9 Reasons Why Car Amp Getting Hot + Tips to Prevent It

Why is My Car Amp Getting Hot?

One of the easiest ways to improve the sound in your vehicle is upgrading to an aftermarket amplifier.

Not only do they bring detail and clarity into the sound, but they also reduce distortion at higher volume levels and fine-tune your system’s performance.

The only caveat is that you should keep them cool to get the most out of them.

Overheating is a significant concern in car amplifiers as it can reduce their efficiency and shorten their lifespan in the long run.

Why is My Car Amp Getting Hot

Based on my experience, the most common reasons for amp overheating include poor installation, bad airflow, load mismatch, incorrect gain settings, or a poor-quality amp.

In this post, we’ll discuss these issues in great detail.

How to Prevent Car Amplifier From Overheating

1. Inadequate Ventilation

The first and most common reason for amp overheating is inadequate ventilation.

Inadequate Ventilation

People install their amps in random places and orientations (upside down, under the seats, etc.) to get them out of sight. In doing so, they independently cause the amps to overheat as they don’t have any breathing space in those places.

2. Impedance Mismatch

Every amplifier has a specific power handling capability at 4 Ohms, 2 Ohms, or 1 Ohm.

So, if your subwoofer has a 2 Ohm impedance, but the amp can only work in 4 Ohm mode, the latter will start to overheat.

To avoid this, always go for the amp that can provide power to your speakers/sub in their specific impedance range.

3. Blown Subwoofer

Blown Subwoofer

A blown subwoofer is another indirect reason why car amplifiers can overheat. These subwoofers can have their voice coil shorted, which can cause the impedance to drop significantly.

This drop creates a mismatch which causes the amplifier to overheat.

4. Incorrect Wire Gauge

Incorrect Wire Gauge

The power and ground wires of the car amplifier come with different thicknesses/gauges that determine how much current can pass through them.

Picking smaller-gauge wires for the amplifier will cause the voltage to drop because of increased resistance. Due to this voltage drop, the amp has to work harder to draw power, producing extra heat.

5. Poor Amp Grounding

Poor Amp Grounding

weak or loose amplifier ground connection can cause resistance in the ground wire, eventually leading to overheating (just like an incorrect gauge). When choosing a ground spot for the amp, ensure it’s a bare metal surface with no paint or rust.

6. Loose/Corroded Battery Connections

Corroded Battery Connections

You should also check the power and ground wire connections on battery terminals. These connections can get loose or corroded over time and cause the amplifier to overheat.

If the connections have no issue, I recommend checking the wires themselves. These wires can often get damaged or frayed, leading to increased resistance in them and amp overheating.

7. High Ambient Temperature

The amplifier can sometimes overheat simply due to higher ambient temperature. Usually, an amp relies on air from the outside environment to cool itself down. But if the outside air is hot too, the heat won’t dissipate.

If you’re getting overheating issues only after parking your vehicle, a higher ambient temperature can be a possible reason.

8. Incorrect Amp gain settings

Incorrect Amp gain settings

The amplifier gain settings determine how much amplification should be done on the audio signal. But most people mistakenly think of it like the volume knob and set it to the highest level. It causes the amp to overheat and also introduces distortion in the sound.

Here’s how you can correctly set the amplifier gain using a multimeter.

  • Turn up the volume to 75%.
  •  Go to EQ settings and turn off any EQ/bass enabled.
  •  Find your amplifier’s voltage using this formula: V = √(RMSxImpedance). For example, if the amplifier has a rated RMS value of 100 watts at 4 Ohms, the voltage will be V = √(100 watts x 4 ohms) = √400 = 20 volts.
  •  Now set your multimeter to AC voltage mode.
  • Connect its leads to the amplifier’s positive and negative speaker outputs. Polarity matters here. Therefore, the negative lead will be connected to the negative output. And the positive lead to the positive output.
  •  Play the music and continue tweaking the amp gain knob until you get the 20V value on the multimeter.

9. Faulty Battery/Alternator

In some rare cases, a faulty battery or alternator can malfunction and cause the voltage to drop. And that voltage drop can lead to overheating.

Therefore, you should test both components with a multimeter and confirm that they work fine.


Overheating reduces the efficiency as well as the lifespan of a car amplifier. Therefore, it should be avoided at all costs.

You can find and fix the problem’s actual cause by following the above steps.

If not, I suggest installing a new car amplifier, as there’s a high chance that your current one is malfunctioning due to an internal failure. And that internal failure is causing it to produce more heat than usual.

Frequently Asked Questions

Is It Normal For A Car Amplifier To Get Hot?

It’s normal for car amps to produce heat as a byproduct, but it shouldn’t be more than what the manufacturer specified in the owner’s manual.

How Do I Stop My Car Amp From Getting Hot?

You can stop the car amp from overheating by providing necessary ventilation, adjusting the amp gain correctly, avoiding the top-volume levels, and matching the amp with the speaker impedance.

Why Does My Car Amp Smell Like It’s Burning?

If your amp smells like it’s burning, it either indicates that it’s covered in dust, which is burning due to overheating; or that its internal components are malfunctioning and producing this smell due to overheating.

How Hot Should A Car Amp Get?

Most high-quality car amps can go up to 85°C before going into protect mode or shutting off. Generally, the amp is fine unless it’s too hot to touch.

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I'm Miles Walker and I'm the founder of autoaudiolab.com I've been in the car audio industry for over 20 years and have a wealth of knowledge to offer on all things related to car audio. I graduated from UC Berkeley with an electrical engineering degree, so you can rely on me for top-notch expertise and advice when it comes to upgrading your sound system.

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