How To Connect A Subwoofer to an Old Amplifier

Do you have an old amplifier that you want to make use of? Perhaps you found it in the attic covered in dust and want to connect it to your subwoofer? Or maybe you have bought a new subwoofer and want to connect it to your old amplifier but aren’t sure how? Whatever the reason is that brought you here today, we have the answer for you!

Do you have an old amplifier that you want to make use of? Perhaps you found it in the attic covered in dust and want to connect it to your subwoofer? Or maybe you have bought a new subwoofer and want to connect it to your old amplifier but aren’t sure how? Whatever the reason is that brought you here today, we have the answer for you!

We know how much of a headscratcher technology can be at times, and the last thing you want is to be frustrated sitting on your floor surrounded by wires. You want a simple solution that will allow you to connect your subwoofer to an old amplifier without losing days of your life to the task!

Well, luckily for you, you have come to the right place! Because we have three fantastic ways to connect a subwoofer to an old amplifier that will allow you to leave here today as a pro! Keep reading to find out more!

How To Connect A Subwoofer to an Old Amplifier

Before we get into connecting a subwoofer to an old amplifier, let’s discuss some factors that you need to be aware of. The first is that old amplifiers don’t have a subwoofer output like modern speakers or sound systems do, so we need to get creative in connecting them! 

The inputs and controls on the back of your subwoofer will differ, too, depending on the brand and model you have. Mostly you will find a power input, on/off switch, RCA input jack, a pair of jacks, a subwoofer crossover adjustment, and a subwoofer level adjustment on the back of your subwoofer.

These are usually labeled, but if not, you can identify them using the user manual of your subwoofer or by searching online for the make and model of your subwoofer. 

Understanding your subwoofer and its ports will make this task easier, so be sure to familiarize yourself before diving on in! It’s also worth checking your user manual to see if they have any guidance on connecting your subwoofer to older devices. They don’t always, but it’s worth having a read-through to check, just in case!

Now that we have covered some basics let’s move on and look at how you can connect your subwoofer to an old amplifier. Remember, the method you should use will vary depending on the subwoofer you have and its available ports/inputs. 

Connecting with RCA input jacks 

If your subwoofer has 1 or 2 RCA input jacks but no speaker level inputs, you can easily connect it to an amplifier using a line level converter.

These converters are small devices that connect to speaker outputs from an amp and scale down the higher voltage signal to a low level or line level. The outputs are RCA jacks which can then be connected to any amplifier or subwoofer with RCA jacks. 

Line-level converters are fairly affordable too, and you can pick them up in most stores or online! The price often relates to the quality of the converter, so if you can, opt for a high-end option to ensure you get a clear audio transfer. 

To use the line-level converter, you will want to connect the provided speaker wire connections (marked by colors and stripes) like you would with regular speakers. Then you connect RCA cables to your powered subwoofer. It really is that easy! 

If you have a subwoofer with a single RCA input jack, it might be worth picking up a Y RCA adapter to combine both receiver channels on the output side into a single mono RCA plug. If you run into any difficulties, there are plenty of tutorials and diagrams online that can help you! 

Connecting a subwoofer with speaker level inputs

Next, we have the easiest method, using speaker-level inputs to connect your subwoofer to your old amplifier. Simply connect the speaker outputs with a speaker wire and connect them to the matching inputs on the subwoofer. When doing so, you can even power speakers from the amplifier or receiver at the same time!

When using your speaker level inputs, the subwoofer’s internal electronics will scale down the speaker singles to a lower line-level signal that the internal amp can use. You will get nice sound quality from this method that you can now enjoy through your old amplifier! 

Connecting to a passive subwoofer 

If you have a passive or non-powered subwoofer, then you will need to use a different method to connect it to an old amplifier.

This can be done fairly easily by selecting a low pass crossover that will connect the amplifier and subwoofer. Connecting the two this way will filter out sounds above the crossover frequency and give you that nice bass sound that you crave! 

Crossovers are sold in single (one speaker) and dual (two speakers) models depending on the brand and supplier. You need to choose yours carefully, ensuring that it matches the sub’s impedance (Ohms rating).

For example, if you have an 8-ohm subwoofer, you will want a crossover designed for 8ohm speakers. If not, the sound filter will be different, and you won’t get the right sound!

It’s best to choose one with a low pass frequency close to 100Hz too. You might need to shop around to find one of these, so be sure to take your time and complete as much research as possible. You can usually find them online or in stores that sell speaker parts and components. 

Once you have your crossover, you simply connect it to the subwoofer and speaker, and you are good to go! If you run into any difficulties, there are plenty of tutorials online that can walk you through the process, but it should be a simple task! 

Final word 

And just like that, we have reached the end of our subwoofer journey today! As you can see, there are a few ways that you can connect your subwoofer to an old amplifier, depending on the make and model you have.

Be sure to familiarize yourself with the ports on your subwoofer, and don’t be afraid to ask for help if you need it! 

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