How to Connect Your Amplifier To A Car Stereo?

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Music is the key to the hearts of most people. It’s virtually a source of relief from pressure to a lot of people.

There are people who can’t just do without music wherever they go; in the house, while they take a stroll, during exercises, during breaks at work or in their cars.

How to Connect Your Amplifier To A Car Stereo?
Photo Credit: Sindre Strøm, Pexels.com

If you fall into the category of people who love music for relaxation and you also want to get this soothing pleasure in the car but you are unable to, then you are certainly welcome to try out the steps outlined in this article.

This is a detailed explanation of how to get your car stereo system and amplifier to work and get them ready to bloom out with music anytime you go for a drive in your car.

If your car stereo produces tacky sounds or the audio quality isn’t good enough, then your sound system needs an amplifier.

An amplifier is an electronic device that increases the input signals it receives from the stereo and gives a stronger output signal to your speakers.

So if your system lacks an amplifier it is advised you purchase and install one for better performance. On the other hand, if you already have one and you lack the knowledge on how to get your car’s stereo work with it then feel free to join in.

Accessories and Kits Needed

You might not be well grounded in this area but you definitely need to get the necessary wiring equipment needed to get the job done. You might think that this will be difficult for you to comprehend and accomplish but surprisingly it is very easy.

As long as you follow these guidelines in purchasing the right materials needed to get your stereo system working. If you are lucky enough you may get the kits and wiring materials along with your amplifier when purchased but if otherwise, you will have to purchase them separately.

But first, make sure the car Stereo is installed in the space provided in the vehicle’s dashboard to start off, then get the following items which include

  • Inline fuse
  • RCA cables
  • Speaker wires
  • Ground wires
  • Connector plugs
  • Remote switch-on wire
  • Power cable

When purchasing any of the items above, ensure you get the types recommended by the manufacturer and adhere strictly to the ratings for each of the wiring kits mentioned above.

So to put things in perspective, we will discuss each wiring kit; its uses, location, how it should be used and type to be used. So, moving on to the next step we shall consider the following:

Inline fuse

When making electrical connections, it is important that there is a control measure in case there is a fire outbreak that can take you off guard. The inline fuse is designated for this purpose.

The fuse was introduced as a precautionary measure to protect wires and components from the extreme heat produced should there be an electrical overload or short circuit of appliances.

So, the inline fuse is placed on the power cable and should always be installed about fifteen meters away from the battery connection. This will ensure the safety of your car and the stereo from the inevitable fire outbreak which could be a result of a short circuit.

This also implies that you cannot just use any type of fuse for different sizes, width and length of wire. Now, this is where your manufacturer’s ratings come in handy. For any size and length, there is a manufacturer’s pick on the type of fuse you are supposed to use.

For the size of your vehicle, the length of wires to be used should be at the range of 16-20 foot and you can use the following fuse ratings for wire gauge such as:

*A 25-ampere fuse for a 10-gauge wire

*A 60-ampere fuse for a 8 gauge wire

* A 100-ampere fuse for an 8 gauge wire

*And a fuse rating of 250 amperes for 1- or 0-gauge wire.

RCA cables

The connections carrying input and output signals from the stereo and the amplifier are only done Via RCA cables. These cables are a certain type of wires which usually come in pairs. This type is important because essential electric signals travel through the stereo to the amplifier and vice-versa.

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Speaker Wires

When connecting to the speakers, it ought to be from the output of the amplifier which Is to be set up by it being connected to the stereo. The recommended thickness and size should be between 18 and 14 gauge which you can pick to suit your convenience and for the subwoofers if included.

You can use between the range of sixteen to twelve-gauge size for its wiring.

Ground Wires

Ground wires are used to earth electric circuits to channel and make waste of excess currents. This is done to avoid short-circuit, electric shocks and any other related calamities that may occur during electric fluctuations or lightening.

Wires meant for earthing ought to be thick in size to be able to accommodate the car stereo needs, using thinner wires could be hazardous to the user and thus could be putting his or her life at risk.

For the length of the wire, you can measure the distance to be covered in your vehicle using appropriate measuring tools. You can also refer to either the car stereo or amplifier manual to help you determine the best length and size to use during grounding and earthing connections.

Power Cable

Similar to the ground wires you have to use thicker wires in order to accommodate the current and voltage coming in. In this case, the power cable must be thicker in width because it is connected from the battery which generates electricity supplied to the amplifier and stereo.

In other words, a more standard cable should be used during power Connections unless you will end up either getting the connection short-circuited or starting a fire outbreak which is dangerous to you and your car.

Now that we have discussed the necessary information concerning the components used to start up the connection between your amplifier and your stereo, the next move is to select a location that will suit your amplifier, the speakers and wires respectively.

There is no need to worry about where to fix the stereo as most vehicles come with a pre-installed one or already has a location where one could be installed which is usually found around the car’s dashboard.

Considering where all these should be located, the size of your vehicle matters. A more familiar place where people install their sets are usually the car’s trunk but If you happen to drive an SUV then you might be limited in space.

Also, this concept is also important because you will know the right places to mount each component in order not to constitute interference or nuisance when your car stereo is switched on.

So here is a guide where you can considerably choose from to install such sets

Car Seats

You can make use of your car seats with an advantage of the connections requiring fewer wires and making the soundings of the car stereo system more efficient and noiseless.

There will be a reduction in interference levels between wires and also note that the car amplifier can fit in here with the speakers being placed at the top back seats or the front seats.

The only disadvantage to this choice is that only small-sized amps can fit through the spaces since it’s limited and also removing seats of the vehicle could disengage its airbag system.

Another constraint is the amplifier should be protected against water from accidental spills or from rain.

The Trunk

The trunk or the booth of your vehicle could be another good location to place and mount the amplifier with its sets and since the trunk provides more space you can mount very large amplifiers there.

The only disadvantage for this location is you will have to sacrifice the space meant for your luggage and other cargo loads when you have a lot on your hands to pack and transport.

Also, you will require longer wires for connections which will cost more even in the long run when they are due for changes and maintenances.

Firewall (Around the passenger’s seat)

This place is also up for consideration as you will have fewer wires to use and you won’t have to take off the seats of your car to fit in the amplifier and wiring set.

The problem you may likely encounter is that larger amplifiers may be unable to fit through such space and your stereo set will be prone to noise interference.

There might be other options you may already have in mind to fit in your amplifier and wiring kits. Before you proceed, make sure the size of your amplifier fits the space provided for it in the car.

If you can’t get all these factors confirmed then It is not advisable to install or mount your amplifier and wiring kits there.

Also, you should ensure where your amplifier is to be mounted should accommodate much ventilation because amplifiers produce a lot of heat and having it installed where it can get cooled easily is a smart move to avoid casualties and unforeseen circumstances.

After all the processes previously mentioned have been carried out, the next step is to figure out where you can fix all the wirings without it turning out unattractive.

Where you run the wires is important because it is very necessary that the wires do not interfere with anything else and should not obstruct your pathway while driving.

So, these are options you might consider for running your car stereo and amplifier wiring.

* Using the door scuff plate

* Through seat belts

* Running wires Behind the dash

Now, we can now go into the main deal and finally get the car stereo system installed. To be clear the major focus is the amplifier as the majority of the connection emanates from there and also the stereo can easily be fixed on the vehicle dashboard where its space is provided in most vehicles.

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Steps to Installation

Disconnecting the Battery Terminal

This is a precautionary measure taken when you are about to carry out the installation of a car stereo because you could get electrocuted when trying to get the connection fixed.

In order to avoid encounters like this, you must detach the negative terminal of your car’s battery and ensure your vehicle is switched off when carrying out all wiring procedures.

Install the amplifier

We discussed previously the appropriate locations you can choose from, and we recommended that you choose from those categories. When you have made up your mind on the choices, you can fit your amplifier according to the conditional needs.

You are advised to fasten your amplifier to this location with a screw to prevent it from falling out of place unexpectedly. You can make a hole that can fit through the amplifier to ensure that damages are not done to the vehicle bodywork.

You can also enable adequate fastening of screws through it. The amplifier should mount on its bottom surface and should not be placed in an inverted position to avoid heat circulating into the amplifier.

Connecting the Power Cable

When connecting the power cable find a grommet that can accommodate the size of wire to be used. The wire should be placed in your vehicle’s firewall where it would be connected from your car’s battery through to the amplifier.

But if you’re unable to get grommet you will have to drill your own hole in a way that penetrates the firewall and ensures the wire and any other components of the car don’t get damaged.

The essence of the grommet is to protect the power cable from wearing out and getting short-circuited. This part of the connection is important because the power cable is responsible for the powering of the stereo and the amplifier.

This is why it was stated earlier to make use of the thick wires as they consume more voltage and current as they supply to the load.

Installation of fuse

Most of the electrical devices come with installed fuse and circuit breaker devices in case of unforeseen electrical difficulties but with an exception of the power cable.

The power cable may be included with a fuse but if not, then cut the power cable at a particular junction. Keep at least 15 centimeters gap away from the terminal and get the fuse holder within that region so it can be taken care of there.

Making sure the power cable is connected properly

Ensure the power cable is connected and fixed to the positive terminal of your car battery. Make sure it is not connected directly to the battery but fixed on it with a power cable ring that comes with the cable.

Providing a wire loom for the power cable

To reduce the heat induced by the power cable mounted on the battery which is located near the vehicle’s engine, you will have to secure the wire with a loom that provides protection against heat.

If included among your kits, coat the wire from the battery position until it gets to the firewall and then cut it to fit size.

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Ground Wiring Connection

This is one of the most crucial connections because if this wiring connection is not done properly it could lead to problems in the future. So, you are to adhere strictly to this procedure and go over it to understand carefully where each connection should be placed.

As a house is usually earthed and grounded so should it be for your amplifier and car stereo system for its protection against any electrical casualty that may occur.

You should find a very close location to the amplifier, drill a hole to a diameter that can accommodate the size of a bolt and nut where eventually the ground wire would be fastened to.

Ensure there is no blockage or non-conductor present as a conducting metallic material is required for the grounding of these connections.

Video: How to connect the amplifier to car stereo

This video explains the procedure for installing car audio systems.

Installation of the remote turn-on wire. 

The turn-on cable enables the amplifier power when the vehicle engine is on and the stereo booted up. To carry out this connection, remove the stereo from its position usually from the dashboard.

When you have done this, the next step will be to locate the remote turn-on wire located at the back of the stereo which is usually a blue or white wire.

Locate the same wire on the amplifier which will be labeled as ‘turn on’ and then join both of them together.

Confirming the signal connections

This is where your RCA cables come to use. You will uninstall the stereo from the dashboard and connect it to the RCA outputs provided.

But if yours doesn’t come pre-installed with the RCA outputs then you are using a factory radio stereo which will require you to purchase a line output converter to carry out the RCA connections.

When connecting these cables, ensure they are separated from the power cable to avoid electric field interference when the amplifier is playing music.

Speaker Connections

The speaker wires are not print to signal interference like the RCA cables so they can be fitted anywhere without worries of the consequences in any of the chosen locations.

Using the recommended gauge sizes for the speakers and subwoofers respectively. Pass each output wires from the amplifier’s output and make sure the polarities (positive and negative terminal) of each wire is fixed respectively to the same polarity on the speakers to maximize music output.

Switching the car stereo system and adjusting the amplifier’s gain.

Now that all the right components have been connected from the battery to the stereo and from the amplifier to the speakers, with everything set to go. Ensure all wirings are done correctly and do not test or switch on the vehicle until you double-check your work.

Switch off all equalizers either from the stereo or amplifier and set the gain of the amplifier so the input and output levels will allow best music production and less background disturbances.


Now that you have gotten the knowledge you need, we hope you get to enjoy your stereo system to its fullest. If you have any problems re-check every step and ensure every one of them was followed.

We hope you find your installation process easy using this article. Feel free to share your thoughts in the comment section.

You can also check out how to power a car amplifier here.

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