What is DAC and How Does it Work?

DACs are often found in televisions, mobile phones, headphones, and many other electronic devices. DAC has become an indispensable part of everyday life. But how many of you are familiar with DAC? I’m sure most of you don’t. If that’s the case, you’ve come to the right place. In this article, we will go over everything about DAC, including its description, benefits, uses, and types. 

However, choosing the right one makes a huge difference. Indeed, acquiring a high-quality DAC lets you enjoy the premium sound quality and enhances the overall audio experience. Dive into the article to know more.

What is a DAC?

A DAC also popularly known as a Digital to Analog Converter device is commonly used in most electronic gadgets. They convert digital audio information consisting of 0’s and 1’s into analog audio signals. The audio signals are amplified by the audio equipment to drive headphones (or) loudspeakers (or) music players. This audio conversion process enables audio systems to reproduce accurate and high-quality sound for a better audio experience. 

How Does a DAC Work?

Firstly, to know how a DAC works, we must essentially understand both analog and digital signals.

1. Analog Signal

An analog audio signal is a wave in which the voltage, current, or physical quantity varies continuously and indefinitely according to a time-varying parameter. Radio waves, television waves, and sound waves are examples of analog signals. 

Typically, these signals are continuous which varies with time, and resembles a sine wave. They can be either periodic or non-periodic. Moreover, when these signals travel through the medium, they are vulnerable to more noise, which causes information loss in the signal. 

2. Digital Signal

A digital signal encodes information as a series of discrete numbers. A digital signal can only have one value from a finite range of potential values at any time. Many physical quantities, such as variable electric current or voltage, can be utilized to represent information in digital signals.

Fundamentally, these signals are not continuous and are represented as square waves (or) clock signals. They are less susceptible to noise than analog signals. 

Difference Between Analog and Digital Signals

Now, let’s get to know the working process of the Digital Analog Converter (DAC).

1. A digital-to-analog converter converts sounds from one source to another. The audio is sent to the DAC in the form of digital electrical impulses encoded with binary data.
2. This binary data is simply a series of 1s and 0s which are the chunks of digital information that will be sent to the DAC.
3. The DAC then converts the digital data into analog sound waves. These sound waves are then sent to the headphones (or) other listening devices attached to the DAC, allowing the user to hear the audio.
4. The small computer inside the DAC takes snapshots of these audio signals every few microseconds. Therefore, these snapshots are called “Samples”
5. Then the samples are translated into voltage levels. Now, the computer measures these voltage levels and assigns binary numbers for each sample.
6. The number of measurements taken for each second is called the “Sample rate”.
7. Once after taking the sample rate the processed digital data is finally converted into an analog sound signal that we actually hear.
8. The samples are converted back to the voltage levels via DAC.
9. Later a low-pass filter is applied to these voltage levels to smooth out any irregularities in the sine wave.
10. Now, the audio is sent to the headphones, speakers (or) other devices that are attached to the DAC’s output connection.
11. DACs retain audio quality by eliminating unwanted sounds like distortion, hissing, popping (or) wrapping.

And that’s it, this is exactly how a DAC works. Therefore, you can enjoy the best sound quality that is far superior to what your device’s sound card produces by using DACs. 

Types of DAC

Digital analog converters are classified into four types which are stated below.

1. Binary Weighted Resistor DAC
2. R-2R Ladder DAC
3. USB DAC
4. Segmented DAC
5. Delta-Sigma DAC
6. Bluetooth DAC
7. Portable DAC
8. Hybrid DAC

1. Binary Weighted Resistor DAC

This DAC requires one resistor (or) current source to convert every digital input bit into an analog output. These resistors connect the inputs with the summing amplifier circuit to generate the output.

2. R-2R Ladder DAC

This type of DAC has only two values of Resistors R and 2R. The conversion speed decreases in this DAC due to parasitic capacitance. It is the simplest type of DAC where the switch between the ground and inverting input of the Op-amplifier is controlled by the input bit.

3. USB DAC

USB DACs are most commonly used with computers and are powered by the USB ports on your computer. These types of DACs usually have a built-in amplifier to boost the audio volume to an audible level, especially the more portable USB DACs.

4. Segmented DAC

Segmented DACs are designed according to the specifications based on performance. Furthermore, no architecture is perfect, thus they are created by merging two or more Binary Weighted and Thermometer-coded DACs. The binary code input is divided into two separate components. MSB employs thermometer coding, while LSB employs a binary-weighted structure. 

5. Delta-Sigma DAC

Delta-sigma DAC is the fastest and highest precision DAC consisting of different blocks. 

1. Interpolation filter

2. Delta-sigma modulator

3. 1-Bit DAC

4. Analog output filter

• The interpolation filter multiplies the sample rate and frequency by four, lowering the time. The filter output is sent into the modulator block as an input. 
• The Delta-Sigma Modulator acts as a High-Pass Filter for quantization noise and a Low-Pass Filter for the signal. It transforms data into a high-speed bit stream.
• 1-Bit DAC converts Digital samples back into Analog form for further amplification. Therefore, each digital sample bit is converted serially into an analog signal.
• Finally, the analog output from the DAC is filtered out by the Analog output filter, which eliminates any distortions, hissings (or) poppings to provide high-quality sound. 

6. Bluetooth DAC

Bluetooth DACs, also known as wireless DACs, have a battery that has to be charged for the DAC to function. Because of this, many of them are portable and can be used with your smartphone as you go about your day.

7. Portable DAC

Portable DACs often come with a built-in battery that can be charged so that the DAC may be used without being plugged into a  power source. These DACs are ideal for listening to high-fidelity audio while exercising or going about your daily activities. Some even have a clip on the back so you can attach it to your clothes.

8. Hybrid DAC

A data processor, one first-type DAC, one second-type DAC, and an output circuit comprise a hybrid digital-to-analog converter. The data processor turns an input digital signal into one of two digital signals, which correspond to the upper and lower bit halves of the input digital signal, respectively. The first digital signal is sent by the data processor to the first type DAC, which converts it. The digital signal is then received and converted by the second type of DAC. Finally, the output circuit accepts the output signals of the first and second-type DACs and outputs an analog signal.

Applications of DACs

The applications of Digital to Analog Converter as listed below.

• DACs are used in Digital Signal Processing.
• They are also used in digital power supplies for Micro-controller.
• DACs are used in digital potentiometers.
• They are used in all digital data acquisition systems.

Benefits of DACs

Here are some of the benefits of digital-analog converters.

1. Improved Sound Quality

DACs offer better sound quality when compared to amplifiers. They produce accurate analog signals from digital sources by reducing (or) eliminating noise and distortion. 

2. Lower Latency

DACs also provide low latency. The generated analog audio signals are faster and more immersive meaning that the audio is in synchronous with the visuals you see on the screen. 

3. High-Resolution Audio Files

DACs deliver high-resolution audio files with clear sound and great sound quality.

4. Compatibility

DACs are compatible with all devices including smartphones, computers, and other electronic gadgets as well. Simply connect your device with DAC and you are ready to use it. 

5. Customization

Many high-end DACs come with customizable options i.e. you can adjust the output volume by adjusting the filters based on your preference.

6. Simple Set Up

Anyone can set up DAC easily by following the instructions carefully. Just connect your device with DAC via cables and go along the steps for a successful installation. 

How Do We Need a DAC?

1. Identify The Type of DAC You Need

Firstly, it is very important to choose the right DAC that meets your needs. You are free to select any DAC including delta-sigma DACs, R-2R ladder DACs, Hybrid DACs, etc that come with different features and capabilities. 

2. Pick a Suitable DAC Chip

A DAC chip is the DAC’s heart, determining its performance. So, after selecting a suitable DAC, it is vital to select an ideal chip for the DAC. Burr-Brown, AKM, and ESS Sabre are three common DAC chips.

However, while choosing a DAC chip, keep the following aspects in mind.

• Specifications
• Performance
• Price
• Durability

3. Understanding DAC Circuit

One must have a basic knowledge of digital signal processing and analog circuits, as well as inputs, outputs, and voltage levels to make the most out of DAC. 

4. Choose The Right Output Stage

Single-ended and balanced output stages are the popular output stages. Choosing the right one among these can make a great difference in sound quality and also affects its performance. Therefore, the output stage is responsible for transmitting analog signals to the speakers (or) headphones (or) any other audio devices.

5. Assemble The DAC

 Finally, once you are done with choosing the right DAC, perfect chip, understanding the circuit, and selecting the preferred output stage you have to assemble all these things.

How to Choose a DAC?

Consider the following things while selecting a DAC.

1. Compatible Device

Pick the device that is compatible with DAC. Indeed, some devices come with an in-built DAC, eliminating the need of purchasing additional equipment. If you are opting for the devices with built-in DAC, go for the high-quality ones that produce premium sound quality. 

2. Purpose

First, decide the purpose of purchasing the DAC, whether it is for personal use, professional recording (or) Djs. Basically, indoor enthusiasts may not require a portable DAC whereas outdoor aficionados need a portable DAC with batteries.

3. Audio Quality

Different DACs will come with different audio quality. Opt for the ones that are reliable and offer optimal sound quality.

4. Portability

If you are planning to buy DAC for outdoor purposes, then choose a portable DAC that comes with extra batteries and additional features. 

5. Reviews

Reading reviews from other users might help you to figure out what to expect from different DACs. You can check reviews on Amazon, BestBuy, B&H, and other online shops.

6. Brand

Prefer branded DACs that are reliable and trustworthy. Choosing a reputed band can give you peace of mind as they offer good  services and are less prone to repairs (or) damages. Gustard, FIIO, Auris, IFI, etc are some examples of DAC brands.

7. Cost

Many DACs are readily available in the market with different price tags. Select the efficient one, that offers optimal sound quality, and is budget-friendly.

Summing up, this is all about DACs. We hope this acts as the perfect companion before purchasing the right DAC corresponding to your needs. Moreover, the audio files can also affect the quality of the output. Lossless files, such as FLAC and Apple Lossless preserve the audio quality, while lossy format files, such as MP3 and AAC, compress audio data resulting in the loss of audio quality.

What is DAC and How Does it Work FAQs –