Headphone amplifiers are among the most misunderstood products in audio. They aren’t magical, and to the average person, they’re no more useful than a paperweight. But some wired headphones actually require a dedicated amplifier to reach their full potential, leading to an unbelievable improvement in sound quality. If your fancy new headphones sound a little underwhelming, a headphone amp could be the fix you’re looking for.
What Is a Headphone Amplifier?
Believe it or not, you’re already very familiar with amplifiers. An amplifier is just a tool that pushes an electrical signal to a speaker and causes the speaker to vibrate. When you increase the volume on your phone or laptop, you’re allowing more electricity to run from its amplifier to its speaker, forcing the speaker to vibrate more and produce a louder sound.
Modern devices use low-output amplifiers that don’t eat up a ton of electricity or burn through batteries. To make these low-output amps usable, most headphones and speakers have a “low impedance,” meaning that offer very little resistance to an electrical current and usually reach usable volumes without much power.
But some headphones and speakers, especially recording studio or performance-grade equipment, are “high impedance.” These devices (rated 25 ohms or over) usually require a high-voltage audio source to reach usable volume levels—that’s where good headphone amps come into play. Headphone amplifiers use more power and push out a fatter audio signal than the amps built in most phones and laptops, enabling you to enjoy your fancy headphones on modest equipment.
Of course, these rules aren’t hard and fast. Some high-impedance headphones are sensitive and require very little wattage (which is different from voltage) to reach a high volume. And while a pair of high quality headphones may reach a desirable volume with a low-output source, the limited voltage could lead to audio distortion, hiss, or a lack of bass.
All said, headphone amps can improve the quality of your music by improving the performance of your headphones. Most amps are “transparent” and have no discernible effect on your audio signal, although some companies sell amps that intentionally alter a signal to add an analog “warmth” that’s comparable to the sound of tape or vinyl (usually by cutting select frequencies or adding saturation with an old-fashioned vacuum tube).
Headphone Amps Are Not DACs
Many portable headphone amps double as DACs or “digital-to-analog converters,” but DACs and amplifiers are two entirely different things. As its name implies, a DAC takes a digital signal and turns it into an analog electrical signal for your amp and headphones. All digital audio sources have a built-in DAC, so what’s the point in buying a new one?
Early digital audio equipment, specifically CD players and desktop computers, didn’t always have the best built-in DACs. Improper shielding was a common problem that led to staticy electrical interference, and the low sample rates of consumer-grade DACs could actually distort the high-pitched sound of cymbals or hi-hats.
But these problems are non-existent today—even the cheapest electronics have “transparent” DACs which do not affect audio quality. And while audiophiles argue that on-board DACs aren’t suited for lossless FLAC or WAV files, it’s very difficult (if not impossible) to tell the difference between a modern file encoded at 320kbps its lossless equivalent.
Still, DACs aren’t useless, and you shouldn’t be afraid to buy a headphone amp just because it has a built-in DAC. Headphone amps with onboard DACs plug into your phone or computer’s USB port, enabling you to bypass the device’s built-in headphone jack—a common source of distortion or hiss. Some DACs even feature premade EQ settings and wireless connectivity, which can help you shape your sound or get a more reliable Bluetooth connection while playing music on an old computer or phone.
Do I Need a Headphone Amplifier?
For most people, headphone amplifiers are nothing more than an expensive volume knob with no noticeable effect on audio quality. But headphone amps are often a necessity when you own an expensive pair of headphones, and they can remedy some common problems that appear when using the built-in headphone amp on your computer or phone.
Here are six reasons to buy a headphone amplifier:
- Your headphones don’t get loud enough, lack the expected amount of bass, sound is distorted and hissy, or sound worse than much cheaper headphones on your phone or computer. (This is usually a sign that your headphones are “high impedance” and have an impedance of 25 ohms or more).
- Your phone or computer has an abnormally quiet or crappy-sounding headphone jack compared to other devices in your home.
- The audio jack on your phone or computer is broken and you need to bypass it with a USB DAC.
- You want to add analog “color” or “warmth” to your music (very few amps do this, but they do exist).
- You’re working in a studio environment and need multiple headphone inputs with independent volume controls.
- The volume controls on your computer suck, or you’d prefer to adjust volume with a knob.
You don’t need a headphone amplifier if your headphones are functioning as expected, or if you are using wireless headphones. Also, headphone amplifiers are not a replacement for full-sized speaker amps, although they may help with Bluetooth speakers that sound too quiet in Aux mode.
Which Headphone Amp Should I Buy?
FiiO K5 Pro Headphone Amps Portable Desktop DAC and Amplifier 768K/32Bit and Native DSD512 for Home/PC 6.35mm Headphone Out/RCA Line-Out/Coaxial/Optical Inputs
The FiiO K5 Pro is stylish, practical, and versatile. It can connect to any audio source through its USB input, line input, coaxial, or optical jacks. It also features a 1/4-inch headphone input, stereo line-out jacks for speakers, a large volume knob, and hard switches to adjust gain or flip between different audio sources (which is useful if you want to use the same headphones and speakers for your computer, turntable, radio, etc).
FiiO Headphone Amps Portable DAC USB Type-C coaxial 384kHz/32bit (E10K-TC black)
The small and simple FiiO E10K sits on your desktop and connects to your computer via USB cable. It features a convenient 3.5mm headphone jack and a large volume knob. It also has a rear-panel line output and coaxial output for desktop speakers.
FiiO Q1 Mark II Native DSD DAC & Amplifier for PC/MobilePhone
FiiO's battery-powered Q1 Mark II features a compact design, a comfortably sized volume knob, and a USB-C input for phones, tablets, and laptops. It also features two 3.5mm inputs, and switches to adjust gain or turn on the optional bass-boost mode.
FiiO A1 Silver Portable Headphone Amp A1
The incredibly compact FiiO A1 is the cheapest way to use your studio-grade headphones with a phone or laptop. It plugs into your audio source with a 3.5mm headphone cable and features four optional EQ settings.
Behringer MICROAMP HA400 Ultra-Compact 4 Channel Stereo Headphone Amplifier
Behringer's Microamp HA400 is a cheap and easy solution for musicians or podcasters who need multiple headphone inputs in their studio. It features four independently controlled headphone amps and a 1/4-inch audio input that plugs into your existing audio interface. This amp doesn't have a built-in DAC and cannot connect to computers via USB.
Little Dot MK2 MKII 6J1 X 2 6N6 X 2 Tube Standard Hybrid Headphone Headphone Amp Pre-Amp Tube Amplifier (MKII)
Looking to add a warm analog sound to your music? The Little Dot MK2 headphone amp uses vacuum tubes to achieve the rolled-back high-end and saturated sound of classic audio equipment. It has a large volume knob, a 1/4-inch headphone jack, RCA input and RCA output for speakers.