Can a Headphone Amp Power Speakers? All You Need to Know

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Speakers and amplifiers go hand in hand. Speakers produce sound, and amplifiers make speakers sound. In short, all speakers depend on amplifiers in order to work.

With the craze for acquisition and experimentation of/with new gadgets and devices, some musical enthusiasts have been asking, “Can Headphone amplifiers be used to power speakers?”

No, Headphone amplifiers cannot power speakers. Speakers require a relatively large amount of power to drive them, but headphone amplifiers generate significantly less than 1 watt of power. This is not enough to drive speakers.

As you may already know, speakers require a power amplifier to drive them. Most consumer speakers these days usually have a power amp built into them. However, for regular passive speakers, you need to purchase a standalone power amp. 

But how does a power amplifier differ from a headphone amp? Well, that’s what we’re going to take a look at next. And then I’ll follow it up with all of the reasons why headphone amps cannot power speakers.

Headphone Amplifiers Vs Power Amplifiers

In terms of functionality, headphone amplifiers and power amplifiers operate based on the same principle. Their basic design can be similar as well, but honestly, the only thing headphone amplifiers and power amplifiers in common are that they both amplify audio signals and drive voice coils to produce sound. However, here is what makes them different.

Headphone amps, just as the name depicts, are made to drive headphones. In fact, every device that allows you to plug in a headphone has a built-in headphone amp. However, more often than not, these built-in headphone amps are not powerful enough, especially for higher-end headphones. That was why external headphone amps were made. Here is how they work. 

Every headphone has an important known as the voice coil. Although there is more is to it, you can think of a voice coil as a copper wire which has been coiled. Keep this in mind.

Voice coils are an essential component in a headphone because it causes it to make a sound. But how does it do that? 

Voice coils receive audio signals from whatever device the headphone is connected to, in the form of electric currents. When this current (or audio signal) passes through the voice coil, it instantly turns it into an electromagnet. I’m sure you’re familiar with this concept if you remember your elementary or high school physics.

Once the voice coil becomes an electromagnet, it begins to repel and attract the headphones’ permanent magnets. This causes the headphone drivers to move back and forth to produce sounds. If you’ve read our article on how bass damage headphones, I’m sure you’re familiar with how voice coils work.

What a headphone amp essentially does is to boost or “amplify” any audio signal before it gets sent to the headphones or voice coil. The power (or electric current) that will be sent to the headphone will be much higher than without it. This will result in increased volume, a fuller sound, and sometimes improves the clarity of the signal.

Now let’s talk about speakers and power amplifiers briefly.

Speakers and headphones are very similar when it comes to how they work. Speakers also have a voice coil which causes them to produce sound when they receive an audio signal (or electric current) from an amplifier.

Speakers, however, are designed to play much louder than headphones. All of the components inside a speaker are much bigger compared to a headphone. For this reason, they require a lot of power to function—way more power than is required by headphones.

Power amplifiers are designed to supply the needed power to speakers for them to work efficiently. 

In essence, all I’m trying to say is that speakers require a much higher power to work than headphones. Headphone amplifiers are designed to supply headphones which require much less power than speakers. Power amplifiers are designed to supply speakers with high enough power to drive them.

Here is the simplest difference between a headphone amp and a power amp. But for my audience that is a bit technical and knows a little about electricity here is the difference between a headphone amp and a power amp.

Headphone Amplifier Vs Power Amplifier: Impedance

The big difference is that; they are designed to handle different resistance loads. Power amplifiers are designed to handle a load impedance of 4 to16 ohms. On the other hand, headphone amps have been designed to handle load impedance in the range of 16 to 600 ohms.

As I stated earlier, loads with low impedances require a lot of power to drive them. This means headphone amplifiers are designed for loads that do not require lots of power.

Headphone Amplifier Vs Power Amplifier: Power, Current and Voltage

The difference in impedances between headphone amplifiers and power amplifiers affects every other electrical property associated with these amplifiers. Hence headphone and power amplifiers differ in terms of power, current and voltage demands as well.

Electric Property  Headphone Amplifiers  Power Amplifiers
PowerThey are built to supply very little power to drive headphones. About 1000 times less than that needed by power amplifiers.They need high power to drive loudspeakers.
CurrentIt allows/ needs very little current to functionIt needs high amount of current in order to operate
VoltageIt can’t supply enough voltage to drive loudspeakersIt is able to supply enough voltage to drive loudspeakers.

Why Headphone Amps Cannot Power Speakers

As mentioned earlier, theoretically, headphone amplifiers and power amplifiers do not differ. They work the same way. But headphone amps simply cannot supply enough power to speakers to drive them. That’s the main reason why headphone amps cannot power speakers. However, there are more reasons why they are not ideal for speakers. 

Here are a couple more reasons not to power speakers with headphone amps

1. No Speaker Connectors on Headphone Amps

One of the problems with headphone amplifiers is that they don’t even have slots where connectors for speaker cables can be fixed. For you to own a headphone amplifier that has a slot where speaker cables can be connected, you would need to DIY. 

Honestly, the time and effort it will take to build a headphone amplifier which takes speaker cables would be best spent acquiring a power amplifier.

2. Low Output Voltage

Headphone amplifiers are usually rated by how much output voltage they can deliver.

Headphone amplifiers are designed to deal with very small voltage signals, sometimes measuring a few nanovolts. Unfortunately, these voltages are not strong enough to drive speakers.

3. High Output Impedance of Headphone Amps will Alter Frequency Response

Many headphone amplifiers have an output impedance in the range of 0.5 – 50 Ohms. Speakers, on the other hand, have an input impedance of 4 to 12 Ohms.

Ideally, an amplifier’s output impedance must be eight times less than the speaker’s input impedance. For instance, if you’re using a speaker with an input impedance of 8 ohms, the amplifier’s output impedance must be 1 Ohm or less.

If that’s not the case, it will affect the frequency response of the audio signal being sent to the headphones. Simply put, the headphone amp won’t send accurate audio to the speaker, and this will affect the sound quality.

Most headphone amps have output impedance usually higher or than a speaker’s input impedance. So even if the headphone amp is able to supply the required power to the speakers, they won’t sound great.

4. Headphone Amplifier May Damage Due to Heat

Theoretically, there are high expectations that some headphone amplifiers can be used to drive loudspeakers successfully. Even if this is achieved, the headphone amplifier will be forced to overwork itself to meet the loudspeaker’s power requirement. This will cause the amplifier to overheat because it is not designed to power such speakers.

How to Properly Power a Speaker

At this point, I’m sure we’ve established the fact that headphone amps cannot power a speaker. The only way to drive a speaker is with a power amplifier. 

You need to find the right power amplifier for your speakers in order for them to work efficiently. But how do you find the right power amp for your speakers? This is where speaker to amp matching comes in.

Speaker to amp matching is a process for finding the amplifier with the power rating suitable for your speakers. UniqueSquared made an excellent video explaining how this is done. If you have plans of purchasing an amp for your speaker, you definitely need to check it out.

Conclusion

In summary, headphone amps cannot deliver large amounts of power required by a speaker to work. This means they can’t power or drive speakers.

Ultimately, when it comes to loudspeakers and amplifiers, it is important to take note of their maximum handling capabilities. It is best to get an amplifier that is slightly more powerful than the ratings of your speaker. This will help ensure that only clean and undistorted power gets to your loudspeakers.