Active Speaker Humming: Causes and How to Fix Each One
Active speaker humming can come from a faulty volume pot, a bad capacitor, a damaged final transistor or the input. Learn how to find and fix the cause.
Active speakers have become one of the most sought-after pieces of audio gear. Listening to music or watching movies is better with an active speaker. But what if the speaker suddenly starts to hum? No need to panic. Here are the causes of a humming active speaker and how to fix them.
Causes of Hum in an Active Speaker and How to Fix Them
- Faulty Volume Control
One cause of speaker hum is a damaged potentiometer (pot). The pot controls the volume, and if it gets dirty or old, it makes the active speaker hum. Try turning the speaker on and then turning the volume from the lowest setting to the highest.
If the hum disappears at a certain point as you turn it, the problem is most likely dirt. You can spray it with contact cleaner. If you don't have any, thinner or alcohol will do. This step can fix a humming active speaker. If it doesn't work, just replace the pot with a new one.
- Problem With the Power Supply Capacitor
The power supply in an active speaker is very important because it supplies voltage to the loudspeaker diaphragm. Its components are electrolytic capacitors (elco), diodes, and a transformer. If a capacitor has a problem, it causes a humming sound. If you find a bulging capacitor, it must be replaced. The sign is that you can hear the music but there is still a hum.
- Damaged Final Transistor
One cause of hum in an active speaker is a damaged transistor. On the market, amplification usually uses transistors in a pre-amp stage, a driver stage, and a final stage. The final stage works hard to get full voltage, so a cooling plate (heat sink) is needed to minimize overheating.
Because it works so hard, this part often fails from overheating. When it fails, the active speaker produces a hum. When you play music, all you hear is humming. You need to replace it right away, because if you don't, the loudspeaker itself can be damaged too.
- Problem With the Signal Input
The signal input can also have problems that make an active speaker hum. First check the 3.5 mm RCA input, if you use it. This is actually the easiest fix. If the cable is plugged in and the speaker hums, just replace it with a new one of the same type.
The best way to deal with a humming speaker is to run checks first. That way you know where the cause is and can take action. Replacing the damaged part is considered the most effective fix. Just make sure you choose quality components so they last.
