How to Hook up 2 Amps with 1 Power Wire – A Step by Step Guide

Welcome to the Ultimate Guide on How to Hook Up Two Amps with One Power Wire

If you’re like me and want to experience that extra oomph with your car’s sound system, you’ve definitely thought about exploring multiple amplifiers. But can you connect two amps to a battery with only one power wire?


To be honest, there are a few ways to set up two amps in your car, but using a single power wire is an easy and elegant way to pull it off. To use one power wire, you will need a power distribution block and a thicker wire gauge for the setup.

I researched to put up this simple guide to help you connect your two amps with one cable to your car’s battery. While the process might appear complicated, it’s in fact quite simple to do.

Show it to me already!

Steps on How to Hook Up Two Amps with 1 Power Wire

Hooking up an extra amp for your car’s sound system can make for a more well-rounded sound experience. You can achieve this setup in a few steps if you observe standard wiring practices.

To do this, you’ll need:

  • Power Distribution block- This device helps you to manage multiple devices like amplifiers. It has a direct connection to the battery and can be used to power various devices, such as your old and new amplifiers. Many such power distribution blocks come fused which helps safeguard the amplifiers in the event of a  short circuit.
  • Heavy gauge wire
  • Ground wire
  • Turn-on leads and relay

Step 1

Start by disconnecting your car’s battery. Either the positive or negative terminals of the battery can be removed, or the battery can be removed entirely. This will prevent any shorting from happening during your connection.

Step 2

Place the new amplifier in a fitting location, preferably beside the first one.

Step 3

Use a single power cable to connect your power block to your car battery. Use a heavier gauge for this setup, as you’ll need a wire that can meet the increased electrical demand of two amplifiers. Using a smaller wire will make the connection inefficient.

Step 4

Next, use two cables to hook up both amplifiers to your power block. Remember that the cables must be run through the firewall through the entire length of your amplifiers. You should use standard gauge cables for these connections.

Step 5

Create a ground connection for both amplifiers to prevent your power amps from retaining power and causing shocks. You can also utilize the power block for this, ensuring that you ground with a section of the chassis with bare metal. This can help you prevent ground loop issues.

Step 6

The next thing to do is connect a remote turn-on wire. However, it may not be effective for multiple amps. Thus, it’s best to get two turn-on leads for each amp and connect both to a 12 V relay that’s powered by your car’s head unit. Alternatively, you can hook up the relay to the car battery or fuse box.

Step 7

Connect the amps to the preamp outputs of your head unit. If your radio does not have multiple preamp outputs, you might need to use Y-cable adapters before you can connect your speakers.

How to Wire Two Amps Without a Distribution Block

If you do not wish to use a power distribution block, there are a few other ways to connect your amps to your battery. You can use active crossovers or a selector switch for this.

How to Use Active Crossovers

Using active crossovers means you’ll have to connect an amplifier to the subwoofers and another amp to high-frequency speakers.

Simply connect the R and L head units to their respective crossover inputs. Then, connect your high and low output signals to your tweeters and subwoofers. Next, play some music to test the amp and adjust the knob to suit your preferences.

How to Use a Selector Switch

With a selector switch, you can connect two amps but cannot use both simultaneously. To set it up, simply link the amplifiers with the input sockets in the back panels. Then, connect the speaker wire to the A input, and the R and L inputs to the corresponding outputs. Then connect the speaker wire of the second amp to the B input socket.

After connecting both speaker wires, connect the speaker wire of your switch to your speaker input. Then, switch between amplifiers with the selector switch.


Frequently Asked Questions

Can you hook two amps together?

You can connect two or more amplifiers to the car audio system, and there are several ways to do this. As shown above, you can connect two or more amps to one power source using a power distribution block. This block relays power into all your amps equally.

If you want to hook up your amps to your head unit and your head unit does not have multiple preamp outputs, you might be able to connect both amps to each other. Some amps have preamp pass-through functionality that lets you connect multiple amps to each other.

If your amp has this functionality, simply connect the pass-through outputs of one amplifier to the preamp inputs of the other. If you have more amps, continue this loop until all amps are connected.

Can I hook up 2 amps with 1 RCA?

The RCA cable must be split in half in order to connect the two amplifiers. You can use RCA splitter cables, line output converters, or a daisy chain connection to achieve this.

An RCA splitter cable is a 2-in-1 cable that allows you connect two cables to one RCA port. It’s best to go with a line output converter if your system does not have a jack.


Sometimes (especially if you’re an audiophile), you need that extra something to make your car’s audio experience more enjoyable. Installing two amps in your car is a great way to achieve this if a single amplifier seems not to be cutting it. With the technique above, you can easily connect two amps to your car battery without hassle.

This guide shows you how to wire two amps to one head unit using a power distribution block. Also, if you do not wish to use a power block as prescribed, you can install multiple amps using active crossovers or a selector switch. Choose the procedure you prefer and enjoy an enhanced sound experience during car rides.

Last Updated on February 4, 2023 by Danny Reid

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!