What Does a Car Amp Do?

A car amplifier can help boost the overall quality of the sound system. How exactly does it manage to do this and what does an amp do in a car that makes the sound more powerful?

To give you a better understanding of car amplifiers, we will take you through the following sections where you can not only learn about the uses and benefits of a car amp but can also figure out how it works.

Let’s get started!

What Is a Car Amp?

A car amplifier is a component of the sound system of a car that can either come built into it or can be installed separately to boost the sound.

Usually, the built-in amplifiers that are connected to the car’s stereo or head unit serve the purpose of driving up the sound.

However, these built-in amplifiers also tend to work on extremely low levels of power, causing them to work only up to a certain extent. At higher levels of outputs, these amps do not work too efficiently.

On the other hand, separate car amplifiers that you can install to the car stereo can work reliably for varying levels of outputs while also being able to provide better clarity and quality.

If you have limited needs when it comes to your car stereo, then the built-in system should work for you. However, for frequent travels, better efficiency and durability, getting an external car amp can make all the difference.

What Does a Car Amp Do?

You now know what a car amp is, but what does an amplifier do? Essentially, a car amp takes the audio signal that it receives from the head unit and makes it clearer and more powerful so that you can actually hear the sound better.

You can thus increase the volume to your desired levels to play your music at a loud enough volume without experiencing any kind of warps in the sound quality.

Of course, this works much better in an external amplifier since it is designed to withstand and produce greater power and output.

Apart from simply amplifying the sound, however, a car amp can also help power up the external speakers and subwoofers that you might want to install to the sound system to improve the quality even more.

Since the speakers and subwoofer require higher power to function efficiently, an external amp can work better as compared to a built-in amp.

In order to understand how much output a car amp can produce without any kind of distortion, a rating unit called the root mean square (RMS) is used to convey the watts produced by each channel.

A higher RMS will result in louder and more powerful output but your focus should be to ensure that the RMS is compatible with the capacity of the speakers.

How Does a Car Amplifier Work?

It is important to be aware of the functioning of car amps to get a better understanding of how they can make your car’s sound system better. How do car amps work, then? Let’s find out below.

Power Supply

The car amp receives around 12 volts of power which it then amplifies into a more powerful voltage that it can supply to the speakers. It does this using a switched-mode power supply which makes use of transistors and a transformer to increase the power.

It also keeps turning the input on and off using a wire.

It is important to ensure that you use accurate ratings when it comes to the cables.

Input Stages

There are several input stages in the amp that perform a range of functions that you can look into below.


The inputs are essential to connect the amplifier to the stereo of the car without making use of the RCA cables or connectors. They can then help make the connection using the connectors.

Preventing Noise

A circuit in the input stages is also responsible for minimizing the noise level whenever the audio signal is supplied to the amp. This kind of noise is generally a result of the changing speed levels in your car that can result in a whining or looping sound that can distort the sound quality.


Crossovers are frequency settings that generally get sent to the speakers that can then help power the subwoofer in the sound system. It is important to regulate this crossover frequency so that the sound that is ultimately amplified and boosted does not end up sounding warped.

This can then prevent damage to your speakers while also improving the volume.


Gains in the amplifier can help determine the power output of the amp based on the signal conversions that take place inside it. By regulating these gains, the input stages can help ensure that the final sound is clearer and more compatible with the other components and processes of the amp, including the outputs.


To produce the output, the amp first passes the signal through transistors that produce negative and positive branches of the current which then pass through some more transistors that increase the power levels of the signal. This output can then send powerful signals to the speakers.


There are several kinds of amps depending on the number of channels that they have. These channels determine the track followed by the audio signal so that they can then lead to the output.

Car stereos usually provide left and right channels while some may also use front and rear ones on top of the others.

Commonly, car amps tend to come with two or four channels that you can pick from depending on the requirements of your sound system. Usually, you should aim to match at least a single channel to a single speaker for the best possible results.

It is also possible to bridge the channels to produce more output.

Connections and Inputs

There are several connections and inputs involved in a car amp that you should know about to make the installation process easier. Let’s take a look at these below.

Power Connections

You should use large-gauge copper wires for making the power connections. You can easily find these from local stores or simply from the wiring tools that come with your amplifier.

Speaker Connections

Speaker connections generally use RCA connectors for connecting the car amplifier to the head unit as well as to the speaker. Make sure you do not end up placing the speaker and power connections on the same side.

Non-RCA Connections

Non-RCA connections are those that use speaker-level inputs to convert the required signals into a compatible enough voltage level.


Make sure you use the necessary wiring tools to install the car amp so that you can ensure that there are no distortions or accidents. It is important to keep the wires compatible enough with all the components of the sound system, especially since the cables present in the stereo are quite weak on their own.

You will need to connect all the relevant wires such as power cables, ground wires, remote wires, RCA cables and speaker wires.

Choosing a Car Amp

It is important to be aware of your own sound requirements when it comes to choosing a car amp. More importantly, however, you will need to ensure that all the components of the sound system are compatible enough with the amp, such as the head unit, speakers and the subwoofer.

Make sure you choose a car amp based on the number of speakers that you have and where they are situated. You should also look into the kind of speakers that you have and how much power they need to work efficiently.

The cost can also add to your decision.


What Is the Difference Between 2-Channel and 4-Channel Amps?

A 2-channel amp can provide sound control and regulation for the left and right speakers, serving all your essential needs. A 4-channel amp can not only serve left and right speakers but also front and rear ones. You can also bridge channels in the latter.

Do Car Amplifiers Make a Difference?

Car amplifiers can make a big difference to the sound quality and volume. It can get rid of warped sounds as long as there is compatibility with the other components.

It can also power the speakers and subwoofer while also allowing you to control the audio of your car stereo system.

Do I Need an Amp for Speakers?

It is possible to connect speakers to the head unit’s built-in amp, but this will not be enough to power the speakers properly, which is why it might be better to buy an external amp.

This can also help remove sound distortions and prevent any damage to the speakers, ensuring durability.

Concluding Remarks

You have now seen all the uses and benefits of having a car amp. To sum up, a car amp can use the audio signals of your car stereo and turn them into more powerful outputs for your speakers to produce a better sound.

This involves several processes, connections and components that we have also delved into. Go ahead and improve the sound quality of your car stereo!

Last Updated on November 7, 2023 by Brian Beasley

Written by Danny Reid

Hey, I'm Danny, and I know how hard it can be to find the perfect audio gear. Need a new stereo, amp, speakers, or subs? Don't worry – my blog is here to help you cut through the noise! My mission is to give you the best reviews, so you can make the right decision for your audio needs. And if you ever get stuck thinking, "Where does this blue wire go?" don't worry – I've got tons of cool tips to help you out of any jam. So come along with me on this fun, sound-filled adventure, and let's find the perfect audio setup to make your tunes really sing!