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My Amp Has Power But No Sound To Sub: Sure Fixes In 9 Steps

Last Updated on: May 16, 2022

Is your amplifier turned on, but no sound is coming from the car stereo? Well, you’re not alone; most drivers have experienced this irritating situation at some point. Unfortunately, most of us mistake this for a blown subwoofer or alternator whine and end up replacing the speakers. 

But…

The main difference between a blown speaker and this problem is that with the previous, you do get low sound. Without wasting more time, let’s find out how we can fix this issue.

How Does a Car Amplifier Work?

Before we find out why my car amp turns on but no sound from the sound system, we need to understand how the amp functions from the input to the output side. Knowing how it works can help us decide the best troubleshooting method to use and repair the sub/amp and the rear speaker.

Generally, the car amp boosts the sound signal before supplying it to the sub and speakers through a wire.

My Amp Has Power But No Sound to Sub

As aforementioned, most drivers’ mistake amp has power but no sound from subwoofer with a blown or faulty subwoofer, with loose wire, which is not the case. The subwoofer may not be the cause of the problem because even when blown, it does produce sound. So if you want to know how to troubleshoot the amp has power but no sound problem, please read on.

1. Check Amplifier’s Power

It’s a known fact that the amplifier has a power supply unit that can function even when it’s not receiving the required power. And when this happens, your amplifier may appear to be working perfectly, but the speakers won’t produce any sound. Remember, most amplifiers power at between 6-volts and 10-volts. Plus, with suboptimal voltage, your amplifier may not be able to amplify the signal and transfer it to the car stereo. 

The first thing you should do is measure the voltage of its positive and negative terminal to ensure that this is not the cause of the amp turns on but no sound.

A perfectly working amp should give a voltage reading of between 12v and 14v. If it gives a lower power reading on the voltmeter, then you should check the grounding bolt, battery connection, and the ground wire and power wire at its fuse block. 

2. You Can Even Confirm if the Factory Amp Has a Blown Fuse

A huge percentage of the car amps come with a built-in fuse switch that you have to inspect when troubleshooting this problem. If the amp turns on but no sound from speakers and the fuse is not blown then it will give a reading of about 0-ohms on your multi-meter.

Make sure you inspect the wire and its connection to the subwoofer and cd player. Double-check always on your amp since it could be also suffering from bad ground on amp symptoms. In this case, check the grounding location of your wire or cable.

3. Check the Amplifier’s Input Cable

If your amplifier is working perfectly, but the speakers are still producing no sound, then you should examine its wire linking it to the head unit. Examine the RCA cables connecting the amp to the head unit, and if the head unit has several RCA outputs, you should check them as well. 

If replacing the RCA cable doesn’t work, then the issue may be with the head unit and not the amplifier or harness linking the audio system together.

To confirm this, you should look for 3.5mm-to-RCA wires and connect them to your phone and the car’s amplifier and play something. If the speakers come alive, then the sub output and amp are fine, and your car’s head unit needs to be repaired. The same procedure could be used when your car stereo won’t turn on but it has power.

Car amplifier with attached input cables
Car Amplifier with Input Cables Attached

4. Check the Amplifier’s Output

After examining the input panel and confirming that it’s working properly, you can proceed to the output panel. Make sure you know how to tune a monoblock car amp to avoid busting speakers or damaging your car amplifier.

To confirm if the output is working properly, you need another speaker or subwoofer.

Start by hooking up the speaker to the amplifier’s channels one by one. Doing this will help you determine if the problem is with your amplifier’s output or the subwoofer.

5. Check if the Speakers Are Short-Circuited

The above tests will help you determine if the amplifier and the head unit are the issues. If the above tests confirm that the head unit and amplifier are fine, then you should proceed and examine the power wire. Finally, you can confirm if the subwoofer’s fuse has short-circuited. 

Short-circuiting is a key problem for speakers and subwoofers. Unfortunately, most folks don’t find out about short-circuiting immediately; they only discover this after finding out that the amp turns on but no sound from subs.

Therefore, if there is a metallic thing connecting the negative and positive poles at the sub’s terminals or cone, then it will short-circuit.

You should examine the subwoofers with the stereo and amplifier systems if the amp powers on but no sound is produced. If it’s still producing no sound, then it means that the wire is burned and the amp is not transmitting any signal. Make sure you inspect the remote wire before reassembling the car audio system.

6. Inspect the Sub’s Electromagnetic Coil and Cone Seal

If the amp turns on but no sound, then you should proceed with a detailed examination of the subwoofer’s cone seal and voice coil. Therefore, you will have to open your speakers and examine the internal components, and this includes the speaker wire. Start by inspecting the sub’s cone and how it’s sealed to its enclosure.

The cone is one of the most crucial components of the sub that’s responsible for producing the sound by moving forward and backwards while pulling and pushing air. If its seal breaks or loosens, then it can’t move or produce sound.

If the amp turns on but no sound from car audio, then you should also check if the electromagnetic coil is out of place or has burnt spots.

If it’s out of place, then it won’t be able to produce powerful electromagnetic fields to interact with the magnets required for producing a deep-base sound. A loose amp wire can also prevent the car speakers or subwoofer from producing sound.

7. Check the Subwoofer’s Settings

A huge percentage of the aftermarket car stereos come with a separate woofer control in the settings that can be switched off. Therefore, you should confirm if the speaker level is over 0 and the sound output or subwoofer output is switched on.

8. Make Sure Your Amplifier Is Mounted on a Non-conductive Surface

Make sure that no part of your amp is connected to any metallic part of the vehicle.

If any part of the amplifier is attached to a metal surface, then it can result in many problems like signal clipping, or it may switch to protection mode.

9. Polarity Misalignment

Another reason why the speaker is not producing sound is due to the misalignment of the polarities in some ports. If the polarities of the amp and speaker are interchanged, you will not hear any sound. If the amp turns on but no sound from speakers, then you should ensure that the power cable is connected correctly.

One way of avoiding polarity misalignment is to turn on amp without remote wire. You could easily do this either by following instructional videos on the internet or by requesting assistance from a car audio electrician.


Frequently Asked Questions

Can Overheating of the Amp Prevent Your Sub From Producing Sound?

Yes, when the amplifier overheats, it switches to protection mode resulting in the production of no sound. The amp can overheat if there is faulty circuitry, overloading of the amplifier, or if its cooling system malfunctions. Running the amp near a hot surface or in direct sunlight can also cause this problem.

But if overheating is caused by overvoltage or overcurrent, then it has a high likelihood of blowing instead of switching to protection mode.

Can Impedance Mismatch Force the Speakers to Produce No Sound?

Generally, amps are designed to handle subs of certain impedance ranges. Therefore, if your amp or speaker’s impedance is too high, then it may switch to protection mode and produce no sound. 

If the sub draws too much power from the amp, then the system may switch to protection mode. But if the amp has more impedance than the speaker, the sub may end up pulling very low current from the amp, and you may end up hearing no sound.


Conclusion

We all love listening to our favorite songs when driving; unfortunately, our vehicle’s stereo is prone to malfunctioning. If the amp turns on but no sound from the speakers, then your system may be suffering from a wide range of issues.

Therefore, before resorting to buying a new amplifier or sub, you should troubleshoot the problem first. But if the problem still persists, then you may have to replace the factory speakers with a 2-ohm sub or purchase a high-quality amp.

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