7 Reasons Why Your Subwoofer Keeps Blowing Fuse – How to Fix

What Is a Fuse?

A fuse is an electrical device that acts as a safeguard against excessive currents in an electrical circuit. It breaks the circuit when too much current passes through, thereby preventing damage to other components in the system. This property makes it an essential part of any car audio system, as it can help protect the wiring, speakers, and amplifier from damage due to electrical power surges.

Why Do My Subs Keep Blowing Fuses?

Subwoofer systems are a great way to add bass and depth to your sound. However, if you’ve been experiencing persistent fuse-blowing with your subwoofers, there is likely an underlying cause for it. The most common reasons are given below:

• Faulty amplifier
• Overload circuitry
• Loose wiring
• Mismatched amplifier for sub
• Short IC in amp
• Using wrong-sized fuse
• Faulty power supply

If you’re experiencing fuse-blowing, the first step is ensuring that you have securely connected the sound system’s components and that no wiring has been damaged.

1. Faulty Amplifier:

Faulty amps can blow a fuse if they are not functioning correctly and some parts become shorted out. A short circuit ⁽¹⁾ is when a current flows between two points in an electrical device that should not usually be attached or carry any electricity. When this happens, the voltage increases to unsafe levels and will often cause a fuse to blow. It is important to remember that it can only protect the system from too much current and not from poor-quality parts or design. If the amplifier cannot correctly regulate the voltage, it could cause it to blow. There are several ways in which faulty amplifiers can blow it, including:

• Overheating: A malfunctioned cooling system cause amplifier to overheat, resulting in a blown fuse.
• Poorly designed circuitry: It causes a voltage surge.
• Using too much power: Small-sized fuse can’t handle high-power input.
• Faulty components: A faulty capacitor or resistor can blow a fuse.

2. Overload Circuitry:

Overload circuitry monitors the amount of electricity flowing into a device; when that amount exceeds the safe level for a particular device, it triggers it to blow. When you drive too much power through an electrical line, it opens the circuit and breaks the flow of current before it causes damage. This process can also be triggered if a device draws more power than it is rated for. In either case, when the circuit overloads, a large amount of heat builds up quickly, causing the fuse’s internal material to melt away to open the circuit.

3. Loose Wiring:

One of the reasons why your subwoofer keeps blowing a fuse is loose wiring, resulting in no sound coming from the sub or low volume. When wires become loose due to vibrations from bumpy roads or other movements, they can create an electrical arc that generates heat. This heat can overload the circuit board, resulting in a blown fuse.

4. Mismatched Amplifier For Subwoofer:

Excessively pushing a sub with an amplifier unsuited for its power rating can result in its blowing. This happens because the amplifier cannot handle the high current draw from the subwoofer and cannot control it efficiently, causing power spikes and surges, which overload it. Poorly matched amplifiers will also cause distortion, leading to further strain on the fuse.

5. Short IC in Amp:

When an IC (Integrated Circuit) ⁽²⁾ in an amp shorts out, it can cause the fuse to blow. This occurs because a short circuit increases the current flowing through the amp, which is greater than what the fuse can handle. If this happens, the circuit’s internal resistance decreases, and a large amount of current is drawn from the electrical supply. As the current rises, it eventually surpasses the fuse’s limit, causing it to blow.

6. Using Wrong-Sized Fuse:

Using the incorrect size fuse on a subwoofer system can cause it to blow. However, a larger-sized fuse will not be able to react quickly enough when there is an over-current condition, allowing too much current to pass through before it has a chance to disconnect. On the other hand, if it is too small for the circuit, it will blow too quickly because of not having enough capacity to allow the current to pass through the circuit. In either case, the fuse will eventually fail, making it necessary to replace it.

7. Faulty Power Supply:

The supply converts the AC voltage into DC voltage, providing the necessary current to power the amplifier and drive the speaker. If it has defects, such as a surge of electricity or a short circuit, this can cause too much current to flow through it, resulting in its blowing. Additionally, if it is not functioning correctly, this can also cause the fuse to blow. In either case, it is essential to have the supply inspected and repaired before attempting to use the subwoofer again to avoid blowing a fuse again.

Quick Fixes?

1. Repair your Amplifier:

As discussed above, the amplifier is responsible for boosting the signal from the source (the audio player or receiver) and then sending it to the subwoofer. If you notice any issues, you can quickly solve the problem by having your amplifier professionally repaired. A professional repair will ensure that the amplifier is working correctly and can help prevent a blown fuse in the future. Furthermore, having a technician perform regular maintenance on your amp can help extend your subwoofer’s lifespan.

2. Fix the Loosen Wires:

It’s essential to ensure that all the wiring is securely attached and adequately insulated. Ensure that you connect each wire correctly to its terminal and that there are no gaps or breaks in the insulation. If you aren’t familiar with car audio wiring, take your car to a professional who can check it and ensure it is properly connected.

3. Match Your Subwoofer and Amplifier:

You must match both devices’ power to ensure that your amplifier and subwoofer are not overloaded. This means that the output of your amplifier should match or be slightly higher than the power handling capacity of your subwoofer. Doing this can prevent overload and ensure it will not blow.

4. Replace Your Short IC:

If you notice your amplifier has a short IC, you need to replace it with the right one. It will prevent the subwoofer from blowing a fuse. Replacing the IC will help restore the regular operation of the device, preventing further damage to other parts. Replacing the faulty IC can also improve efficiency, eliminating unnecessary load on other parts. When replacing an IC, it’s essential to use the same model as the original to ensure optimal performance.

5. Use Right-Sized Fuse:

You should choose the correct fuse size based on the subwoofer’s current draw and impedance. The current draw is usually stated in amps (A) or milliamps (mA), and the impedance rating is generally expressed in Ohms (Ω). The ideal size fuse should be the total of both these values. For example, if a sub has a 5A current draw and an 8 Ω impedance, then the correct size fuse to prevent it from blowing would be 13 A. It is important to note that it should always be slightly larger than the total of both values. By choosing a fuse with the correct rating, you can ensure that your subwoofer and amp are adequately protected from an overload.

6. Fix or Replace the Faulty Power Supply:

You can help prevent your subwoofer from blowing a fuse by ensuring that your supply is working correctly. If your supply isn’t working, it may be necessary to replace or repair it to ensure that your stereo is functioning correctly and safely.