Everything You Need to Know About Digital-to-Analog Converters
What is a DAC? What does it do? Why do you need one? How does it work?
The DAC is a necessary ingredient to the audiophile recipe. It's one of those components that you can't do without if you're trying to listen to digital music. There are many different kinds of DACs out there, and an infinite number of questions that can be asked about them. This guide is to help you step-by-step in learning about DACs, what they do, and how to find the right one for your audio system and needs.
Table of Contents
We live in a digital age. There was once a time where digital did not exist and everything was analog. In the early days music was recorded using a fully analog signal path. Recording engineers tracked the signal directly from the microphone and recorded it directly to tape or etched into vinyl. The waveforme of the sound captured by the microphone is an analog wave, and through the tracking process, that same waveform makes its way directly to the tape or vinyl. From there, that wave can then be read using a tape or record player, amplified, and sent to a speaker to produce the original sound that was created. There was no need for conversion, since the same waveform was 1:1 reproduced onto a physical medium that could then be used to recreate the original audio though amplification. It was quite a simple process.
Today, things are a little more complicated since digital data accounts for the majority of music recording and playback. Most of the time music recordings are tracked and saved as digital data. The analog wave is sampled at the desired interval and then turned into numbers that are stored on the digital device. (On a CD, the sampling rate is 44,000 samples per second; so, there are 44,000 numbers stored per second of music). That data is then stored onto the disc in order to be decoded later by a CD player or other digital audio player. Depending on the data for a recording, sample and bit rates can be much higher than CD-quality, resulting in what we call High-Resolution Audio (even CD-quality is considered hi res by some when compared to the quantities of MP3 and lower resolution audio). The digital audio player converts this data into an analog signal, and then outputs that to your headphones or speakers. It’s just another way to playback music, albeit with a few more steps and some (arguably) sonic sacrifices all in the name of convenience and modernity.
In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. There are several DAC architectures; the suitability of a DAC for a particular application is determined by figures of merit including resolution, maximum sampling frequency, and others. Digital-to-analog conversion can degrade a signal, so a DAC should be specified that has insignificant errors in terms of the application.
DACs are commonly used in music players to convert digital data streams into analog audio signals. They are also used in televisions and mobile phones to convert digital video data into analog video signals which connect to the screen drivers to display monochrome or color images. These two applications use DACs at opposite ends of the frequency/resolution trade-off. The audio DAC is a low-frequency, high-resolution type while the video DAC is a high-frequency low- to medium-resolution type. Due to the complexity and the need for precisely matched components, all but the most specialized DACs are implemented as integrated circuits (ICs). Discrete DACs would typically be extremely high-speed low resolution power-hungry types, as used in military radar systems. Very high-speed test equipment, especially sampling oscilloscopes, may also use discrete DACs.
The Google Translate of Your Audio System
Our ears can’t hear data, so we need a device that converts this data into an analog format, hence, a digital-to-analog converter (or DAC for short). Sources like AM/FM radio, vinyl (turntable), and tape (tape deck), do not need conversion since they already produce an analog signal. On the other hand, compact discs, digital downloads, and streaming sources are all digital formats that need to be converted to an analog signal before they are able to be heard. This makes the DAC like the “Google translate” of your audio system. The converter is like a “translator” for English to Spanish, or in this case, from digital to analog. It’s only one piece of the puzzle, but it’s an integral one.
The DAC's job is to convert this digital data and translate it back into an analog signal. To do this, it converts the bits of data from the stored files into an analog electrical signal at thousands of set times per second, as mentioned above, called samples. The DAC outputs these samples into a that intersects at all the sample points. However, problems can arise in the conversion process which as we will see later can set some DACs apart from each other.
IF MOST OF MY DEVICES ALREADY HAVE A DAC, WHY DO I NEED ANOTHER ONE?
Phones and computers today are amazing pieces of technology. They do a thousand things well, but in the case of audio, not that great. In the case of recording, most times engineers do not use the mic input on their computer tower to record their audio, so why would you use your standard audio output in the same way? Standalone devices do a much better job at this because they are designed and manufactured to do one thing, and one thing only.
NOT ALL DACS ARE CREATED EQUAL
We could get into a technical conversation about how Apple phones use better DACs than their Android counterparts because Apple was always music-centric in the development of their devices because the iPhone was the natural technological progression from the iPod. But looking at the larger picture, external or standalone DACs are usually far superior. The quality of the converter chip most companies use for their devices is just not that great. Most external DACs are far superior because they have one job: to convert digital signals to analog (and to do it well). That’s it. That’s all they do. Of course, there are differences from DAC to DAC, but the one thing they all have in common is what they were designed to do: to convert digital signals to analog. The audio output from a standalone digital to analog converter is going to be drastically better than your built-in source device like a phone. Why? We’ll get more into that in a little bit.
A DAC FOR EVERY NEED
The next important thing to consider is what type of DAC will you need for your setup? There are a variety of options here depending on your personal audio system and preferences.
The portable DAC is a useful device for those that like to listen to music while on the go or traveling. They can be as small as a thumb drive and are small and affordable solutions for audio improvement. There are a couple of types in this category: USB and battery-powered portable DACs. USB DACs will connect to your computer or tablet with a USB Type-A connection. These DACs are usually convenient to pack in your bag or with your headphones in any scenario and provide a substantial upgrade in the audio output of your device.
DAC solutions for phones or tablets vary depending on your operating system. iPhone/iPod/iPad (iOS) devices are usually connected via Apple’s proprietary lightning connector or the 30-pin connector on older models. Android devices are usually connected via micro USB or USB Type-C which are more popular on newer models now. Smaller, rechargeable battery-powered systems are popular for phones – something you can carry along or attach to your device without adding too much bulk and weight and needing to be tethered to an outlet. These usually plug into the same port you use to charge your device. Just plug in your headphones to the DAC and you’re ready to go. These are great plug-and-play solutions for the frequent traveler or individuals who want an upgraded experience without all the bulk and wires of larger component DACs.
SOLUTIONS FOR DESKTOPS/LAPTOPS
Digital to Analog Converters can also be larger, more hefty units that are suitable for desktop and home system applications. These usually require the unit to be stationary and part of a larger setup. Just connect via a USB Type A cable to an available input on your device and you’ll likely have to set up the output of your computer to the DAC. Most USB DACs also have headphone amplifiers built into the unit so higher-powered headphones that require extra juice should be fine on most desktop devices.
HOME AUDIO SYSTEMS
You’ll be hard-pressed to find a DAC that won’t fit in your home audio system. By far the most versatile input/output options, your component DAC can be configured in a number of ways depending on your source output:
- If connecting from a computer, you can use a USB DAC to connect to your amplifier
- If you have a music streaming device, you can connect a DAC depending on your select inputs/outputs compatibility on those devices (SPDIF, AES, Toslink, etc).
*Note that many source devices such as music streamers, Digital Audio Players (DAPs) and even speakers can be configured with high-end internal DACs. Ultimately you will know what you need for your particular set up – if not, please contact us and we’ll be more than happy to answer any of your configuration or gear questions!
Amp or DAC?
An amplifier provides output power to a set of speakers or headphones. Depending on your application or setup, it might be possible that you need additional power, say if you have headphones that have power-hungry drivers. For example, if you are listening to music on your phone but don’t have enough juice to power your cans, it will result in very poor audio quality (very important to think about especially with portable setups). Also important to consider that apart from poor audio quality, overall volume output will be low too. The headphone amp assists with the volume control of your device, bringing it to line level and providing the necessary "headroom" to drive your headphones well. Luckily, many portable amps are also combined with DACs. The Chord Mojo is an excellent example of this DAC amp combo.
Manufacturers are starting to include DACs in their amplifiers out of convenience also. Before you would have a handful of bulky devices to carry around: your phone, then a DAC, followed by an amplifier, and then your headphones. Now we have all-in-one solutions. Some models allow you to deactivate the specific function depending on your setup also. Just want to use it as a DAC? No problem. Just deactivate the amp/preamp option. But be sure you do your research as all DAC/amps are not as configurable.
If your music source does not have an internal digital to analog converter, then you will need a standalone DAC. Keep in mind that a Digital Audio Player (DAP) will not be able to output a signal to a DAC like a computer or iPod does since it already outputs an analog signal.
If your music source, DAC, or speakers do not include built-in amplifiers (or enough to sufficiently power your output), then you will need a standalone amplifier for your audio system. These are all integral parts of your setup. One device cannot be substituted for another, unless, like spoken about earlier, they are part of a combo device like a DAC/amp.
The nice thing about DAC/amp combos is that they can work with just about any system. Portable units can also work well in desktop or component scenarios just as well as they can on the road. With adapters, you can even use your smartphone as the source, and in cases like the latest iPhones that do not have analog inputs, units like the Chord Mojo can bypass the phone's internal DAC through the lightning port. If you have high-resolution audio files on your phone, then even an audiophile can take the experience with them everywhere.
What is a DAP?
Digital Audio Players are electronic devices capable of storing and playing high-resolution music or media files. Many digital formats, resolutions and encoding exist. Most DAPs can comfortably play most digital files. DAPs are designed to play high resolution or “lossless” digital files.
What Makes A Good DAC?
There are a few things we’ll need to consider before we talk about what sets DACs apart from each other.
We all know there is a difference between CD-quality audio and MP3, but there’s some math behind it too that will be good to know. There are 3 specific aspects of digital music that determine the quality of the recording: bit rate, bit depth, and sample rate.
- Sample Rate - refers to how many samples of data were taken in a second.
- Bit Rate - refers to how much data is being stored per second.
- Bit Depth - refers to how much data is recorded per sample.
The more information/data the recording has then the more faithful reproduction of the original audio recording your DAC can produce. Sometimes the sparser data is (such as in lower resolution files), then mistakes can occur during playback. Some of these issues are known as jitter or phase noise.
WORK SMARTER, NOT HARDER
Jitter ultimately has a negative impact on fidelity. It occurs during playback when there is a loss of a sample or block of samples in a bitstream. It can be caused by a number of factors including sync/word clock error or even buffer issues with the interface. Regardless, it happens with all digital devices and introduces noise, so that is why it’s important to have more data or higher quality recordings for playback to minimize jitter.
Phase noise is another way to characterize the same phenomenon, but interpreting it using the frequency spectrum. Other issues that DACs have to compensate for are narrow dynamic range and limited bit rate. All of these things make it more complicated for DACs to accurately convert the data and accurately recreate the analog signal. That is why high bit and sample rates are preferred. More data also results in high bit depth and dynamic range. MP3s and online files are oftentimes compressed (bit rate), resulting in minimizing the dynamic range and flattening out the sound stage. The more data = the more accurate high-fidelity audio. Of course, this also results in larger file sizes, but that is a conversation for another day.
Another interesting thing to note is that it’s not just about the digital to audio converter chip that matters. You’ll be surprised at how much the overall quality of the DAC also depends on the power supply and the output stage. Two different manufacturers could be using the exact same DAC chip, but because of their different choices in design and build, the DACs can have very different qualities about them. So, keep in mind it’s not just about the chip itself, but the overall components and parts going into the DAC that really helps it stand out from the crowd.
So, we now have a general understanding of what a DAC is, how it works, what it does, etc. Depending on your high-end audio system set up, or how you like to listen to music primarily will depend on what kind of DAC you will need…
We're here to answer all your questions about DACs. Got a question or comment? Contact us via the blog or catch us on social media and we'll be more than happy to give you personal and tailored advice on all things High Fidelity! From all of us here at Moon Audio - Happy Listening!
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FAQs on DACs
What is a DAC?
DAC stands for Digital to Analog Converter. It's a component in your device that processes the digital data of your music and converts it to an analog sound. Once it has been converted to an analog waveform, you can send that to your amplifier and play the music on a speaker or headphone. Think of it as a translator. It's just taking that data and translating it to an analog signal that you can hear.
How Does A DAC Work?
A DAC is essentially the Google Translate of your audio system. Apart from physical analog media like vinyl and tape, most music today is digital. Just 1's and 0's. And since our ears cannot hear digital data, we need a method of converting these 1's and 0's to an analog format so that it can produce sound waves and thus we are then able to hear it. The digital-to-analog converter does just that: converts the digital data to an analog signal. It takes those 1's and 0's and tracks them to a waveform pattern. To do this, it converts the bits of data from the stored files into an analog electrical signal at thousands of set times per second, called samples. The DAC outputs these samples into a waveform that intersects at all the sample points. However, problems can arise in the conversion process which as we will see later that can set some DACs apart from each other. It's an integral part of your system that you can't do without - especially if you have a digital music library.
Why Do We Convert Digital To Analog?
The basic fact is that our ears are not designed to “hear” data. It's impossible. We can only hear analog signals like sound waves and vibrations, coming from an amplified source through the air. Therefore, we need a device that converts this data into an analog signal. The other factor has to do with the fact that most music today is recorded digitally. This means that the analog signals coming from the instruments and voices being recorded are stored digitally onto computers, mixed and mastered, and then optimized for digital mediums such as compact discs or online streaming and downloading. Analog media is making a comeback, but still the majority of music and access to music out there is digital, and ultimately you need something to convert that data before you can hear it.
What Makes A Good DAC?
The quality of the converter chip doesn't necessarily play the biggest role in determining how "good" a DAC is. In fact, the overall audio signal path needs to be considered if we're specifically talking about "sound quality" of a DAC. That being said, factory DAC chips are not very efficient or accurate at converting the data, so the result is a fair presentation of the music, but it leaves much to be desired. A good DAC chip converts the data efficiently and accurately, so that all the information in the data is transmitted to the analog signal. More data points results in a more fluid waveform, thus resulting in better audio quality. Having multiple DAC chips can also make a difference in the effectiveness of the data conversion that is outputted. Higher-end DAC chipsets are usually Cirrus Logic, ESS, AKM or Burr-Brown (of course there are others, but these are some of the most popular on the market). Some DAC's themselves - if we're talking about the device alone - might not even use a chipset. Chord DACs use FPGA and their own proprietary algorithms without utilizing a specific DAC chipset - and they sound phenomenal. Another reason that you can't simply look at the chipset (or lack thereof) to determine if a DAC is good or not. You have to look at the complete picture, or in this case, the whole audio circuit from start to finish.
What Kind of DACs are there?
There are a number of DACs designed for specific purposes and/or sound signatures. Each audio circuit design is unique and provides a different coloration or flavor of the sound. The differences really depend on how you listen to your music. You can divide DACs into their sound signature, ranging from analytical to warm and lush sounding. Here at Moon Audio we typically divide DAC types by ergonomic scenario. Do you travel frequently or do you like to listen to your music while on the go? Then perhaps a portable DAC like the Chord Mojo or Clarus CODA would be appropriate for your personal use. USB DACs are a perfect portable option. Do you like to listen to music in the comfort of your home, or perhaps you have a designated space for your sound system? A desktop or table-top DAC would be a good fit; the Hugo TT 2 is a great option, and the Chord Hugo 2 is a powerful portable DAC that can also serve as a dual purpose DAC in your home system as well. There are many kinds of DACs for varying usage scenarios, and sometimes audiophiles use multiple types - so they always have good audio quality wherever they are.
What Kind of DAC Do I Need?
It depends on your setup. We know that there are portable DACs and table-top units. Do you like to listen to your music untethered and away from your home? Portable units are great options which are usually battery powered and small enough to pair with your phone or digital audio player. Others you can just plug-and-play in your laptop or computer. They are incredibly convenient devices that can easily upgrade your portable device sound. Other options include desktop or table-top DACs that are designed to work within your audiophile system or a desktop computer. These DACs are meant to be left alone, a standalone unit that sits on your desk or shelf as part of your larger home hi-fi system. These are usually more powerful, more expensive, but also have much larger gains in the realm of sound quality.
On the topic of sound signature, you can also pair your system with the natural sound signature of a DAC. All audio components have a natural signature, and depending on your personal listening preferences, you can select a component based on how it will match with the sound of your audio system. If you like a more warm and lush sound when listening to music, then you can either select a DAC that is warmer sounding, or select a more analytical DAC if your speakers or headphones are TOO warm - there's a million combinations you could choose from. It just depends on your system, and what you're looking for in regards to ergonomics and sound signature.
Does An External DAC Make A Difference?
Absolutely. Without a DAC, your digital data cannot be converted to analog sound, and thus you won't be able to hear it. Every device you have that has a speaker has a built-in DAC. Your phone has a DAC in it. Your Airpods have DACs in them. Your tablet and laptop have DACs in them. Your portable speaker you take to the beach - has a DAC in it.
The more important issue here is: not all DACs are created equal. We mentioned that the DAC is like the English to Spanish translation of your audio system. It translates the digital data to an analog sound. Are all language translators the same? No - they vary by skill. The same applies to internal factory DACs and external ones. An external DAC is built to do one thing, and to do that one thing very well. The DAC converts the bits of data from the stored files into an analog electrical signal at thousands of set times per second, called samples. The DAC outputs these samples into a signal that intersects at all the sample points. However, problems can arise in the conversion process that can set some DACs apart from each other. That is why external DACs that are built for the sole purpose of converting this data are better than internal or factory digital to analog converters.
What Devices Do Not Need DACs?
Since the DACs job is to convert digital data, analog sources do not require a converter. Devices like tape decks and turntables are great examples of gear that read directly from analog mediums (tape and vinyl respectively). The device reads the analog signal in real time, and then, through the help of an amplifier, transmits that signal to headphones or speakers. It's an easier and more ‘direct’ process than that of the digital world.
Do I Need A DAC for My DAP?
You will not need a DAC for your DAP, or Digital Audio Player. Most digital audio players come equipped with a high-end digital to analog converter, which attributes to the premium cost of the device. However, upgrading from a Stereo Receiver to a separate Preamp and Amplifier can elevate the sound performance of the system, so too can using the DAP as a digital source and adding a higher performance DAC. For example, if you own the Astell & Kern SP3000 you can use it as the digital source with the Chord Hugo 2. The Hugo 2 provides a superior sound over just the SP3000 by itself, so pairing the two together would result in better sound, but it's not necessary as the DAP already has a high-end DAC chip in the audio circuit.
Do I Need A DAC or An Amplifier?
It depends on your system. A DAC cannot substitute for an amplifier and an amplifier cannot substitute for a DAC. If your system does not have something to convert the digital data to an analog signal, then you will need a DAC. If your system does not have anything to power your speakers or headphones so that it can amplify the analog signal, then you will need an amplifier. Sometimes there are devices that will have both an amplifier and a DAC like the Matrix Audio Element X2. There are many devices - both portable and desktop - that have both a DAC and amplifier. But if you are without one or the other then you aren't going to hear anything. You need both. If you aren't sure about what you have or what you need, shoot us a call or comment and we'll help you out. If you want to learn more about the difference between a DAC and an amplifier, check out our segment “Do I Need A Headphone Amp Or A DAC.”
What Is the Best DAC?
Maybe the better question is, what is the best DAC...for you? There's a lot to consider and each case, each person, will likely have a different answer because - at the end of the day - we all hear differently. And we all have different setups. And we all have different budgets. And on and on. We'll get into proper portable and desktop DAC recommendations in a later video, but keep a few things in mind here when consider what might be the best DAC for you: 1) budget - its a big part in telling you what you'll be able to afford. 2) ergonomics - where are you going to be listening to music? Out and about or sitting at home in your chair? 3) what is your current audio system? DACs have various I/O options, so picking one that is compatible with your current system is key. 4) What type of sound do you prefer? Do you like to get lost in the most and prefer a warm and lush tone? Or do you like to pick out every little detail? Then perhaps an analytical-signature might be better. It all depends, and these factors help determine what is the best DAC FOR YOU. It's how we approach our customer service here at Moon Audio - making sure we help you figure out what works best for your specific system and get your music sound the absolute best it can.