Home Resources Beginners Guide: What is a USB DAC?

Beginners Guide: What is a USB DAC?

Today we'll explain what a DAC is, why it's important, and whether or not you need one.

by Stuart Charles Black
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This is part 10 in a series on various studio equipment, what it does, and how to choose!

  1. How to Choose Studio Headphones (Coming Soon!)
  2. How to Choose a Headphone Amp
  3. How to Choose a Microphone
  4. How to Choose a MIDI Keyboard
  5. How to Choose a Turntable (Coming Soon)
  6. What are Studio Monitors?
  7. What does an Audio Interface Do?
  8. What does an Audio Mixer do?
  9. What is a Soundcard?
  10. What is a USB DAC? (You are here)

Hey there friend, and Welcome aboard!!

So what is a USB DAC? Before we get into it, grab a snack, sit back, and relax because…

You’ve come to the right place!!

Today we’ll go over the following:

  • What a DAC is
  • Why it’s important
  • If you need one

and lots more.

So let’s dive in!


Introduction


One of the most confusing things as a headphone enthusiast, hobbyist, or even up-and-coming audiophile is the concept of a DAC.

If you’re new to this, it’s almost like a foreign language.

The kicker is that pretty much all digital devices that play music contain one.

For instance, A Soundcard is a DAC, but it’s called a Soundcard.

Most gamers and regular folks recognize this term, but oftentimes a Soundcard is found internally within the system itself (your PC/Phone for instance), while a DAC is typically a standalone unit and comes in many different shapes and sizes.

Hence the confusion.


What is a DAC?


Simply put, a DAC is a Digital to Analog Converter.

It converts the digital signal from your PC into the analog sound you hear.

Your computer understands this as binary language, in the form of 1s and 0s, which is a language that our brains cannot understand (we interpret sound via analog).

Regardless,

both Analog to Digital (ADC) and Digital to Analog (DAC) processes are basically always happening depending on what you’re doing.

  • If you’re listening to music, information is constantly being converted for you in real time (Digital to Analog).
  • If you’re recording your voice via a microphone, your computer is converting that analog signal into digital for the purposes of editing, EQ’ing, playback, etc. (Analog to Digital).

The way it does this is by prioritizing and then quantizing those digital 1s and 0s as individually separate values, at a fixed rate, and of a specified size.

For instance, a CD-quality FLAC file samples 16 bits of information at 44,100 times per second.

A higher resolution file such as 24-bit might be sampled 96,000 times per second, or 192,000.

It just depends on the specific file in question. 

What about DSD?

That’s an entirely different can of worms and beyond the scope of this article.

In any event,

Each piece of data contains parameters that are used in accurately reproducing the sound.

Your computer then copies the original values and plays them back in the same order and rate at which they were captured.

This essentially produces an exact replica of the sound.

Mind blown right?

So a computer basically uses a string of these binary digits to describe the information it receives.

Those same digits eventually form bits, which is where we get the term bit depth from.

The higher the bit depth, the more accurate and precise the recreation of the original sound will be.

A lower bit depth means more information gets lost, thus contributing to more of a sub-par sound.

The Nyquist-Shannon Theorem

The Nyquist-Shannon sampling theorem says that the upper magnitude of a piece of digital audio will top out at half the sample rate.

This means that a 96kHz file still only tops out at 48kHz.

A 24-bit recording can contain up to 16,777,216 individual values, while 16-bit only has around 65,536.

The lower the bit depth, the more information is lost.

In my experience, you can actually hear a clear difference between a 16-bit file and a 24-bit one which is why I typically shoot for 24-bit if I can.

The difference isn’t staggering, but you will likely notice it in some form or fashion.

In other words,

music may sound a bit cleaner, with less distortion and a better overall presentation.


Why is a DAC Important?


A DAC is important because it’s responsible for converting a digital signal into something we can actually hear!

As an example, my old Lenovo T510 had a really crappy internal DAC.

This basically means that if I were to simply plug a headphone in, I’m not going to have a good experience at all.

A lot of things can happen with a bad conversion:

  • Noise/Static
  • Interference
  • Low Volume Output
  • Generally Poor Sound

To prove my point, I did a test. I used the internal Soundcard on my laptop as a DAC.

I plugged an RCA to mini cable from the 3.5mm jack on the side into the back of my old Schiit Magni.

I aimed to see if amplifying the signal from the built-in Soundcard would result in a decent sound.

Short answer: It didn’t. Lol.

Not only was the sound poor, but from the Magni, I had to turn the gain switch on AND jack the volume all the way up just to hear anything.

You can see why investing in a good DAC is important.

My laptop’s poopy one didn’t do a good job of converting the signal at all.

This is what a dedicated DAC can accomplish for you.

It provides a clean conversion worthy of even having an amp.

The problem with older technology is that manufacturers rarely made audio the main concern.

Nowadays?

Times are much different. You may or may not even need an Amp + DAC depending on:

  • Your headphones in question, i.e. their Impedance and Sensitivity ratings.
  • The quality of your device’s internal DAC.

Fortunately, as technology has progressed, companies do tend to provide pretty good internal DACs on most equipment.

Speaking of,


Do You Need A DAC?

+ Headphones & Sensitivity


I’ve read online that some can’t even tell the difference between a dedicated Amp/DAC vs. just plugging their headphones into an iPhone.

Whether or not you invest in something separate depends entirely on your unique situation.

A good way to find out is to just try it!

I think a lot of people get caught up in wanting to buy something when they didn’t even properly evaluate the situation on their own.

If you plug a headphone into your phone and it doesn’t reach peak loudness (doesn’t sound acceptable to you), and/or it just plain sounds bad, then you probably need something more.

The standard for loudness is around 110 dB.

It’s monumentally important to know a couple of things about your headphones before purchasing a separate amp and DAC though, even if you do find your cans loud enough:

  1. The Headphone Impedance
  2. The Headphone Sensitivity

I did write separate articles on both (linked above), but I’ll condense them quickly for you.

The Impedance rating

This is the combined resistance and reactivity that your headphones present to the amp as an electrical load.

In layman’s terms, this just means how much they resist wanting to play loud enough.

The higher the number, the more they resist.

This is why it’s important to have an amp that provides an adequate amount of power for both their Impedance level and Sensitivity rating.

Sensitivity

This is a measure of how efficient the headphone is at using the power it receives.

  • If you have a headphone with low Sensitivity, it’s less efficient and will need more power from the amp.
  • If you have a headphone with High Sensitivity, it’s more efficient and will need less power from the amp.

Generally speaking, anything above 100dB is considered high, and anything around 97dB and lower is not very efficient.

An HD600 is a good example of a headphone that needs some power @97dB Sensitivity and 300 Ohms Impedance.

That’s a relatively simple way of looking at it.

In many instances, the Sensitivity number may actually be a better indicator of whether or not you need an Amp/DAC.

Why?

Because efficiency is typically a better indicator of how much power is required.

  • Lower Sensitivity (97dB and lower) = Not very efficient. Absolutely plan on purchasing an Amp/DAC.
  • Higher Sensitivity (100dB and up) = You probably won’t need one, however: it may help sound quality depending on which one you go with.
  • If you have a headphone with 98dB or 99dB, look at the Impedance. If the Impedance is below 100, you can probably scrape by without an amp. Every case is different though, and this isn’t set in stone. You’ll just have to experiment. 🙂

Video Discussion

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Final Word


Need some help with how to go about all of this?

Learn More:

 

Well, that’s about it for today folks! I hope you’ve come away with some valuable insight about this fully loaded question, What is a USB DAC?

Did I answer your question? Do you need any further clarification on anything? Let me know!!

Questions? Comments? Requests? Did I miss the mark on something? Let me know in the comments below or Contact me!! I would love to hear from you…

Until then, all the best and God bless…

 

 

-Stu

[Xtr@Ba$eHitZ]

Can’t decide which headphones to purchase? Interested in a complete buyers guide outlining over 40 of the best options on the market? Click on over to the best audiophile headphones to learn more!!

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