A DAC or Digital Analog Converter (Analog Digital Converter ) is a device which transforms digital signals into analog signals so that they can be heard through speakers or headphones. As you know, the music we hear today usually comes in a digital format. The DAC is responsible for providing the necessary information to the headphones or speakers by transforming/coding that same digital information of “ones” and “zeros” to waves.
We may not realize it, but most of us use some type of analog-digital converter in our homes. They are integrated into computers, tablets, and smartphones. It is a fundamental piece to listen to digital music since it converts digital information into the necessary analog signals for the human ear to perceive them. Any device that acts as a source of a digital sound, whether it’s a CD or Bluray player, gaming consoles or portable audio equipment, needs a DAC.
The traditional amplifiers do not amplify in digital, the speakers do not reproduce in digital and our ears do not listen in digital either: they need analog waves. Without a DAC, our music collection is nothing more than a collection of zeros and ones. The sounds we hear in our day to day, such as traffic, people’s voices, etc …, are transmitted in the form of sound waves, which travel through the air to our ears in an analog signal. The analogical recordings were compiled in vinyl discs and cassettes, but unwanted noises and the fragility of the format gave way to the entrance of the CDs, which began the digital revolution at the end of the 20th century.
You should know that digital audio is very different from analog. Digital files are usually in the form of Pulse Code Modulation (PCM) and are created by measuring the amplitude of the analog music signal at regular intervals. The value of the amplitude is represented as binary numbers and the length of the numbers is usually known as bit depth. The time of the measurement intervals is known as the sampling rate. The digital audio information can be recorded in a variety of sample rates, bit depths, codes, and formats, but regardless of the differences, the work is done by means of a DAC, which translates the binary information as best as possible to recover the original analog recording.
When is an external DAC necessary?
If every device that plays audio has an internal analog digital converter, then why do I want an external one? What happens is that we are talking about sound quality, not whether it sounds or not. An external analog-digital converter can exponentially improve the clarity of the sound.
Every laptop or desktop has a built-in DAC to play the sound stored inside digitally. The problem is that these parts are not of great interest to computer manufacturers. So they use cheap parts and end up being of dubious quality.
Generally, a more expensive DAC will have better audio quality. It generates less noise or distortion when compared to others of lower quality. The better the sound becomes is directly proportional to the money you invest.
For example, a portable of 300 euros produces an annoying noise when connecting the headphones to the included port of the equipment. It has enough volume to notice all the distortions thanks to the quality of the hearing aids. This is when we decided to acquire a DAC to improve the sound quality of what we hear.
How does a DAC work?
A DAC converts a finite abstract number (usually a fixed binary) into a physical quantity (such as voltage). An ideal DAC converts abstract numbers into a conceptual sequence of impulses. That is then processed by a reconstruction filter, using some kind of interpolation to fill the information between the impulses. A DAC can reconstruct the original signal as long as it has the necessary bandwidth to perform the operation. On the other hand, a conventional practical DAC updates the analog voltage at regular sampling intervals, which are interpolated through the reconstruction filter.
How to use a DAC?
It is true that any digital audio equipment requires an analog-digital converter, not all are created with the same quality. For example, some may not support the information of certain audio files. Lower quality converters can introduce unwanted noise during playback, as well as some distortions and Jitters. A Jitter is something like a digital error with time or timing. The timing is vital for digital music. These problems, caused by poor DAC circuits, generate the need to use external circuits to improve sound when using computers or other digital devices.
Of course, to take advantage of a DAC we must use good audio formats. We can not obtain miracles when we reproduce a highly compressed MP3, as in 128 Kbps. We perceive the best results when the DAC works with CD quality or higher, which is well compiled in formats like FLAC, WAV or ALAC (Mac), in addition to PCM formats without loss or DSD.
DAC for PC
Most analog-digital converters only need to be connected via a USB cable to one of the ports on our computer. Some DACs offer other connection options, such as FireWire, which handles audio input and output but does not grant power, unlike USB. There are also sound connection options through an XLR or RCA cable.
DAC for headphones and speakers.
Once we have connected a DAC to the PC, the next step is to synchronize the equipment necessary for the audio output. For music lovers, this can mean connecting the best speakers and headphones through a 3.5mm cable or RCA. This sends the output to an external amplifier to allow the sound experience. Some professional DACs offer us the option of XLR connections. Using a DAC can certainly provide a better sound quality, although this also depends on the other equipment that we have. Using a good DAC may not cause differences in perception if we do not have good headphones.
DAC for laptop, iPhone, tablets, and Android
As we have said, a DAC is used to convert digital information into analog sound signals. The audio DAC is low frequency and high resolution while a video DAC has a high frequency and low resolution. The DACs have contributed a lot to the digital revolution. We can mention, for example, long-distance telephone calls. The voices of the users are converted into electronic signals by a microphone. Then the analog signal is converted back to the digital by a DAC, which does a reverse process to the DAC. The digital information is then divided into connectivity packages so that they can be received. The digital voice is then extracted and assembled,
What DAC to buy?
The analog-digital converters come in various sizes and shapes. It offers different levels of options for connectivity and functionality. So you must think about why you need to use it and the budget that accounts. USB portable DACs offer portability and a reasonable price. They vary between a size no larger than a USB memory, such as the Audioquest DragonFly Black, amplified DACS that fit in a pocket, such as the Oppo’s HA-2 SE, or larger devices for the home computer, for example.
Most of the time they get energy from our computers or equipment. So there is no need for extra sources of energy. They have simple connections, headphone inputs and some line output to synchronize it with sound systems. If you need more connectivity and do not worry about moving the device, a larger desktop DAC unit may be a good option. These require their own power source but offer additional audio inputs. There are also devices designed to work as part of a large home audio system. These have more entries, such as AES / EBU, and other additional features. They support the full range of high fidelity sound formats. And can also offer Bluetooth connectivity for use with phones or tablets.
What is the best DAC in the market?
One of the most frequent questions is, which one we should buy. We divided the DAC types into three, according to their quality and price: A, B, and C.
- A class A analog-digital converter is for those users who are really looking for the best sound quality. These are used by the most demanding audiophiles in order to get the highest quality and fidelity.
- A class B converter is enough for most fans. In general, a class B would be the best option in terms of quality/price. Its sound quality and price are lower than Class A DACs.
- Finally, class C devices are better suited to those users accustomed to the portable world. Or those who seek an easy way out of their connection problems. These DACs do not have to sound bad, they are simply more versatile. These devices can replace, perfectly, a common sound card and are the best economic option.
We have written an additional article in which we review the best DACs of the market.