Note: This article was first published on 8 April 2017 and it's still relevant today.
DAC stands for Digital-to-Analog Converter.
As its name suggests, it takes digital audio information and converts them into an analog signal so that it can be amplified and played by headphones or speakers. This is necessary because most music are stored digitally today. Music on CDs, MP3 or FLAC files are all examples of digitally-stored music. Headphones and speakers cannot make sense of digital data. Countless number of digital devices, such as smartphones, tablets, notebooks, televisions, and even bedside clock radios have DACs built into them.
You don’t really need an external DAC, but if you are concerned about audio fidelity, an external DAC can really help improve things. This is because DACs used in devices are usually very basic. But that aside, because they are crammed into a small space along with other components, they can be susceptible to interference, which introduces unwanted noise and artifacts into the sound. In addition, internal DACs might not support all file types and might also suffer from distortion due to jitter, or timing errors that occur between your source and the DAC.
They are many, but let’s start with greater support for all file types. If you are serious about audio, you might have high-resolution audio files with higher bit rates and sampling rates, or you might even have DSD files. These types of digital audio files usually require a more capable DAC to properly decode. In addition, external DACs with asynchronous USB modes can also reduce jitter by taking over control of timing duties from your source.
Most portable DACs these days come with a headphone amplifier. And what a headphone amplifier does is simply amplify the analog signals that has been converted by a DAC. Headphone amplifiers are necessary if you happen to have a headphone that has very high impedance levels or low sensitivity. If you find that the volume of your headphones are too low even after turning them up, then you will need a headphone amplifier.
If you have any more questions, leave a comment below and I will try my best to answer them.
Specifications are not everything. It's what you do with what you have that matters.