correctly on the speakers and the amplifier input ports. This shouldn’t be difficult, as most decent amplifier and speaker systems come with color-coded ports on the back. These are mostly black and red but might come in other colors as well.
If you’re more of a visual learner, you can check out all these steps mentioned above and how to do it right by watching this video on connecting amplifiers to speakers.
How to Connect a Mixer to an Amplifier
If you’re in the music and sound industry, just knowing how to connect your amplifier to your speakers is not going to suffice. You will need to know how to connect a mixer to an amplifier as well. Before we get into the steps on how to connect these, let’s talk about what a sound mixer is.
A sound mixer (sometimes also called an audio mixer or a mixing console) is a key component in most major concerts and live events. DJs would be lost without this piece of equipment. A mixer does what its name suggests – it mixes sounds.
A mixer takes multiple audio signals, merges them together to the same levels of amplitude, and gives out one or more output signals. When DJs merge their beats flawlessly from one song to another, they’re using audio mixers. When the “beat drops,” you are basically hearing another audio signal, the one with the beat, being added to the ongoing soundtrack.
Soundtracks and beats can be optimized and filtered by enhancing sounds with effects and equalizations, adjusting their levels, and creating monitor feeds by mixing and matching the different audio input options available.
If you’ve ever seen a hip hop music video that features a recording studio (think Dr. Dre and Eminem), you will see sliders on the huge mixers present there. These sliders are called faders, and they allow you to control the volume of each individual channel. Essentially, you can control the recording of the vocals, the beat, and the instrumental separately with the help of faders.
There are a lot of different options on a mixer that helps musicians, producers, and DJs make the music that you listen to. If you’re interested in knowing more about mixers, check out this article that talks about the working of a mixer.
Now that we know what mixers are and what they do, let’s get into how to connect a mixer to an amplifier.
- If you look at the back terminal of the mixer, you will see a lot of different input options. The one that says Phono is meant for normal turntables that use vinyl. Vinyl turntables are only used by very few DJs nowadays, as most records are stored and mastered digitally.
- The Line option is for your CD turntables. Again, this is a port used by DJs for their CD drives.
- You will see a lot of Line and Phono options in the back of the mixer, which is meant specifically for DJing and similar purposes.
- There is an option called Grand on the mixer. Again, this is meant for old school vinyl turntables, and won’t be of any use to you if you’re working with digital records.
Connecting your speakers to the mixer is easy, and the same as the previous method mentioned. You will need a dual cable with stripped wires, or you could work with spade hooks or banana clips to make plugging and unplugging your speaker setup from the mixer easier.
- Use the negative terminal to plug into the Com, and the positive one into the 4 ohms (or similar) input option.
- Now, your mixer needs to provide input to the amplifier. Therefore, you need to connect your cable to the Output channel on the back panel.
- You will see an input option called Output on the mixer’s back panel. If you have a single cable setup, use the Left option on the Output ports on the mixer, and then connect it to the Aux port on the amplifier.
- If you’re connecting more than one mixer to your amplifier, make sure that you select the Right option on that Output port.
- Most amplifiers have multiple Aux options, so you can easily provide it with more than one input. In this case, the input would be the signal from your mixer.
Mixers can have a lot of input and output options, making their back panels very complicated. Once you know which port means what, it should be easy for you to figure out where to connect the amplifier and the speakers. If you’re interested in more of these methods, take a look at this video on how to connect equipment to a mixer.
Amplifiers are a necessity in today’s world, not only in the sound industry but also in day to day life. Your radio, your TV, and even your phones have certain types of amplifiers, and these instruments help make your life easier. For people with hearing problems, amplifiers in their hearing aids give them the gift of hearing.
Your favorite artist would not have been able to perform in front of thousands of people without an amplifier. Your neighboring club would not be able to have its regular DJ nights and live music events without amplifiers. As you can see, amplifiers are present in all walks of life and technology and make your life much easier with their design!
We hope that this article has helped you understand the working of an amplifier, the places and situations where they are used, their classes, and the correct procedure on how to install, connect, and use them.
If you are someone who works in the sound industry or even just an independent artist who is looking for equipment, be sure to check out our buyer’s guide for the best amplifiers on the market as well!