In order to choose the best headphone amplifier, you will need to consider factors such as the type of headphones you use, the sound quality you desire, and your budget. It is often possible to locate inexpensive headphone amplifiers, and there are even do-it-yourself (DIY) plans available on the Internet, though high end units are very costly. If sound quality is important to you, then you will typically want to look for a headphone amplifier with a low output impedance. Other features, such as a crossfeed that blends the audio channels to some degree, may also improve your listening experience. Some headphones call for a specific type of amplifier, such as electrostatic headphones that require a substantial amount of power to operate.
There are many different types of headphone amplifiers available, so choosing the best one can depend on your own personal listening habits. One of the first items to consider when you begin looking for a headphone amplifier is the type of headphones you use. If you use simple, inexpensive earbuds, then investing in a high end headphone amplifier may not make sense. Some headphones have specific requirements though, such as electrostatic units that need a lot of power to operate. If you have a set of electrostatic headphones, you will typically need a power amplifier that includes a step-up transformer.
Headphone amplifier sound quality is not always dictated entirely by price, and there are a few different specifications you may want to look at. In order to get an amplifier with the best sound quality, you will want to choose one with low output impedance. An impedance of between about 20 and 50 Ohms is typically satisfactory, but units with an even lower specification can provide less distortion. You may also want to look at factors such as frequency response, total harmonic distortion and minimum load impedance to choose the best headphone amplifier.
Some headphone amplifiers also offer features that may improve your listening experience. Volume controls, bass boost, and other adjustments can allow you to set your audio to the exact levels you prefer. Crosfeeding is another feature that you may appreciate, especially if you have ever experienced a headache when listening to music with headphones. Since the channels mix naturally when listening to speakers, this feature can create the illusion that you are not using headphones at all. Digital signal processing (DSP) amplifiers can take this even further, using phase differences to simulate surround sound.