Audio Interface vs Headphone Amp: Is It a Same?

If you’ve been researching headphones, you’ve no doubt come across headphone amps.  But aren’t they already built into audio interfaces? In this article, I’ll explain what each is and when you might need them.

Many audio interfaces function as headphone amps. However, headphone amps cannot serve as an audio interface. Instead, headphone amps are most often used when you want to use more than one pair of headphones or when you need more power/volume.

Most home studio producers will find an audio interface more than capable of handling their audio playback needs. This way, you can save money on equipment and invest it somewhere more important.

Reasons To Pick An Audio Interface

Let’s talk about why and when you might prefer to use an audio interface. These reasons are generally more significant for music producers than for an average music listener.

• Conversion Quality

An audio interface provides a built-in digital-to-audio converter or DAC, which a headphone amp doesn’t offer. It is evident by the fact that an audio interface connects to your computer via a data connection like USB or Thunderbolt. So, using an audio interface with your phone or computer bypasses its internal converter with a potentially better DAC.

Despite having better amplification components in a headphone amp, a low-quality DAC on your computer’s motherboard or phone can nullify the hardware’s quality. It results in subpar quality compared to the sound produced by an audio interface.

For example, most phones provide a 16-bit 44.1 kHz sample rate audio. However, an audio interface provides a higher bit depth and sample rate in almost every case.

• Recording

If you are a music producer, you will undoubtedly want to record audio as much as you listen. So, you will require an audio interface for recording audio. Furthermore, an audio interface provides preamps, phantom power, direct monitoring, etc., which aren’t available in a headphone amp.

So, if you are going to be making music on a computer, avoiding an audio interface isn’t an option. The same reasoning goes for streamers, YouTubers, podcasters, and live performers who wish to record audio using their phone or computer.

• Speakers

If you want to listen to your DAW on speakers as well as headphones, an audio interface is necessary. A headphone amp is only helpful for headphones, and you cannot use its outputs to power speakers, nor should you route it to a speaker amplifier.

Conversely, an audio interface provides at least one stereo output for speakers alongside the headphone output.

• Budget

If you are just getting started with music production, I suggest investing in an audio interface as it provides many features at an affordable cost. You can use it for both recording and playback. Furthermore, the interface’s ASIO driver aids your computer by creating a direct route from your computer’s CPU to your DAC.

This feature provides an efficient way for your computer to process audio compared to using the direct line-outs on your computer. On the other hand, a headphone amp is only useful if you already own an audio interface. Furthermore, the needs that make headphone amps essential are highly specific.

So, it’s likely that you do not need to invest in a headphone amp on a limited budget.

Reasons To Pick A Headphone Amp

In general, music producers who already own an audio interface will want to consider purchasing a headphone amp. Similarly, you might need it to listen to traditional music players with only line-outs. Let’s check out the primary reasons to use a headphone amp:

• Quality

If you think about it, there’s no way a $300 audio interface that costs about the same as a branded headphone amp could have the same build and quality. So, it can only mean that either headphone amps are complete scams or they provide something better than an audio interface. In most cases, it’s the latter.

Despite having an excellent DAC, some audio interfaces come with a headphone amplifier with a noise level of 16-bit. Conversely, a genuinely good headphone amp will function at 24-bit and provide noise-free audio. Similarly, sophisticated circuitry with detailed assessment offers a more reliable experience.

• Add More Headphones

Even if you already have an audio interface and are satisfied with your headphone output, you will still need a headphone amp to connect more than one headphone to your interface. Sure, some interfaces come with multiple headphone outputs, but they’re generally limited to two or three and may not be enough. That’s when a headphone amp becomes essential.

However, there’s something to keep in mind here. Suppose you connect your headphone amp to, say, line 1/2 stereo output. You can only get multiple headphone outputs from the 1/2 output. So, you cannot change the volume, pan, or individual tracks’ audibility one each pair of headphones when you use a multi-out headphone amp on one stereo channel.

• Power

People often ask why they would need a dedicated headphone amp if their audio interface can already power a pair of headphones with 250Ω of impedance. Well, let’s talk about my experience with a Focusrite Scarlett 2i2 Gen 3 and a Beyerdynamic DT990 Pro (250Ω).

The pair of headphones didn’t sound as loud as a headphone amp in that setup. So, although it would work just fine for mixing and mastering, it could potentially be unacceptable for recording vocals.

To sum up, here’s a table that will provide more information about the main differences between how an audio interface and a headphone amp work:

Modern Headphone Amps With DAC

While we’re familiar with the most common kind of headphone amps, you’ll find some modern headphone amps with built-in DACs emerging on the market. However, these are generally not produced by pro audio brands. Instead, they tend to be made for the general consumers. So, I don’t recommend them for music production, although they could be an effortless way to listen to high-quality music from your phone or laptop.

Let’s have a look at the advantages and disadvantages these products have:

Advantages

• Convenient

Headphone amps with built-in DACs provide an ergonomic way to bypass the converters built into your computer or phone. If you were to do the same using an interface, you’d have to connect your audio interface to your computer first and then connect the headphone amp to the interface.

This setup will be far too clunky for most average listeners, although it would provide a genuinely high-quality experience.

• Budget

You can find headphone amps with DACs and a USB connection in a wide price range. They can cost as little as $20 or as high as $600+. Of course, the cheaper ones don’t provide the quality as the expensive ones.

Still, even if you take the med-tier products, they are still more affordable than the alternative of buying an audio interface and a headphone amp.

Disadvantages

• Driver

Despite having a DAC, headphone amps do not offer the same features as audio interfaces. I assume you’re familiar with the ASIO protocol, but if you aren’t, I will explain it in the later sections of this article.

Suffice it to say that it’s an indispensable feature for music production that provides CPU efficiency. So, without said feature, the DAC in modern headphone amps only become fit for watching movies and listening to music.

• Unsuitability

As convenient as such headphone amps are for listening to music, they aren’t suitable for music production at all. These devices do not promise flat and transparent audio reproduction, unlike pro audio equipment.

Similarly, if you are producing music, recording audio will become necessary sooner or later. And headphone amps do not feature any inputs or preamps despite their high cost. Furthermore, even if you prefer a headphone amp for monitoring while producing music, you will be forced to switch to an audio interface for recording audio.

Conversely, a regular headphone amp with analog inputs would allow you to use both simultaneously.

Your choice between an audio interface and a headphone should be clear by now. However, if you aren’t familiar with the basics of the two devices about which we’re discussing, let’s get into each in detail:

What Is An Audio Interface?

An audio interface is an electronic device that connects your audio sources like guitars, mics, synths, etc., to your computer and your computer to your speakers or headphones. The set of components responsible for connecting your mic to your computer is an analog-to-digital converter.

It includes a preamp, gain-controls, and various other internal parts that keep your input audio as clean and transparent as possible unless otherwise mentioned.

Similarly, the set of components that connect your computer to your speakers is called a digital-to-analog converter or DAC. However, the speaker output doesn’t contain an amplification system. So, you will require either an amplifier and a pair of passive speakers or a pair of active monitor speakers with built-in amplifiers to listen to your audio interface’s output.

Headphones, on the other hand, do not feature built-in amplifiers. Hence, most audio interfaces provide an alternative output called the headphone output. The headphone output contains an additional component on top of the DAC: a built-in headphone amp.

This amplifier will boost the audio signals from the DAC to make them loud and powerful enough to drive headphones.

However, you’ll notice that some headphones work fine even when plugged into a general speaker output. It’s because these headphones have a low impedance level. Impedance is the amount of resistance to electricity that an electronic device creates.

In other words, higher impedance means it requires more power to function, whereas low impedance means it doesn’t. Furthermore, most studio-quality headphones tend to have a higher impedance to ensure better quality sound and bass response.

So, an audio interface needs to have a powerful headphone amp to ensure it can handle studio headphones.

Furthermore, an audio interface provides other functions. I’ve listed the major ones and described each shortly as follows:

• Connectivity

On top of providing audio input and output, audio interfaces also offer a wider variety of connectivity. Some interfaces work with a USB connection, whereas another might use FireWire or Thunderbolt.

So, after you confirm the compatibility of an audio interface with your computer, it’s the most efficient way to connect your speakers, headphones, mics, instruments, etc., to your computer.

• Multiple Connections

I’ve already described how an audio interface allows you to connect different audio equipment to your computer. However, it’s also important to know that manufacturers design multiple models of audio interfaces to provide you with more than one input and output.

For example, a Focusrite Scarlett Solo has only one mic preamp (with one extra analog input to complete the stereo channel) and a stereo output. Conversely, a Focusrite Scarlett 8i6 has eight inputs (three stereo inputs and one stereo S/PDIF input) and two stereo outputs (and one stereo S/PDIF output). It also features two headphone outputs.

• Phantom Power

The phantom power is a 48v DC electricity that powers a condenser microphone. Most audio interfaces feature a built-in phantom power circuitry ensuring your mic receives a stable and calibrated amount of current with almost no noise. This feature is one of the most significant reasons to purchase an audio interface.

• Direct Monitoring

When you sing into your microphone or play a note on your guitar, the sound might come out some milliseconds after you perform it. This time delay is known as latency.

So, an audio interface provides a feature called Direct Monitoring, which sends the inputted audio straight into your headphones/speakers, bypassing any source of latency. This feature is vital for performing on time when you are recording audio.

• Buffering

An audio interface provides a more direct connection between your computer and your speakers/headphones using a protocol called Audio Stream Input/Output (ASIO). This protocol lets DAW software and plugins use your computer’s CPU much more efficiently. Hence, it will play your music smoothly, without glitches.

What Is A Headphone Amp?

A headphone amp is an audio amplifier that takes analog signals from an audio playback source like an audio interface, computer, phone, CD player, etc., and boosts it so that the signals are loud enough to drive headphones. It does so without adding any noise or spectral changes unless otherwise stated.

Unlike an audio interface, a headphone amp doesn’t connect directly to your computer via a data connection like USB, Thunderbolt, or FireWire. Instead, it only works with an analog audio output. On a computer, this output could either be the Line-Out 3.5mm port on the back of your desktop or the line outputs on your audio interface.

If your headphone amp only accepts a specific type of input (such as RCA, TS, XLR, etc.), you’ll have to convert the output from your playback device into the required jack using a cable or adapter.

The most common application of a headphone amp is often for hi-fi listening rather than for studio use. For example, if you are playing music on a turntable, listening on headphones with an amp is the easiest way to achieve stunning sound quality without spending a fortune on hi-fi speakers and acoustic treatment.

However, that doesn’t mean headphone amps are of no use in a studio. On the contrary, there are many benefits of using one as described below:

• Power

Most professional reference headphones have an impedance of 250Ω, whereas the typical consumer-grade headphones are usually 32Ω. Most audio players (including phones) can power the latter with ease. However, a pair with 250Ω of resistance will require amplification.

So, it’s not uncommon to find that your headphones are way louder or richer-sounding on headphone amps compared to connecting them directly to your computer. Furthermore, although most audio interfaces provide a built-in headphone amp, a dedicated amp is often more powerful.

For example, if you own a Focusrite Scarlett 2i2 Gen 3, the brand recommends headphones with up to 200Ω impedance. Conversely, Scarlett 4i4 and above can easily power up to 250Ω headphones. However, headphone amps are often capable of driving headphones with 250Ω or even higher impedance.

Note that this data doesn’t mean that audio interfaces cannot produce sound on headphones with greater impedance. Instead, these are merely guidelines to ensure your headphones play at their maximum capacity.

For instance, when I used Beyerdynamic DT990 Pro (with 250Ω impedance) on a Scarlett 2i2 Gen 3, the sound was wonderful but slightly not as loud as a headphone amp.

• Multiple Headphones

Many headphone amp models provide more than one output. So, headphone amps are the ideal way to extend the headphone output on your audio interface, computer, CD player, phone, etc.

Having multiple headphone outputs is handy when you are in a studio session with several performers or clients. It provides a way for everyone to listen to what you are hearing on your headphones.

• Quality

While audio interfaces prioritize multi-functionality, headphone amps ensure utmost audio quality. They do so by providing better internal components, quality knobs, less distortion and noise, more bit depth, and a greater sample rate than commercial hardware does.

However, whether or not they are audibly better than an audio interface is up for debate because modern audio interfaces also offer surprisingly distortion-free audio at 24 bit and at least a 96 kHz sample rate.

Still, compared to cheap audio interfaces, you will undoubtedly have a more reliable and consistent experience with headphone amps, thanks to their quality build.

• Compatibility

Since headphone amps connect to any hardware with analog audio output, you can connect a headphone amp to virtually every kind of audio player. These players often include phones, laptops, iPods, turntables, CD/DVD players, cassette players, etc.

However, in a studio, you could use headphones amps to listen to synths, sampler modules, keyboards, etc., with only line-outs on your headphones.

Summary

Now that we’re nearing the end of the article, let’s recap some of what I discussed. The first thing to understand is how different an audio interface is from a headphone amp. An interface is a device for connecting audio sources like mics and guitars to your computer and your computer to speakers and headphones.

However, a headphone amp only amplifies audio to make the signals loud enough for headphones.

In general, if you are a music producer, an audio interface is essential. However, suppose you already own an audio interface and other basic equipment. In that case, you might want to consider getting a headphone amp to increase the volume and quality of your headphones or to play multiple headphones simultaneously.

Au contraire, if you are only a music listener, an audio interface could be clunky and overly expensive. So, you might want to prefer a headphone amp. Furthermore, if you want to bypass your computer or phone’s digital-to-audio converter (DAC), you can use a modern headphone amp with a built-in DAC.

Keep in mind that traditional players like turntables and cassette players do not require DACs, whereas CD players, iPods, etc., do not allow data connections to let you use an external DAC. So, buying an expensive modern headphone amp could become pointless. I hope I have shared some valuable knowledge to help you decide between the two devices. 

K. M. Joshi

K. M. Joshi is a multi-award-winning composer and sound designer, specializing in film, game, and TV audio. He enjoys making cinematic music, rock, blues, and electronica. Read more..