How to Connect a Subwoofer to an Old Amplifier with Results

How to Connect a Subwoofer to an Old Amplifier

Do you have an issue connecting your subwoofer with your vintage receiver? Many people do but learning about the input and output jacks in each device will help you succeed with this project.

Most modern subwoofers come with a built-in amplifier, but you can always find subs without amps. You may have a subwoofer and an old amplifier that you want to connect to a speaker. Can they work together? Yeah, find out how to connect a subwoofer to an old amplifier with results.

Basically, with that old amp that you own, you can connect to your sub and speaker systems using the RCA jack outputs or Speaker outputs. The port you use will depend on the subwoofer and amp you are connecting.

One thing is worthy of note about vintage receivers. They don’t have equalizers that help them balance out the gain on the subwoofer. Thus, if you raise the sound of the receiver, the subwoofer will be affected. In fact, it will cause the bass sound to become louder than what it should be and that will be quite unpleasant. So, you need to be careful with this connection.

Here in this article, you’ll see how to run various vintage amps to subs.

Prefer Videos? Here’s how to connect your subwoofer to an old amplifier

What’s the General Way to Connect an Amplifier and a Subwoofer?

Passive subwoofers require external amplifiers to relate with an input and output system. For your receiver to bridge the gap between the subwoofer and other systems, you’ll require RCA cables to pass between the amplifier and the subwoofer, speakers, and speaker wires. This is if the receiver has the RCA jack. An RCA cable set is a jack of yellow, white, and red terminals.

If you’re running the sub in your room, then think about placement while considering the connection. Start with passing your receiver into the sub with the RCA cables. While one set of RCA cables will give you a good output, if you want a richer output – like deep, clear sounds – use two RCA cable sets. Pass the input channel of the receiver into the output channel of the subwoofer.

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For most amplifiers, the RCA jack may be indicated with the caption “subwoofer output“. However, before you start your connection, ensure you turn off your amp and subwoofer then unplug them from any source of power.

When those two are connected, run the receiver to the speakers. The speaker outputs of the amplifier are usually built-in behind it. You’ll have to run the speaker wires (which are bare at the ends) into each of the speaker outputs. Run the right output speaker wire into the right speaker and run the left output speaker wire into the left speaker. If you have receivers with defined negative and positive terminals, then run the positive and negative terminals of the speakers into the receiver.

When you are done with the connection, plug the amp and sub back to their power source and switch them on.

Connecting a Vintage Amplifier to a Powered Infinity Sub

There are a number of ways that you can connect your vintage amplifier to a powered subwoofer. First, if your amplifier has 2 preouts then you can pass RCA cables from those to the low level input of your subwoofer. In this case, for passing the amplifying devices with preout/main-in loops, you need a Y adapter that will serve as the RCA cables set so that you will pass the double end between the preout and the subwoofer while the second end runs into the main-in of your device.

If your amplifying device does not have Preouts or main-in, then use the Speaker Inputs Channel. These will allow you to pass speaker wires between the subwoofer and the other device. At the same time, you can pass your subwoofer into the main speakers through the speakers out (also called high level output).

Video: Connecting a Subwoofer to a Vintage Amplifier

This video will show you how to connect your sub with your vintage receiver

Connecting a Subwoofer to a Vintage Amplifier Without an Out

Even without a subwoofer out, you can connect your vintage amplifier to your subwoofer using the preamp output. Just to buttress, if the receivers have output then get a pair of interconnects and pass them from the Preout into the subwoofer. You may find the preamp output labeled as “Pre Out” on some amplifiers. For subwoofers with only one RCA input, you need the Y adapter. It has a male RCA at one end while the second end has two female RCAs.

In the event that your amp lacks the preamp output, then you can run the connection as if your subwoofer is a normal speaker. In this case, pass speaker wires from the speaker terminal of the amp to the speaker-level terminal of your subwoofer. This will mean running the front right speaker and the front left speaker into those speaker-level terminals in your sub.

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Connecting Your Stereo System to Your Subwoofer

You can boost the performance of your entire sound system if you get it right. Stereo systems also benefit from subwoofers. The improvement goes beyond having deep sounding bass to having a clearer, more sophisticated sound. However, with regards to the stereo system, connecting to the subwoofer works slightly differently.

In this subwoofer connection, there are no bass management features for connecting the receiver – which is the stereo system. The subwoofer high-level inputs come handy for this connection. You will pass your speaker cables between the subwoofer and stereo with their output jacks, just like in a vintage amp without preamp output. This double connection allows the speakers on your subwoofer and stereo to get the full effect of the sound frequencies including the treble, bass, and midrange. the low pass filter of your subwoofer will measure how high the frequency that the sub can reflect. If the speaker drivers are up to 5″, the upper frequency will be within 80Hz but if they are 4″ or less, the upper frequency will be within 100Hz and above.

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What Your High-Level Signals Do to Your Connection

Connecting your sub through its speaker-level input makes your sub see the exact-same signal with other receivers. It’ll actually have no time lag. When you connect speaker output with the RCA jack out, you’ll tend to get some lag as the sub doesn’t exactly sync with the receiver in this connection. This difference may be minimal but if you are familiar with sound output, you’ll notice the difference. Even as a rookie, if you reconnect speaker output on your receiver with the speaker-level on your sub, you’ll be able to tell the difference.

When you connect your subwoofer and receiver to the speakers, they both receive a very similar frequency signal with regards to damping and tonal balance. As a result, the speakers and sub give off the same bass vibe within the same period which ensures there is no lag between the woofers. This phenomenon is important, especially in music studios or devices, since the sound produced needs to synchronize properly. As for home theater subs, the focus is on the deep, heart-thumping bass out.

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