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How to Connect 2 Car Amplifiers Together?

Are you looking to get the most out of your car’s audio system? Imagine being able to amplify the sound of your favorite tunes with two car amplifiers connected together.

Connecting two car amplifiers will increase volume and provide a much more dynamic listening experience, but how to do it correctly? Let’s find out.

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To connect two car amplifiers together, follow the steps below:

#1. Find a suitable location for the second amplifier, ensuring enough space and secure mounting.

#2. Use a “Y” adapter for the RCA cables, connecting one end to the car stereo preamp outputs and two others to both amplifiers.

#3. Use a power distribution block for the power and ground wires. First, connect the power wire from the head unit to the block, and then connect the power wires from both amplifiers to the block. Similarly, connect the ground wire from both amplifiers to the block.

#4. Turn on the head unit and test the amplifiers to ensure they function correctly.

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In this article, I will go over the steps and materials you’ll need to successfully connect two car amplifiers together, as well as tips for troubleshooting any issues you may encounter.

How Do I Connect Two Car Amps Together?

If you’re an audiophile looking to take your car audio system to the next level, consider connecting two car amplifiers together.

This can be a great way to increase the power and versatility of your system, allowing you to drive larger or more speakers or fine-tune your system’s sound by using different amplifiers for different types of speakers.

However, it’s important to do it correctly to avoid damaging your amplifiers or creating other issues. So let’s start with all you need for a good installation.

Materials Needed

To connect two car amplifiers together, you’ll need the following materials:

#1. “Y” Adapter

This splitter allows you to split the signal from your head unit and send it to two amplifiers.

Many different “Y” adapters are available on the market, but choosing a high-quality one is important to ensure a stable and reliable connection. Of all I tried, I recommend InstallGear (link to Amazon).

#2. RCA Cables

You’ll need a set of RCA cables to connect the “Y” adapter to the amplifiers and the head unit.

RCA cables are a common type of audio wires that are designed specifically for transferring audio signals.

When shopping for RCA cables, look for ones of high quality and with good shielding to avoid any engine noise issues. My favorite ones are Knukonceptz Klarity (link to Amazon).

#3. Fuse Holder and Fuses

A fuse holder is a device that holds the fuse in place and allows you to easily remove and replace it if necessary.

Fuses are designed to “blow” or break the electrical connection if the current flowing through them exceeds a certain level, protecting your system from damage.

When shopping for a fuse holder and fuses, look for ones with the size compatible with your amplifiers and that have good reviews. One of the most recommended are from InstallGear (link to Amazon)

#4. Power Cables

You’ll need a set of power cables to connect the amplifiers to the car battery.

Good power cables are a must-have to carry higher amounts of current. When shopping for power cables, look for OFC ones, like KnuKonceptz Kolossus Flex (link to Amazon).

#5. Speaker Wires

When you use an amplifier, ensure the speaker wires have the correct gauge and are good quality.

For most aftermarket car speakers, AWG16 will be enough, but for the subwoofer, you may need AWG12 or even AWG10.

I use Knukonceptz Kord Kable (link to Amazon) for all installations, and I am happy with their robust design and flexibility when running through tight spots.

Steps to Connecting Two Amplifiers Together

Here are the steps to connect two car amplifiers together:

#1. Connect the Head Unit to the “Y” Adapter Using RCA Cables.

Start by locating the RCA outputs on your head unit. These are usually labeled as “front,” “rear,” or “subwoofer,” and you may see them on the back of the stereo.

If you have all those RCA outputs on the stereo and use a mono amp with multi-channel, you do not need the “Y” adapter because all channels will directly connect with the amps.

If, however, you use two multi-channel amps or two monoblocks, you need to split the signal for them.

In this case, connect one end of each RCA cable to the corresponding output on the head unit. Then, connect the other end of each RCA cable to the “Y” adapter.

#2. Connect One End of the “Y” Adapter to the First Amplifier Using RCA Cables.

Once you’ve connected the head unit to the “Y” adapter, you’ll need to connect the “Y” adapter to the first amplifier.

To do this, connect one end of each RCA cable to the corresponding input on the amplifier. Then, connect the other end of each RCA cable to the “Y” adapter.

#3. Connect the Other End of the “Y” Adapter to the Second Amplifier Using RCA Cables.

Now it’s time to do the same with the remaining part of the “Y” adapter and the second amplifier. 

Connect one end of each RCA cable to the corresponding input on the amplifier. Then again, connect the other end of each RCA cable to the “Y” adapter.

#4. Connect Both Amplifiers to the Car Battery Using Power Cables.

Once you’ve connected the amplifiers to the “Y” adapter, you’ll need to connect them to the car battery. To do this, you have two options.

It’s usually best to use a single power cable that feeds both amps, but you might need to use a thicker gauge cable to handle the high current draw, and the fuse that can protect the system should be appropriate for the combined load of both amplifiers.

Alternatively, you could run separate power cables for each amp directly from the battery. In this case, you’ll need a fuse holder and fuses for each amplifier.

#5. Connect the Ground Wire From Each Amplifier to the Car’s Chassis.

You need to ground each amplifier to the chassis, but instead of grounding them individually, it’s usually better to use a ground distribution block and connect the individual amps to that.

That way, you can connect your other audio components to the same block and avoid any ground loop issues. Remember that the gauge of the ground wire should be the same as the power wire.

#6. Connect the Speaker Wire From Each Amplifier to the Corresponding Speakers.

When using two amplifiers, you need to know which one will work with which speaker.

The most popular combination is a D-class monoblock for the subwoofer and a four-channel A/B class amp for the rest of the speakers.

Connect all amps’ terminals to the corresponding speakers, and you’re done, but make sure to use the correct wire gauges.

#7. Turn on the Head Unit and Test the System to Ensure Everything Is Working Properly.

Once you’ve connected everything, it’s time to test the system to make sure everything is working properly. To do this, turn on the head unit and play some music but do not turn the volume too high.

If everything is connected correctly, you should be able to hear the music through the speakers.

If you’re having trouble getting the system to work, double-check all the connections to ensure they’re secure and properly connected.

Safety Tips and Precautions

Here are a few tips and precautions to keep in mind when connecting two car amplifiers together:

#1. Use High-Quality Materials

It’s important to use high-quality materials to connect two car amplifiers to ensure a stable and reliable connection.

Look for high-quality and reputable “Y” adapters, RCA cables, fuse holders, power cables, and speaker wires. This will help to reduce the risk of issues such as signal loss or electrical problems.

#2. Follow the Manufacturer’s Instructions

Each amplifier is different, so it’s important to follow the manufacturer’s instructions when connecting them.

When in doubt, come back to the connecting diagram. It is better to double-check than be sorry when the amp burns out.

#3. Be Careful When Working With Electrical Components

When working with electrical components, it’s important to be careful and follow proper safety procedures.

Always turn off the car and disconnect the battery’s negative terminal before working on the audio system. Also, wear protective gear such as gloves and glasses if necessary.


In conclusion, connecting two car amplifiers together can be a great way to increase the power and versatility of your car audio system. 

Follow these steps and use high-quality materials, and you’ll be well on your way to enjoying your upgraded car audio system.

Wiring in multiple amps can be a headache, but with careful planning and attention to detail, you can get a top-notch sound system.

Follow proper safety guidelines and consult a professional if you need clarification.


How Do I Connect Multiple Power Cables to My Amplifiers?

To connect multiple power cables to your amplifiers, you will need to use a distribution block.

A distribution block allows you to connect multiple cables to a single connection point.

For example, you will need to connect one power cable from your battery to the distribution block and then connect the other power cables from the amplifiers to the distribution block.

Use proper wire sizes and follow the manufacturer’s recommendations for your amplifiers.

How Can I Make Sure the Amps Are Properly Grounded?

To properly ground your amplifiers, you will need to connect the ground wire from each amplifier to a clean, bare metal surface on your car.

This could be a grounding point on the frame or chassis of the car or a separate grounding block you install.

A good ground connection is critical to ensure that your amplifiers run safely and efficiently.

How Thick of a Power Cable Do I Need for Two Car Amplifiers?

The thickness of the power cable you need for two car amplifiers will depend on the current draw of your amplifiers and the length of the cable.

Generally, you should use a thicker cable for longer runs or amplifiers with a higher current draw. Follow the manufacturer’s recommendations for your amplifiers and use the proper wire size.

How Do I Avoid Ground Loop Issues When Connecting Two Car Amplifiers Together?

To avoid ground loop issues when connecting two car amplifiers, you should ground both amplifiers to the same point on the car.

This will help to ensure that both amplifiers are running at the same electrical potential and prevent any grounding issues.