What is a DAC? The First Gear to Buy
Truth be told, I am still at the stage of building my knowledge as I enter the world of audio. I have organized the lessons I learned while swapping out gear to understand this delicate process of sound conversion into a “Three-Part DAC Special Series” for fellow beginners like myself.
The audio field is deeply nuanced with many experts, so I approach this writing with a sense of caution. If there are any areas that need supplementing, or if those with deeper expertise have insights, I warmly welcome your input. I believe the true charm of an audio hobby lies in the process of sharing knowledge and learning together.
What happens when we press the play button on our smartphones or PCs is one of the most sophisticated signal conversion processes achieved by modern engineering.
Sound is fundamentally a physical wave caused by changes in air density. Let’s calmly follow the fascinating path of how these invisible analog waves turn into numbers (0s and 1s), only to return as physical energy that vibrates our eardrums.
A Beginner’s Guide to DACs: 3-Part Series
- Part 1: What is an Audio DAC? The First Gear to Buy When Sound Feels Dull
- Part 2: A 1-Minute Guide to Decoding DAC Specs for Beginners: 24-bit? SNR?
- Part 3: Which DAC Should I Buy? A Key Chipset Guide to Finding Your Sound
Preserving Analog Signals as Continuous Numbers (ADC and PCM)
For an artist’s sound to be recorded, it must first be converted into electricity. As the studio microphone captures sound waves and converts them into minute voltage changes, an ADC (Analog-to-Digital Converter) steps in to translate them into numbers. The ADC breaks the continuous wave of sound into tiny units of time and records them as digits.
Gemini. Analog → Digital → Analog
To put it simply, an ADC is like a “high-speed burst mode” camera taking tens of thousands of photos of a moving person every second. If you play those photos back quickly, they form a seamless video—the exact same principle applies here. The most widely used digital format in the audio industry is PCM (Pulse Code Modulation). The framework for the WAV or FLAC files we commonly see is this PCM method.
Wikipedia. Comparison of analog and digital recording
The photo above is an example of an audio file sampled using 4 bits (2^4), showing the process of sampling a red signal with blue dots. In the case of 24-bit high-resolution PCM audio that we listen to, the sound volume is recorded by dividing it into approximately 16 million (2^24) precise and dense increments. Only when these numbers are perfectly aligned does the data take the form of the audio files we know.
What is a DAC? The Conductor Resurrecting Sound
The protagonist of this three-part series, the DAC (Digital-to-Analog Converter), is exactly what its name implies: a converter that turns Digital (D) into Analog (A).
The sole reason for this device’s existence is to take audio data stored as binary 0s and 1s in computers and smartphones and revert it back into smooth electrical waves that we can hear. Interestingly, there are already many DAC devices hidden all around us.
(Left) Daiso Mall. Aux to C-type Adapter, (Right) SoriShop. Wadax DAC
From a $2 smartphone earphone dongle to a $200,000 high-end stationary audio system, and even the professional audio interfaces musicians use for recording, the shells may look vastly different, but their essence is the same.
(Left-Bottom) SMSL DS20 Portable DAC/AMP, (Right-Top) SMSL DO400 Stationary DAC/AMP
I once saw someone in an audio community misunderstand that “the iPhone’s C-type earphone adapter is not a DAC.” However, if it receives a digital signal (USB-C) and outputs sound to analog earphones, there must be a small DAC chipset inside that thin cable to convert the numbers into electricity.
In short, if an electronic device produces sound on its own or through connected earphones, you can assume a DAC is working somewhere inside.
The Flow of DACs via Cable Terminals: Digital Input and Analog Output
Once you understand the conversion principle of a DAC, the roles of the complex ports on your devices become intuitive. In a DAC, ‘D (Digital)’ refers to the input section that receives data, and ‘A (Analog)’ refers to the output section that transmits sound.
In other words, a DAC is a one-way device that must:
- Receive signals from a device via digital terminals (USB-C, USB-A, Optical, Coaxial, etc.).
- Send signals via analog terminals (3.5mm AUX, 4.4mm balanced, RCA, speaker wire, etc.).
“Can I plug a C-to-C cable into a DAC to listen to speakers?”
Do you see now why this configuration is impossible? Since a USB-C terminal is a digital (D) pathway, it cannot output analog (A) sound waveforms. Knowing this clear rule helps beginners avoid common cable-matching mistakes.
“Can I unplug a cable from a DAP’s 4.4mm terminal and plug it into another DAC?”
You no longer need to ask this question either. You cannot force a sound that has already been converted into analog (A) via the device’s 4.4mm terminal into the digital (D) data input terminal of another DAC.
Physical DAC connections always flow in the direction of “Digital cable to Analog cable.”
Why Do Audiophiles Insist on a Separate ‘DAC’?
Why use a DAC at all?
If my smartphone and PC motherboard already have decent DACs inside, why go through the trouble of buying heavy, cumbersome gear for hundreds of dollars? This was the first question I had when entering the audio hobby, and one I held onto for a long time. Now, after trying out countless devices, I believe there are three main reasons for seeking a standalone DAC.
First is ‘Precision and Accuracy.’
Budget basic DACs often cause minute distortions when converting signals to analog, or the waveform may be crushed due to the chipset’s computational limits. High-performance DACs process signals without error based on precise clock components, drawing much smoother and clearer sound contours.
Tech Insights. Samsung Galaxy S10-Teardown
Second is ‘Complete Isolation from Noise.’
Looking inside a smartphone or PC, you will see components like CPUs, GPUs, memory, and wireless modems packed together, causing tremendous Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI). Analog sound signals are vulnerable to these electromagnetic environments. This often results in background “hissing” (white noise) and blurred boundaries between instruments. Conversely, external DACs receive clean power within an independently shielded case, focusing solely on the “sound conversion” task and providing an extremely quiet background.
Third is the device’s unique ‘Tone and Texture.’
A good DAC goes beyond simple one-dimensional restoration; it delivers a much richer, denser timbre through its hardware-specific chipset design and analog stage configuration. The ability to perfectly decode lossless high-resolution audio is a fundamental quality of Hi-Fi audio.
DACs, Amps, and Common Beginner Confusions
Recently, many portable “dongle” DACs used with smartphones have DACs and amps integrated onto a single board due to size constraints. Even mobile chipsets themselves are often designed as System-on-Chips (SoC) that combine both functions, leading beginners to mistakenly think that “a DAC is just an amp.”
However, to read spec sheets correctly, we must recognize that the audio engineering roles of a DAC and an amp are distinct. To put it simply, the DAC is the “brain” that interprets digital signals and gives instructions, while the amp is the “muscle” that receives that fine signal, physically amplifies it, and drives the speaker diaphragm.
For instance, the Cirrus Logic CS43131 chipset is a cost-effective integrated chipset with a built-in amp, making it advantageous for producing high output in a compact size. In contrast, its sibling, the CS43198, has the same DAC performance but separates the amp stage. This gives manufacturers the freedom to design a separate, high-performance amp circuit on the board outside the chipset.
(Left) Fiio. BTR13, (Right) Fiio KA15
Let’s compare Fiio products. The BTR13, which uses the CS43131, doesn’t mention a separate amp chipset. The KA15, which uses the CS43198, highlights that it “does not use the internal amp and adds a separate SGM8262 OP-AMP.” This means they have thoroughly separated the brain (DAC) from the muscle (AMP) to create a more specialized configuration.
The Gateway to Sound
To summarize the flow of audio signals: ‘Source file (data) → DAC (translation) → Amp (amplification) → Earphone (sound).’
In this audio chain, the DAC is the first point where cold 0s and 1s are resurrected into warm analog waves. The clarity and texture of the sound we hear ultimately depend on how that first step is taken. Perhaps it’s not just about making the sound louder, but our desire to feel even 1% more of the subtle reverberations and the atmosphere of the recording studio that leads us into the endless loop of “DAC-swapping.”
Part 2: Decoding DAC Specs (Preview)
Now that you know the DAC is the most vital gateway for establishing the pillars of sound, the complex numbers on spec sheets can still seem daunting when you’re shopping for new gear. In Part 2, I will patiently decode what those alien-looking numbers on spec sheets actually mean for your earphones.
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오디오 DAC 뜻이 뭐야? 이어폰 소리가 답답할 때 제일 먼저 사는 물건
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