Can Amplifiers Damage Headphones? And How to Prevent It

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As an avid member of many audiophiles and general audio forums, one question that I see many newbies ask is, can amplifiers damage headphones? Although I thought this question had an obvious answer, it seems it’s not as obvious as one may think. So I decided to write a full article about it. After a few hours of research, here is what I found.

Can amplifiers damage headphones? In short, yes. Amplifiers can damage headphones. When you plug headphones in a too powerful amplifier and crank up the amplifier’s volume, the amp will deliver much higher power to the headphones than it can handle. And that can damage the headphones. Also, plugging your headphones in a speaker amplifier’s output will easily break it.

Let’s take a closer look at the instances where an amplifier can break a headphone and how to prevent them from ever happening.

How Amplifiers can Damage Headphones

Here are the ways amplifiers can damage headphones.

1. Using Headphones with an Overpowered Amplifier

As you may already know, there are hundreds of headphones available today. And one of the few things that differentiate headphones is their impedance

A headphone’s impedance is it’s resistance to the electric current being transmitted through it. It is measured in ohms and represented by the greek alphabet omega (Ω)

Headphones’ impedance is very important because they determine the amount of power required to drive them (or play audio through them). 

Small earphones such as your iPhone’s earbuds or anything similar usually have low impedance. These earbuds usually have impedance between 8ohms to 60ohms. In the world of headphone impedances, these are considered as low impedance. 

For this reason, these headphones don’t need much power to work, which is why you don’t need a dedicated headphone amplifier to drive these small earphones. Your phone or computer’s built-in amplifier can drive these headphones without any issues.

There are many other excellent headphones such as the Philips SHP9500 Headphones (on Amazon) or the Audio Technica ATH-M50x Headphones (also on Amazon) that are low impedance headphones, so they don’t require much power to work.

And then there are high impedance headphones. These are essentially headphones that need more power in order to work efficiently. When you plug a high impedance headphone into a low power amplifier such as your phone or computer’s headphone jack, the audio output from the headphones will be very low, if audible at all.

For this reason, high impedance headphones require headphone amps to drive them efficiently. The power required by the headphones depends on the impedance on the impedance on the headphone.

The higher the headphone impedance, the higher the power it requires to drive them at a certain loudness.

There are many different headphone amplifiers available today with different power ratings to cater for various headphones. So it’s important to find the right headphone amp with an excellent power rating for your headphones. 

Here is where most people get it wrong. Many people end up buying amplifiers that are either too powerful (or overpowered) or not powerful enough (underpowered). If an amplifier is too powerful for the headphone, it can easily damage it. Here is how.

As you increase the amplifiers’ volume, essentially, what you are doing is sending more power to the headphones. Feeding more power to the headphones is what causes them to play louder. An overpowered amp will send a high power that exceeds the headphone’s maximum input power limit. And this will easily break the headphones.

Let’s say you own a pair of headphones that has a maximum input power of 500mW, and you use it with a headphone amp with a maximum power output of 2W. Increasing the amplifier halfway volume will send a power of 1W to the headphone, which is twice the headphone’s maximum input power. And that will break the headphones in no time.

If your headphones don’t stop working after receiving more power than it can handle, the sound quality will reduce drastically. You may either hear a lot of crackles while you use it, or it will produce a distorted sound. 

This is why you need to always find the right headphone amp, which will be safe to use with your headphones. I’ll show you how to do that later in this article. So let’s continue.

2. Plugging Headphones in Speaker Amplifier’s Output

Another mistake that will instantly damage your headphones is when you plug in a power amplifier’s output.

Some people have the perception that the output of a power amplifier sounds much better than regular headphone amps. Many ends up finding out the hard way connecting the power amplifier’s output to headphones will quickly damage the headphones. I still cringe when I hear people consider doing this. 

Here is why using a power amplifier with a headphone is harmful to the headphones.

Headphones are devices that require much less power for them to work efficiently. That’s because the size of headphone drivers is much smaller compared to speaker drivers. Also, since headphones are placed directly on the ear, they don’t need to play loud enough to be heard. For this reason, headphone drivers usually have maximum input power in milliwatts (mW)

Speakers, on the other hand, require a lot more power to work efficiently. They have much bigger drivers that need more power to drive them. So speakers have much higher power ratings than headphones, and they are usually in Watts (W)

Because speakers require more power to work, speaker power amplifiers are designed to deliver a much higher power — way more than what headphone amps can deliver.

So if you plug headphones in the speaker output of power amplifiers, the amp will deliver way more power to the headphones than it can possibly handle, and that will instantly fry the headphones.

You’ll be lucky if you run such a high current from the power amplifier through your headphones, and it doesn’t break.

How to Prevent Amplifier from Damaging Headphones

I have three tips on how to prevent amplifiers from ever damaging your headphones. Here goes:

1. Find the right amplifier for your headphones

As I mentioned earlier, quite a number of people make a mistake and buy headphone amplifiers that are just too powerful for their headphones. But if you want to make sure you don’t put your headphones and your ears in danger, here are the tips you need to follow to find the best headphone amp for your headphones.

Firstly, you need to know your headphone’s impedance rating. The impedance rating of headphones can be found online, on product pages, spec sheets, or in the user manual. Look it up online to find them.

Secondly, you need to know your headphone’s efficiency or sensitivity rating. This can also be found on product pages of the headphones, spec sheet, or user manual.

Once you have these two values, you need to calculate the amount of power (in milliwatts) required to drive these headphones at a certain volume. You can use an online calculator such as the Digizoid Headphone Power Calculator to find this value.

Once you obtain the headphone power required, it’s time to go shopping for a headphone amp. You need to find a headphone amp that has power output exactly the same or close to the headphone’s power requirement. 

You can find the headphone amp’s power output on their product pages, spec sheet, or user manual, which can be found online. As a rule of thumb, find a headphone amp with a slightly higher power output than the calculated headphone power requirement.

Another important piece of information you want to know about the headphone amp output impedance. I explained why, in detail, in this article. You should definitely check it out.

One headphone amp that is known to work extremely well with many headphones is the Schiit Modi 3 DAC/Amp (on Amazon). You can save yourself the calculation and go for this one if you need something that will work great right off the bat. 

2. Never plug your headphones in speaker output

I think the heading says it all, but I’ll repeat it again. Do NOT ever plug your headphones in a power amplifier’s speaker output unless you want to risk damaging it permanently.

As we have already discussed, the power delivered by a power amplifier to speakers is too high for headphones to handle. That high power from the speaker output will fry the electronic components in the headphones in no time.

Many DACs, amplifiers, and audio interfaces out there have both speaker output and headphone output. A very popular audio interface that has both is the Focusrite Scarlett 2i2 (on Amazon)

At the back of this unit or any other unit, you’ll find ports labeled “Main Outputs” or “Speaker Output.” These outputs are meant for speakers only, and you should never connect your headphones to these ports.

On the front panel is where you will usually find another port labeled “Phones” or “Headphones” or simply have a headphone icon as the label. This is the only port you can safely connect your headphones to. Headphone ports are designed to send milliwatts of power to your headphones, and it’s highly unlikely to damage it compared to speaker outputs.

Conclusion

In summary, amplifiers can damage headphones when they supply a much higher power than the headphone’s maximum input power. This can instantly damage the headphones, and it might not work again, or it will result in poor sound quality from the headphones.

Besides amplifiers, many other factors can damage a headphone. I talked about some of these factors in this article. Feel free to check it out.