How to Add an Amplifier To Your Factory Car Stereo System – Keep Your Radio & Speakers

How to Add an Amplifier To Your Factory Car Stereo System

So you want an amplifier and subwoofer or an amplifier for your factory car speakers installed but you want to keep your factory stereo and/or the speakers your vehicle came with. There are a few ways to do this, but its important to understand your limitations.

Before starting I need to mention that you’ll need a few tools for the job that can all be found in our installation resource page.

Ill also need to mention that we recommend you find a wiring diagram for your vehicle before you start and call your manufacturer to verify whether or not you have a premium audio system currently in your vehicle. If you do this changes everything.

When Do You Need To Add an Amplifier To Your Factory System?

Simply put, whenever you want. Generally speaking you should consider adding an amplifier whenever the clarity and/or volume inst to your liking. You can also consider adding a subwoofer amplifier to your system paired with a nice subwoofer to bring the bass presence up to your liking.

But, and there’s always a but… there are times it might be counter intuitive to add an amplifier to your system. Here’s a list of situations where you should probably consider options other than adding an amp to your factory system.

When You Shouldn’t Add an Amplifier To Your Factory System

  • If you have a factory premium amplified system. (Will need to bypass the current amp before adding another)
  • If one or more speakers are faulty.
  • If your vehicle has a faulty or non operational radio.
  • If your vehicle was made before the year 2000. (speakers and/or wiring might be old and brittle)

What Amplifiers Can You Add To Your Factory Audio System?

The short answer is, any. But, there are a few styles of amplifiers that make it a lot easier to integrate with the factory system without the need to replace any existing things.

  • Subwoofer Amplifiers – Amplifiers dedicated to powering subwoofers
  • 2 channel amplifiers – Amplifiers that power 2 speakers
  • 4 Channel amplifiers – Amplifiers that power up to 4 speakers
  • 5 channel amplifiers – Amplifiers that power up to 5 speakers including 1 subwoofer

While almost every amplifier is capable of being installed into a factory audio system when paired with the right accessories, there are some that were made specifically for it! Here are the two we tend to favor the most:

Kicker Hideaway – Self Powered Subwoofer with Amplifier

The Kicker Hideway is a self powered subwoofer. Meaning, it is a subwoofer in an enclosure with an amplifier already built in. This type of unit makes these types of installations a lot easier because of its wiring options, size and small footprint. You also do not need an aftermarket radio in order to use this system because it has an internal Hi Lo converter.

Alpine power pack review

Alpine Power Pack – Mini 4 Channel Amplifier

The Alpine Power Pack is another amplifier that has made factory integration way easier! it has a internal Hi/Lo and comes with an input and output harness that will usually allow you to install it without any additional parts even. Its considered a mini amplifier because of its small footprint and can generally be installed into hidden locations around your car.

What Parts Do I Need To Install an Amplifier Into My Factory Audio System?

Its important you know that not all amplifiers require the same parts during installation. For example, the Alpine Power Pack 4 channel amplifier comes with the mounting parts, wiring and fuse needed to install right out of the box while standard amplifiers might need a few more things. Lets name off the parts we use for standard amplifiers when integrating with a factory system.

Parts You Need When Integrating a 4 Channel Amplifier To Your Factory system

Parts You Need When Integrating a Subwoofer Amplifier To Your Factory system

If you are installing a 5 channel amplifier your amplifier will create a subwoofer output for you. This channel usually takes the sum of your rear/front or both amplifier inputs to create a proper subwoofer output channel. You won’t need anymore RCA input wires, just a bit of subwoofer speaker wire.

How To Add Your Amplifier Into Your Factory Audio System

First its important to plan your installation. Verify where your going to run the wires and if you have the proper length wires for the job. If you are installing a subwoofer be sure to verify you have enough room to mount the sub box once you install the sub into it. Be sure to have your wiring diagram for your vehicle ready to refer to. After you’ve verified these things start on the first step below:

How to Install 4 Channel Amplifiers Into Your Factory System

How to Add an Amplifier To Your Factory Car Stereo System
  • Remove your factory radio and locate your speaker wires coming from the radio side using your wiring diagram
  • If you are using a 4 channel Hi/Lo splice these wires and connect them to your hi lo
  • If your amplifier has an internal Hi Lo you will need to cut your speaker wires and attach them to the amplifier input wire harness listed in the parts list at the top of the page.
  • Run those wires to the amplifier and connect them into the input section of the amplifier
  • Now connect your second harness to the speaker wires that lead into the dash and run them to the output section of your new amplifier.
  • Connect your remote wire to a 12v switched source that only powers when the car is running and run that down with your other wires to your amp and connect that to the remote wire input on your amp.
  • Run your 12v batter wire from your battery to your amplifier.
  • Connect your ground wire to a chassis ground in vehicle free of paint.

How To Install Subwoofer/Mono Block Amplifiers Into Your Factory System

The process of installing an amplifier for your subwoofer is almost identical to a 4 channel amplifier. The difference is in the input and output section. Instead of cutting input behind the radio, you are just splicing or sharing signal to your amplifier.

Additionally you will not need to run the out put back to the harness behind the radio. You will just need to run the larger gauge speaker wire from your amplifier to your subwoofer. This is usually a lot easier!

  • Connect your 2 channel HI/lo converter to a left and right output signal behind your radio.
  • Attatch your RCA wires to that RCA channel and run that to the input section of your amp
  • Run your remote wire from a source that has 12v only while the vehicle is running to your amplifiers remote input
  • run power wire from battery to amp
  • Run ground wire from proper chassis ground to amp
  • Run speaker wire from amp to subwoofer