Can I Install Multiple Amps In My Car?

Can I Install Multiple Amps In My Car?

A common question most people new to car audio want to know is whether they can install multiple amps, or if they’re limited to just one amplifier in their car.

Upgrading your car stereo system with an amplifier and extra speakers makes a huge difference to your listening experience. Most audiophiles build an aftermarket car stereo system steadily, but what happens if you want to add a second or even third amplifier.

Is that even possible in a vehicle? Well, the answer to that is a resounding yes, but there are a few things you have to consider.

The most common reason to wire in more than one amp is having a multi-channel amp for your main speakers and a second monoblock amplifier for a subwoofer.

Multi-channel amplifiers are getting better and some even utilize both A/B and D technologies to make them better for anyone wanting the best and most efficient amplifiers for their specific drivers.

Some people don’t like to use just one amp for a full car stereo system, however.  And there are benefits to using more than one amplifier. If that’s you, there are some things to think about before you get a second or third amp.

Things To Consider…

To install more than one amplifier in your car, you have to consider things like space, if your power cable is sufficient, the grounding of each installed amplifier, and whether the remote turn on is capable of running more than one amp.

If you do decide to go with multiple amps, the process of multi-amp wiring is similar to single amp setups. You have a couple of options, but it’s important to take the increased current draw into account in any case.

Your car charging system must be powerful enough to run multiple amps. And if you find your amps running too much juice, you may have to upgrade your alternator or get an outboard capacitor which will give your amp a boost of power when needed.

Pros and Cons of Multiple Amps vs One Multichannel Amp

There are benefits to both installations, and many people opt for one reason or another because of finances, but if you’re upgrading you should really spend that little bit extra if it benefits your system.

The benefits of installing multiple amps is that your drivers will likely sound better and louder, especially your subwoofer. Most 5-channel amps are good enough for most people, but the sub channels are limited compared with the best monoblock amps.

The clarity of your music, therefore, should improve, but don’t think a multi-channel amp won’t do a good job because it will and the difference won’t be a big factor unless you’re a true audiophile.

Of course, if you have more than one amp and one breaks you can simply replace that amp. If you only have say a 4-channel amp running your system and it breaks, you have to replace it, but they are more expensive than single or 2-channel amps.

The main benefit of having a multi-channel amp is it should take up less space, so if you have a small trunk this should be a consideration.

A single amplifier is easier to install, too. It shouldn’t be a big factor in your decision, but you won’t have to get a power distribution block or any extra equipment to split the wires.

Wiring Multiple Amps

If you’re wiring one or multiple amps, the practice should be the same for the installation. This means getting power from the battery and run either a single cable to all of them, or a separate cable for each amplifier.

Personally, I prefer to use the single cable option, as it’s a cleaner set up. For this way, make sure you get the thickest wire gauge that will work for your system. The size of the power cable you need will depend on the overall current demands of all the amplifiers in your system.

To work it out, there’s a few different factors to think about, such as length of wire, how efficient are your amplifiers, what resistance etc. There’s a chart below, which is a good guide. It’s based on a ½ volt loss in your power cable and as you can see the general efficiency loss of both an A/B and D amplifier.

Multiple Amp Wire Gauge Chart

There’s also good wire gauge calculator, here, but generally if you’re installing multiple amps you will need something bigger than what your single amp manual says. So, if your manual says to use an 8 or a 4 AWG power wire, you may need to use 2 AWG or 1/0 AWG main power wire.

You will run that thicker wire from your battery, through your firewall and connect it to a fused distribution power block. This distribution block should be as close as possible to the amplifiers, and your single cable should be the longest of each power cable.

The power block can also be used as a grounding connection to your chassis, and you can also use this for any other car audio parts if need be.

On the output side of the power block, you’ll have two wires going to both your amplifiers, and these should be a smaller AWG, the one your amplifier manual actually recommends.

Check out this article for installing an amplifier in your car.

Wiring The Remote Turn On Wires

If you’re running multiple amps, you might find that one remote turn on wire isn’t suitable and so you’ll need to wire both amps to your head unit.

The cleanest way of doing this is to run a single turn on wire from your head unit to a relay, which will allow you to run a separate amp remote wires to each amplifier.

You should connect the relay to the fuse box or directly to your battery, which will ensure you never get any current overload.

multi amp wiring diagram

If your head unit doesn’t have a remote wire, you’ll have to connect it to the fuse box. For full information on this check this article out.

Wiring Your Amps and Head Unit Together

The way you wire your amplifiers to the head unit will depend on the system you have. If you have a good quality aftermarket car radio it should have enough preamp outputs, which will give you the cleanest of connections from each piece of equipment.

If your head unit doesn’t have enough preamp outputs, you may be able to connect your amps by connecting the pass-through outputs on your first amp to the preamp outputs on your other amplifier.

If your amps don’t boast the pass-through functions, you could always use a Y adapter to split the signal between your amps and run this to your head unit.

If your head unit doesn’t have preamp outputs at all, you might have to use a Line Output Converter. This will allow you to tap into your speaker wires and create an RCA output. If you’re looking to install a Line Output Converter, check out this article for a step-by-step guide.

Installing Multiple Amps Is Doable and Can Enrich Your Soundstage

As people seek the very best sound system for their car, they look to upgrade their equipment. Aftermarket speakers deserve an amplifier, and of course a subwoofer needs an amplifier.

You can get multi-channel amplifiers of course, and they are excellent and better for many people. But if you already have an amplifier, and don’t want to spend all that money on a multi-channel when you can get a monoblock or 2-channel amp, then that’s also fine.

It just takes a bit more wiring, devices to distribute the wiring separately, but the set-up is pretty much the same as a single amp set-up.

Whichever way you go with, you should definitely start upgrading your sound system, because the difference will be mind-blowing.

How about making your car speakers louder without an amp! It can be done, check this article out for information…

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