What is a DAC?

A DAC (Digital to Analog Converter) is a device that converts a digital signal into an analog signal. More specifically, it converts the signal received from the digital source which is in the form of ones and zeros into an analog audio signal that can be sent to a headphone amplifier. If you were to separate all of the steps that happen in a headphone audio system, it would look like this:

A Digital Source → DAC → Amplifier → A Pair of Headphones → Your Ears.

This is also called the ‘signal path’. The DAC takes the signal from the digital source (eg. streamer, music server, CD transport, hard drive, music library on your computer, etc.), converts it to an analog signal so that the amplifier can amplify the signal to a level that can be received and turned into sound waves by the headphones. In most cases, you cannot connect a headphone directly into a DAC. A headphone amplifier must serve as the intermediary step between a DAC and your headphones.

Headphone DAC

Is the DAC important?

The DAC is a critical component because the better this conversion, the better the sound quality. It is responsible for converting the information from digital form into a form that can be experienced as music. As the quality of the DAC improves, the sound becomes purer, more accurate to the original recording, cleaner with less distortion and more natural sounding. The better the DAC, the better the communication, or expression of all the details in the music file. A great DAC will ensure that you can hear as much information as possible in a coherent manner so that all of the musical details, the timing, phase & spatial information is present.

Types of DACs

If you are listening to music from your smartphone/laptop/tablet for example, the digital source, the DAC and the Amplifier are all contained within your device. If your headphones require more power or you simply wish to enjoy the benefits of a high-quality separate amplifier, then the separate amplifier does the job of amplification but the digital source and DAC functions are still being performed by your smartphone/laptop/tablet. Sometimes, DACs are integrated into the digital source or integrated into the amplifier.

However, for ultimate sound quality, it is preferable to separate all of the components in the signal path and use a separate dedicated DAC. The increase in sound quality can be substantial because a dedicated DAC will often use higher quality chipsets, components and design topology as well as have its own dedicated isolated power supply. All of these technologies increase resolution, lower the noise floor and better maintain the purity of the signal.

Eleven Audio Sagra DAC

What is an analog signal?

An analog audio signal is a continuously varying voltage that perfectly represents (or is ‘analogous’) to the continuously varying sound wave that you hear when you are listening to music. When an artist is being recorded, a microphone turns incoming sounds into an analog electrical signal representing those sounds. This signal is then processed by an analog to digital converter and then stored as a series of numbers on a hard-drive or memory of an audio device. Computers are made up of a large number of switches that can either be on or off and these states correspond to the binary representation 1 (on) and 0 (off). Each 1 (on) or 0 (off) state in a single switch is called a bit, which is the smallest piece of data a computer can store. By having lots of switches, computers can process these bits of information and in this case, store and play this data as music files.

A CD disc stores these samples as 16-bit binary (1s and 0s) “words” 44,100 times a second – aka 16-bit/44kHz files – but digital audio data can be stored in a variety of sample rates, word sizes, and encoding or compression formats.

A DAC is the device that converts these digital 1s and 0s back into an analog audio signal that is a continuously varying voltage signal. This analog signal can be sent to a headphone amplifier and then on to your headphones.

Headphone DAC

Do different DACs sound different?

Yes they sure do! However, it is important to remember that the biggest difference in sound quality is achieved by going from an integrated or built-in DAC to a stand-alone, separate DAC. If you already have a stand-alone DAC, differences from one to the next won’t be as significant. DAC’s sound different because the technologies used in each DAC can be different. We encourage you to try different DACs to find out which type of sound you enjoy most.

Looking at DAC specifications is often not very helpful, because they often contain information like bit depth and sample rates that don’t have any tangible impact on the sound quality, such as 32bit at 768khz (samples per second). It’s simply not possible to determine the quality of a DAC just by looking at specs alone. The only way is to listen to the DAC!

Some useful tips

Low resolution (low bitrate) music files such as MP3 files will always lack important musical information which can be described as detail and dynamics. You can still enjoy your favourite music, but if you are looking for better headphone sound quality, it is recommended that you rip your digital music in uncompressed formats or at the highest possible bitrate.

Remember that an audio system is only as good as its weakest link. If you have well-recorded music, a high-performance amplifier and great audiophile headphones but are relying on the low quality DAC inside your phone/laptop/tablet, there’s no way that you will be hearing your headphones at their full potential.

Headphone DAC