How to install an amplifier (with pictures)

Table of contents:

How to install an amplifier (with pictures)
How to install an amplifier (with pictures)

If you are an audiophile or want to upgrade your vintage car or home theater system, an amplifier will not only increase the volume of the speakers, but it will also improve the sound quality. Before installing, make sure you know the power of the audio system and the speakers. Set a budget that helps you manage your expectations, and always consult your owner's manual to ensure your safety.


Method 1 of 2: Install a Car Amplifier

Install an Amplifier Step 1
Install an Amplifier Step 1

Step 1. Determine the capacity of your vehicle

Check your owner's manual to determine the power of your speakers. Consider how much electrical power the current system can handle.

  • First of all, how loud do you want the stereo sound to be? The amount of wattage does not necessarily determine the car's audio power. However, having a large amount of available power will be adequate for headroom, which is the ability to transmit a burst of sound when needed depending on the music.
  • Take into account the size of your car, as in the case of a smaller one, you will also need a smaller amplifier for your system. For example, a 50 watt RMS (mean square value) amplifier per channel or a smaller one can overcome loud road noises and provide greater clarity. Make sure you use speakers that have a maximum RMS power rating of at least 35 watts.
  • If your vehicle is larger or if you just want more volume, opt for an amplifier rated at about 75 watts RMS for each set of channels. Amplifiers of this size will require speakers that have a maximum RMS power rating of 50 watts RMS or more.
  • If you want the highest volume possible, an amplifier rated at 100 watts RMS or more per channel will really make you stand out. Speakers or sets of components rated at least 75 watts each will be able to support an amplifier of this rating.
Install an Amplifier Step 2
Install an Amplifier Step 2

Step 2. Choose the type of amplifier

Amplifiers can be categorized into a 4-class system based on efficiency, size, and price.

  • Class A is 25% efficient, which means that for every 100 watts of electricity used, only 25 of those watts are consumed by the speakers. These amplifiers are considered low quality and are not suitable for cars.
  • Class A / B amplifiers are 50-60% efficient in terms of power use. They are generally smaller, use less power, and cost less than Class A designs. Most car audio amplifiers are of this type due to their efficiency and compact size.
  • Class D is known as a switching amplifier that works well as a subwoofer. This class of amplifier has better efficiency in a smaller size than the class A / B ones. When it comes to power usage, these amplifiers are 70-75% efficient.
  • Class G / H designs use multiple levels of output voltage and are 75-80% efficient. At low volume, these amplifiers maintain an equally low voltage. As you increase the volume, the amplifier uses the second (highest) voltage level and, at maximum volume, all voltages combine to maximize your output. These amplifiers are smaller and have a relatively higher power output compared to class A / B ones.
Install an Amplifier Step 3
Install an Amplifier Step 3

Step 3. Choose the location where you want to place the amplifier inside your car

The amplifier should be located at least 3 feet (90 cm) away from the receiver to eliminate distortion from the vehicle's electrical system.

  • Do not attach the amplifier directly to the metal chassis of the car, as noise problems are easy (eg, ground loops that emit hissing or buzzing sound). Use rubber washers around the mounting screws to isolate the frame, or put the amp on a wooden board and then attach it to the car.
  • Keep the amp cool. An amplifier produces heat, which absorbs and radiates its heat sink, so it is necessary to keep a few centimeters of free space around it in order to allow heat dissipation. If you are going to mount the amplifier on the wall of your car, keep the location of the heatsink fins in an upright position. Also, never turn it upside down, otherwise the heat will not be able to dissipate, rather it will return to the amplifier.
  • Make room on each side of the amplifier for wiring connections. You also need enough space to adjust the controls for gain, crossover, bass boost, etc.
  • The common places to place the amplifier are under the seat or in the trunk, so it is possible to easily hide the cables and have easy access to the controls.
Install an Amplifier Step 4
Install an Amplifier Step 4

Step 4. Disconnect the negative pole of the car battery

Use a 1/2 inch (13 mm) wrench to loosen the negative pole clamp, and then remove it from the battery with your fingers. If it is stuck, use a pry bar to free the end of the cable located on the pure lead battery.

  • Make sure to disconnect the negative pole first. If the key slips while you disconnect the positive pole, it can form an arc that will give you an electric shock.
  • Take off all jewelry, especially rings. If you suffer an accidental electric shock, the heat produced can melt the jewelry on your skin.
  • Check the owner's manual, but generally the positive is red while the negative is black. You should also look for the positive (+) and negative (-) signs.
Install an Amplifier Step 5
Install an Amplifier Step 5

Step 5. Drill a hole in the firewall of your car to pass the power cord of the amplifier

Use a drill and steel bit to create a pilot hole, then use larger bits to expand the pilot hole to just enough width for the cable to fit after fitting a rubber grommet. Make sure the hole is free of sharp burrs so you don't cut the amp wires. Connect the amplifier's power cable from the positive slot to the corresponding positive terminal on the battery.

  • To determine which is the positive terminal of your amplifier, look for the red sign or the "+".
  • Use a rubber grommet to keep the cable from friction, otherwise it could cause a fire.
  • Check the area before drilling, as you will want to avoid contact with wires from other components.
  • Insert a fuse in the battery to protect the car from fires, as well as another one in the amplifier to protect it in case of a short circuit.
Install an Amplifier Step 6
Install an Amplifier Step 6

Step 6. Connect the power cable to the positive terminal of the battery

Remove the terminal nut. Then slide the power cord over the bolt that secures the terminal to the battery post and replace the nut.

  • Many cables that come in wiring kits come with circular terminals. If you don't have one, loop the end of the power cord before continuing.
  • Make sure the cable is not compressed, kinked, or rubbed while driving.
Install an Amplifier Step 7
Install an Amplifier Step 7

Step 7. Ground the amplifier for safety

Use a bolt from the metal frame of your car that is as close to the amplifier as possible. If you can't find one, drill a hole and put in a ground screw or bolt, but check the location of the wiring, fuel tank, or brake line before drilling. Wrap a circular terminal around the short end of the ground wire.

  • Before installing the bolt, scrape off the paint and thoroughly clean the place on the structure where you are going to make the ground connection. Keep the connection tight, clean, and electrically conductive with the help of a lock washer, star washer, extra screws, or some other grounding technique. Washers are cheap and sold at hardware stores. They are also known as "O-rings".
  • Do not use any bolt that belongs to the seat belt, otherwise it may compromise its integrity and your safety.
Install an Amplifier Step 8
Install an Amplifier Step 8

Step 8. Mount the amplifier in the car using self-tapping screws

If these screws are not included in the amp installation kit, you can purchase them from a hardware store. Then line up the amp and fit the screws, making sure there is adequate space for them and that they don't come into contact with anything other than the metal frame.

Install an Amplifier Step 9
Install an Amplifier Step 9

Step 9. Connect the power and signal cables to the amplifier

Trim each wire well, place them in the desired position and connect them. If necessary, curl them gently, because if you make very rough ones, you could compress them. Make small cuts in the vehicle's carpet so that you can route the cables underneath for a neat, professional appearance.

If you don't have the right tools, use an uncoiled wire hanger to run the cord under the rug

Install an Amplifier Step 10
Install an Amplifier Step 10

Step 10. Connect the amplifier to the rest of the sound system

Pass each wire for the door speakers through the grommet to protect them from inclement weather or being crushed in the door. Remove the factory cables and connect the new ones (the ones that are connected to the amplifier) directly to each speaker terminal.

  • Use a 14 or 16 gauge wire for the speakers and a 12 or 14 gauge wire for the subwoofer.
  • It is important that you maintain the negative polarity of the speaker wiring by making sure that the positive terminals are connected to each other as well as the negative ones. This will ensure that all speaker cones have the same signal type and move in the same direction, thus creating a balanced sound each time they work together.
Install an Amplifier Step 11
Install an Amplifier Step 11

Step 11. Connect the battery and ignition

Start the car and then the radio. There is an indicator light on the amp that will tell you if the amp is on. Increase the volume to an audible level and make sure the sound is coming from each speaker or subwoofer in the system.

Make sure all the amp settings are at the lowest level before turning on the stereo

Method 2 of 2: Install an Amplifier for a Home Theater System

Install an Amplifier Step 12
Install an Amplifier Step 12

Step 1. Consider the type of amplifier you will need for the capacity of your home theater system

Depending on your budget and desired sound, your home theater will need a specific amplifier and preamp for your needs. An amplifier increases the power available to the speakers, while a preamp controls everything and needs both an amplifier and a speaker to function.

  • A tube amp uses a vacuum tube, so a single ended triode tube amp works well in conjunction with high-efficiency drivers.
  • FET (Field Effect Transistor,”a name given to it because it uses an electric field) amplifiers are a popular type of solid-state amplifier.
  • Class A amplifiers produce almost no distortion with a maximum amount of power.
  • Class B amplifiers produce a bit of distortion and need to be turned on.
  • Class AB amplifiers are a combination of the above two, where a signal alternates between a class A circuit and a class B circuit.
Install an Amplifier Step 13
Install an Amplifier Step 13

Step 2. Choose the type of configuration for the amplifier

Amplifiers have many different configurations that can depend on the number of speakers, the type of speakers, and the layout of the space.

  • If you only use a couple of speakers, stereo amplifiers are the common choice.
  • If you have a series of different high-power speakers, it is possible to configure monoblock amplifiers for each one.
  • If your home theater system is advanced and has 5 or more inputs, multichannel amplifiers are the most suitable.
Install an Amplifier Step 14
Install an Amplifier Step 14

Step 3. Organize your team

Your equipment will depend on the complexity of your home theater system, but the basic requirements are input sources, amplifiers, preamps, and cable connectors.

  • The input sources are the devices that you will connect to the speakers, such as Blu-Ray players, DVD players, and stereo equipment.
  • Cable connectors should come with input sources, but if you need more or need longer ones, go to a local home theater specialist.
Install an Amplifier Step 15
Install an Amplifier Step 15

Step 4. Locate the preamp inside your home theater system

It should be in an easily accessible location with enough space for the input and output cables.

If you have a cabinet home theater system, make sure there is an opening in the back or remove any covering that could obstruct the cables

Install an Amplifier Step 16
Install an Amplifier Step 16

Step 5. Arrange the cables

Depending on the number of input sources you have, you will probably need to label each cable. This is why you will need to organize the cables as you connect them to the amplifier.

Place masking tape near the connector pin and label each source

Install an Amplifier Step 17
Install an Amplifier Step 17

Step 6. Connect the input sources to the preamp

Route the cables from the back of the input devices to the input jacks on the preamp.

  • Make sure you use the correct cable and connect it to the correct input on the preamp as there can be a lot of them.
  • Make sure the plug is properly connected to the slot.
Install an Amplifier Step 18
Install an Amplifier Step 18

Step 7. Connect the preamp to the amp

Connect the cables from the preamp's output terminals to the input jacks on the back of the amplifier, which should be connected to the speakers via the output terminals.

Do not connect a 2-channel amplifier to more than 2 speakers, otherwise it could be damaged

Install an Amplifier Step 19
Install an Amplifier Step 19

Step 8. Power on the system

Choose the input source and turn on both the amp and preamp. Never connect the amplifier while the power is on, otherwise it will create a power surge and, depending on the volume control, an unpleasant sound will be produced.

While any amp can be paired with any preamp, both can also come as a single integrated unit. The difference between a unit and a 2-piece combination is the flexibility you will have when setting up your home theater and the power you can achieve


  • Buy an amplifier that is the correct size for the power the speakers can handle. Too much or too little power will damage the speakers.
  • Always use a wire of sufficient gauge for the power of the amplifier. Consult a professional or do an internet search.
  • If the amplifier is going to be in a small area without air circulation, use a fan, otherwise overheating will end up damaging it.
  • The speakers are rated for ohms, and the amplifier is rated to work with a certain type of speaker. Therefore, make sure they are compatible.


  • Overheated circuitry can shut down the amp, but damage can occur sooner than that.
  • Follow the manufacturer's recommendations for assembly of the amplifier and make sure it is safe. A loose amplifier during an accident can injure a passenger while moving through the vehicle.
  • For safety reasons, always double check that the wiring is secure before powering up the system.
  • A difference of 5 or 10 watts will not vary significantly in sound, as it will probably not even be heard.
  • Amplifiers can interfere with AM and FM radio reception.

Popular by topic