Amp Has Power But No Sound From Speakers or Subwoofer
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An amplifier improves sound quality by driving your speakers and subwoofers with additional power. This means that if your amp experiences any problem, the quality of the sound may considerably deteriorate. One such issue is the common problem is the amp has power but no sound.

In this auricle, we will troubleshoot this issue where your amp has power but no sound from your subwoofer or your amp has power but no sound from your speakers.

The likely cause of this issue is a overheating, overcurrent, overvoltage, a fault in the power system or blown amplifier, a blown output channel or a blown fuse.

Let’s explore in more details. 

How Do Amplifiers Work?

Before we can look at the possible reasons why there is no sound, it is good to know the basic working principle of an amplifier from the input side to the output side.

how do amplifiers work

Once we develop this understanding, we will be in a better position to decide on the best troubleshooting methods to apply. 

An amplifier boosts the sound signal from your music source and supplies that boosted signal to your speakers and subwoofer.  

Audio amplification is described as the process that increases the magnitude of an audio electrical signal. It may sometimes distort the electrical signal on the output of an amplifier due to the magnitude of the signal. 

If we take into consideration an amplifier that is powered by a voltage of let’s say 12 volts as is the case for many amplifiers, the output alternating signal cannot have a voltage greater than that or clipping will occur. 

Amp Has Power But No Sound: Possible Causes And Fixes

If there is no sound at all being produced by an amplifier after it has been powered, then the following are some of the possible causes:

  • Overheating
  • Overcurrent
  • Overvoltage
  • Fault in the power system or blown amplifier

An amplifier that is overheated often has an overvoltage or overcurrent issue and may experience gross distortion of sound.

However, if the problem is not checked in time, the sound may disappear completely.

Additionally, blown amplifiers will stop working instantly as no sound signals will be delivered to the speaker units. However, you may still be able to power on the amplifier even after it’s blown. Let’s discuss this in better detail.

1. Overheating and Overcurrent or Overvoltage

There may be many problems causing your amplifier to overheat. Some of these are:

  • Overpowering the amp
  • Faulty circuitry 
  • Running the amp for a very long time 
  • Overloading the amp
  • Running the amplifier in direct sunlight or near hot surfaces
  • The cooling system of the amp is faulty

When an amp is overheated, it will go into protection mode. However, if the overheat is a result of overcurrent or overvoltage, it is more likely to blow than go into protection.

amp overheating

If you notice that your amp is running very hot and not producing any signal, switch off the power, disconnect the appliances, inspect and resolve the issues causing the overheat.

2. The Power System Is Faulty

One of the problems that is likely to cause the sound signal to disappear from your amp is a fault affecting the power system of the amplifier.

It is either the wiring system is not properly done or the remote is not working properly. If you have the necessary technical skills, check and adjust the wiring so that the amp can be properly powered.

3. A Fault In The Remote Wire

Amplifiers are normally controlled by a remote system. Obviously, if the power button of the remote is off, your speakers and subwoofer will not receive any sound signal from the amp. 

The same thing happens when the remote is on but the wiring system of the remote has a fault. Try to power on the amp manually. 

Also, check the battery layout in the remote system.

The remote will fail to work if the batteries are not properly laid or the wires from the battery unit are rusted or disconnected. 

To correct this problem, remove rust from remote wires, lay the batteries properly, connect broken wires and check that the remote is working properly.

4. A Faulty Power Wire

Power wires deliver current to the amplifier. Power signal wires connect your amp to the speakers or subwoofer. Any of these wires might have burnt out. If for example the gauge of the wire used is incorrect, this could easily happen.

amplifier wiring

This happens because some of the energy used to drive current through the wires is converted to heat.

Very thin wires experience more heating and the wires may burn out if they cannot sustain the current. This may be causal for the sound signals not to reaching the speakers or subwoofer. 

A remedy for this is to ensure that all wire sizes correspond to the allowable quantity of current.

On the other hand, incisions and corrosion may also affect the current flow through the wires. If any of the wires are affected by corrosion or incision, they may not deliver sufficient power to the amp.

The amp may therefore turn on but will not have enough power to drive the subwoofer to produce sound. 

Switch off the mains when handling power cables and repair or replace damaged wires. You can use an multimeter to check the cables for the presence of voltage and replace faulty wires. 

5. Impedance Mismatching 

Amplifiers are designed to handle speakers and subs of specific impedance levels or ranges.

There might be a challenge of unmatched impedance between the powered speaker or sub and the powered amplifier, if either the speaker/sub impedance is too high or too low to be supported by the amp.

If your subwoofer draws too much current from the amplifier, the system may be overpowered and jump into protect mode. However, if the sub draws too little current due to a massive impedance difference, you will not hear any sound either. 

If your amp is rated 4-ohms, the subwoofer should also be 4-ohms rated, and so on. Replace mismatched subwoofers or amplifiers depending on which component is easily accessible, or cheaper to replace.

Check if the protect mode lights are still on. Also, if the lights are on but the amp is properly matched with the subwoofer, the subwoofer itself, the subwoofer cables or even the other components connected to the amp could be faulty. 

6. Polarity Mismatch In The Speaker Connection

Another possible reason why there is no sound signal from a powered amplifier might be misalignment of the polarities in the various ports.

If the polarities are interchanged for the case of speaker wires connecting the amplifier, we expect no sound to be produced.

You should therefore check the wire connections to ensure they are connected in the right way.

7. Blown Fuse

Subwoofers have built-in fuses or circuit breakers for self-protection against overcurrent.  if for example there was a current urge or short circuit, the subwoofer will not power up.

blown amplifier fuse

If you have a tripped circuit breakers, this is likely the issue. Before replacing a fuse however, you should find the faulty that caused it and rectify that first. 

Conclusion

As observed, several problems can be attributed to the lack of sound even though your amp is powered. It is therefore recommended that you troubleshoot your different devices, connections and components before connecting and trying to run them.