If you identify as an audiophile or music lover, then it’s likely you already have a hi-fi home speaker system that pairs the right components and amplifiers to give you crisp playback. It’s a given that turntables require power amplifiers in order to blast our favorite albums through the loudspeakers. But playing music through headphones can feel like a completely different animal. This begs the question: do you need a headphone amplifier?
Over-ear headphones and earbuds don’t always provide the high-end sound quality that you’re looking for, even from a nice system playing high-quality recordings. Luckily, a headphone amplifier can improve the sound quality and be a game-changer. Before you spring for any random headphone amp, it’s helpful to sort through all the factors.
What is a Headphone Amplifier?
First things first, it’s important to clarify what a headphone amp even is. A headphone amplifier is a tool that connects to your music player, whether you’re using a computer, any iPhone iOS, an Apple iPad, or Android device. The digital component allows for you to hear formats ranging from MP3s to MQA and beyond, and the amp increases the volume levels and the hi-res amplification heard through a pair of headphones during playback. The amplifiers effectively push the audio signal to the speakers via vibrations that are converted into sound waves. In layman’s terms, it functions in the same way that large power amplifiers do, but on a smaller scale.
What is a DAC?
Most portable headphone amps often double as a digital-to-analog converter or a DAC. A DAC’s job is to convert digital audio information into a low-voltage signal that an amplifier can easily amplify.
Analog music sources like turntables or tape decks don’t need a DAC because they already put out analog low-voltage signals. But digital audio devices like PCs, smartphones, iPods, or tablets often need both a DAC and headphone amp in order for you to hear sound through your headphones. These audio converters are found in all digital audio sources, but built-in DAC combos don’t always provide high-quality amplification on their own.
What is the purpose of a Headphone Amp?
Given the fact that most (there are exceptions) headphones deliver you sound without a headamp, you may still be wondering why you’d want one. The purpose of a headphone amp is to improve the sound, add volume control options, and to allow you to enjoy more nuance and detail. If you’re using a multi-channel headphone amplifier, you have the option to play both mono and stereo records. If your volume knob is broken, you can shift volume with the one on the amplifier.
In short, headphone amps not only improve your listening experience, but they sometimes extend the shelf-life of the equipment you already have beyond the warranty.
How does a Headphone Amp affect your volume quality?
There are two main aspects of playback that affect the quality of your volume: impedance and sensitivity. Headphones that have a higher sensitivity rating tend to have a louder volume, because they’re picking more up. While high sensitivity can be great for picking up musical detail, it also means you might pick up sounds on the amplifier, electrical noises, and other sounds without a high-quality amplifier. This can get especially unpleasant when the music you’re listening to has a lot of treble, and the sensitivity makes it spike or blip in unpleasant ways.
What is impedance?
The second aspect that affects the sound of your music is impedance. Impedance is the resistance of an electrical signal, the higher the impedance, the more resistance a pair of headphones or speakers will give to an electrical signal. A simpler way to imagine impedance is to compare your electrical signal to water running through a hose. If there is nothing blocking the spout of the hose, the water runs quickly with no resistance. But if you place a finger on the hose, thus making the hole for water smaller, there is an increased resistance and it doesn’t come out as easily or quickly. Higher impedance, means the hose spout is blocked more, while lower impedance means it’s open/free to flow.
When looking at headsets, impedance is measured in ohms, which are rated using a large range from 16 to 600. The lower the rating is, the louder the music will sound. Most of today’s headphones are released with a low impedance rating because a higher rating means that more power is needed. When things take more power to function, a traditional power supply is typically not enough.
Does a Headphone Amp always give you better sound quality?
The first step to improving your sound quality is to figure out what has been affecting your sound. If you’re dealing with a lot of distortion, chances are your headphones have low impedance.
You will get more volume, but is added distortion in your music really worth getting a pair of low-cost headphones that don’t require an amp? Of course not, you need to find a good balance that works for your ears, especially if you listen to low frequencies often that amplify the distortion. Low impedance headphones will not have adequate impulse response and dampening, which can also create muddy mids and bass that degrades the quality of your music.
What Type of Headphone Amplifier Should I Purchase?
main kinds of headphone amps, all with equally valid and helpful purposes.
Here’s a breakdown of each amp type so that you know which unit to purchase for your headphones.
Portable headphone amp
These are small enough to fit inside your pocket yet enhance the sound output coming out of your smartphone or MP3 player’s 3.5mm jack. There are two jacks on these: one sends a two-end wire to your audio device and the other plugs into your headphones. Since these are separate from your headphones and audio device, they will need to be charged from time to time. Also, if the audio jack on your player is broken, a USB DAC, like Pro-Ject’s DAC Box E Mobile allows you to easily override the malfunctioning component and keep listening to your favorite tunes.
Desktop headphone amp
Unlike portable units, desktop amps sometimes have multiple inputs for headphones and sometimes accommodate studio monitors. These are in no way portable and are designed to sit atop a desk or shelf. Sometimes, these have a large volume rocker for nuanced control. If you spend a lot of time at your computer, investing in a desktop headphone amp like the Head Box DS2B is a surefire way to complete your computer set-up. With an easily accessible volume knob, you can adjust the sound as needed while you do your work.
Rackmount amp
If you have a studio signal processor, then a rackmount system is best. This is a headphone amp that is easily daisy-chained with your other equipment, like preamps. You can even connect them to other racked headphone amplifier systems for more inputs, though most will have up to six jacks already. These are designed to accommodate 19-inch wide racks. Rackmounts are ideal for anyone who works with professional audio mixers, because you can power a lot of headphones at once without sacrificing the ability to hear individual nuance and detail.
What features should I look for in a DAC or Headphone Amplifier?
Before making a purchase, here are a few criteria to consider that will help you decide on your best potential device:
Pick out your form
This will decide the type of headphone amp you’re purchasing. Are you looking for a portable unit, one that’ll fit on a desk, or one that will fit in amongst a racked system with additional devices like preamplifiers? If you’re not going to be using your system on the go and you don’t have additional audio equipment, then in most cases, a desktop headphone amplifier will do the job.
The audio technology
Headphone amps use digital-to-analog converters (DACs) to convert a digital signal to an analog one. At the device level, your music is arranged using pulse code modulation (PCM) to make analog music digital.
The DACs use a variety of technologies, including direct stream digital (DSD) and super audio CD (SACD), to convert data so that it becomes high-fidelity audio. While DACs are present in devices like your smartphone and your laptop, it’s critical to have a higher quality DAC in place to capture all the nuance of your music.
Confirm your output type
This is a major consideration because the output type will directly affect sound quality. For example, with RCA or coaxial connectors, which have a single, unbalanced pin, you may lose signal quality if your cabling is on the longer side. Alternatively, a balanced three-pin XLR cable allows you to transfer the sound signal over a longer distance without degradation. The type of output cabling is exterior to your headphone cabling and leads directly to the sound system. You can easily manually double check to see what kind of output you need.
Which headphones DON’T need amplifiers?
If you currently use noise canceling headphones, you don’t need a headphone amp. Noise-canceling headphones have a built-in headphone amp inside that prevents outside headphone amps from significantly improving sound. Whether you are listening to music through a Bluetooth connection or a headphone jack, headphones that already have an amplifier built into the model will prevent an external amp from making changes to the headphone output, which simply makes them a volume knob that costs a lot of money.
In-ear monitors that are used by live performers often don’t need additional amplification because they’re already designed to amplify a specific part of the sound being produced. Headphone amplifiers are designed to be used with over-ear studio headphones.
Another way to figure out if you need headphone amps or not, is to check the impedance level. If your headphones have an impedance above 50 ohms, a headphone amp is generally a necessity. If your headphones have an impedance under 32 ohms, they’ll work fine without headphone amps, but you might still want to invest for quality’s sake.
A few final considerations on what to look for
Feeling unsure whether you want to spring for an amp or not yet? Here’s a few other factors to keep in mind.
If you are using aptX technology over Bluetooth headphones or earpods that connect to your iPhone wirelessly, having an amplifier can really take your music up a notch. Some say that there is no noticeable audio difference between a recording at 44.1kHz and 96kHz, but with the right headphone amplifier, your music can have an exceptional sound, regardless of the sample rate.
However, for vinyl hi-fi listeners, it’s important to consider that if you take amplifying your turntable seriously, you should take amplifying your headphones seriously as well. If you’ve optimized your turntable setup for tonearm resonance and alignment, taking this additional step can bring your closer to your favorite music on every spin.
There is an ultimate audio setup for every type of listener, just make sure that your mobile audio system has the same quality sound as your home system.