What is a USB DAC? | EVERYTHING YOU SHOULD KNOW!!
Updated 11/10/18
3,279 word post, approx. 7-8 min. read
This is part 5 in a series on Headphone Specs, Drivers, DACs, Sound, and how all of them relate to each other. There’s a wealth of knowledge in these so don’t hesitate to open some more tabs, bookmark, and share!!
- What is Headphone Impedance?
- What is Sensitivity in Headphones?
- What is a Headphone Driver?
- What is a Planar Magnetic Driver?
- What is a USB DAC? (This Article)
- What is Soundstage?
- What is Latency?
- What is Timbre?
- What is MIDI?
- What is XLR?
- What is SPL?
- What does Sibilant mean?
- What is the Sennheiser Veil?
- Do Headphones Need to be Burned In?
- How Do Noise Cancelling Headphones Work?
Hey there friend, and Welcome aboard!!
So what is a USB Amp DAC? Before we get into it, grab a snack, sit back and relax because..
You’ve come to the right place!!
What I will bring you in this article
It is my goal for this and every article I write to be as detailed and thorough as I possibly can about what I know. Today’s assessment will attempt to dissect the entire question from A-Z and leave nothing out. By the time you’re finished, you should have a good understanding of What a DAC is, why it’s important, and if you should even purchase one in the first place!
Think of this as an informative article/buying guide. It will ebb and flow with the times!
We’ll also cover what an amp does, but that’s less important overall than the concept of a DAC. Hang tight!
Table of Contents
Introduction
What is a DAC?
Why is a DAC Important?
Do you need a DAC?
What is an Amp?
Amps, DACs, Combos, and everything in between
Some Great Amp/DAC Combos
Great Standalone Amps
Great Standalone DACs
Hooking it Up
Final Word
Now without further ado, let’s get rolling!
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 problem with the audiophile world is that people rarely explain things in a way that makes any sense. This is just my opinion, stemming from years and years of reading forums, articles, reviews, and anything in between. When I read something, I want it organized and concise. Lots of bullet points, etc. Just lay it out in a way that logically appeals to my senses, and doesn’t leave me feeling like I need to clean my house. Have you ever felt like you were so discombobulated in your mind and the only remedy was to clean things and get organized? That’s me for sure. Once everything is in place, then I can focus better. It’s the same way when you’re reading something.
The person knows what they’re talking about, but if their but their methodology is messy it just can’t work. Either they all just expect you to know everything already, or they’ll explain it in a vague way and leave out important details and concepts that the average person can understand.
Technical jargon, while great for nerds and engineers, does nothing for the person that truly wants to understand what’s going on in a simplistic manner. This is where I come in. To truly understand a concept, you have to break it down and get to the root of what’s actually happening. Today we’ll do just that!
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 that you hear. Your computer understands this as binary language, in the form of 1’s and 0’s.
These two 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.
- If you’re recording your voice, your computer is converting the analog signal into digital for the purposes of editing, EQ’ing, playing back, etc.
The way it does this is by prioritizing and then quantizing those digital 1’s and 0’s as individually separate values, at a fixed rate and of a specified size. 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. Related: Bit Depth vs. Sample Rate.
A lower bit depth means more information gets lost, thus contributing to more of a sub-par sound.
The Nyquist-Shannon Theorem
In recording, 24bit/96kHz is just about the most you’ll ever want or need. Why? Because Science!
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 even at 96kHz, you’ll still only be receiving 48. Considering the average human can’t even hear 20kHz, sample rate numbers are bit overrated.
I would say bit depth is much more important. A 24-bit recording can contain up to 16,777,216 individual values, while 16 bit only has around 65,536. This actually makes more of a difference considering what we touched on above. The lower the bit depth, the more information is lost. It’s really that simple!
In my experience, you can actually hear a clear difference between a 16-bit file and a 24-bit one. It’s not staggering, but it’s going to make a difference to you. You’ll be much more excited about listening to 24-bit recordings with a good set of headphones and an amp proper. It’s borderline magical with a headphone like the Focal Utopia. Learn more: Focal Utopia Review!
So, now that we actually know what a DAC is, let’s find out why it’s important!
Why is a DAC Important?
A DAC is important because it’s responsible for converting a digital signal into something we can actually hear! A lot of people like to inadvertently place more emphasis on the Amp, but the DAC is what actually matters.
We’ll get into amps in a bit though..
As an example, my Lenovo T510 has a 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 Schiit Magni. My goal was to see if amplifying the signal from the built in Soundcard would result in a decent sound. What is a Soundcard?
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 laptops 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 a main concern.
Nowadays times are much different. You may or may not even need an Amp + DAC depending on:
- Your headphones in question.
- The quality of your devices internal DAC.
Fortunately, as technology has progressed, companies do tend to provide pretty good internal DACs on most equipment. My LG-X charge has a decent one, but I’d still prefer having a separate Amp/DAC like the Audioquest Dragonfly Red. More on that later!
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 on their own. If you plug a headphone into your phone and it doesn’t reach peak loudness (doesn’t sound acceptable to you), then you probably need something more. The standard for loudness is around 110dB.
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.
- The Headphone Impedance
- The Headphone Sensitivity
I did write separate articles on both, but I’ll condense it down quickly for you. Make sure to check those out as well for a more in depth look!
- The Impedance rating is simply 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 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 power @97dB and 300 Ohms.
That’s a relatively simple way of looking at it. In most cases, the Sensitivity number is much more important than a headphones Impedance. What you really want to know is how efficient the headphone in question is. That will allow you to gauge whether or not you’ll need a separate Amp and DAC.
- Lower Sensitivity (97dB and lower) = 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. 🙂
What is an Amp?
and how it relates to the DAC
All an amp does is amplify that signal from the DAC to a listenable level.
You can see why having an amp and a poor DAC is essentially useless from my example above. All I was doing was amplifying a bad conversion from my laptops internal DAC/Soundcard.
Fortunately for us, the differences in standalone DACs are fairly marginal and just about every dedicated DAC that I’ve had experience with sounded marvelous.
That said, you really can’t have one without the other. In that sense both become monumentally important.
So you may be wondering what your options are at this point, and how you may hook everything up.
Amps, DACs & Combos
And everything in between
There are 2 options you have when deciding:
- An Amp/DAC Combo. This has both built into one.
- A separate Amp + separate DAC. This will require some extra cables. We’ll get into that soon.
First we’ll talk about a USB DAC, which in most cases comes with an amplifier integrated. Essentially it’s a combo. You won’t have to worry about different wiring and the like. All Amp/DAC combo’s that I’ve demoed come with at least a USB cable to hook up to your computer.
A cable is really all you’ll need! Do be aware that in some cases you may have to go to the companies website for a driver download. No big deal.
For instance, I just received the iDSD Black Label from ifi for demo. When I plugged it into my laptop the device was not recognized. Normally it is. It would have been nice of them to specify that a driver download was needed, but I digress.
With 99% of Amp/DACs, you won’t have an issue. For the iDSD, I simply went to ifi’s website and downloaded the latest driver for my PC. After that it worked like a charm!
In some cases, you won’t ever need a driver at all!
The Audioengine D1 is a great example of an Amp/DAC combo that is truly plug and play and doesn’t need a driver. Ever. If that wasn’t reason enough to purchase one, well:
- It also comes with an Optical/Toslink input for Gaming consoles.
- It has RCA/Analog outs for hook up to your Studio Monitors. What are studio monitors?
- It has USB input for hook up to your PC/Laptop.
Pretty much an all purpose tool! You can use it to power monitors, listen to music, or game from your console/PC. I got a chance to demo one and fell in love with it. Learn more: Audioengine D1 Review | MOST VERSATILE AMP/DAC?
What’s cool about some USB Amp/DACs is that they can also function as just a DAC.
For instance:
You can run an RCA to mini from something like a FiiO E10K to the back of the Magni. Just plug the 3.5mm end into the line out of the E10K, and plug the male ends into the back of the Magni.
Voila! The E10K, while also an amp, now functions as a DAC. Just turn the volume knob to power it on, and then use the Magni as your actual amp.
It’s always nice to have both the amp and DAC in one because it basically means there’s no having to figure out which wires you’ll need.
Let’s take a look at some good combos!
Recommended Amp/DAC Combos
All of these have USB input!
We touched on a couple above, but here are some of my favorites:
- Budget – FiiO E10K. Provides a total of 200mW of power. Will still power an HD600/650 with relative ease. Anything with a Sensitivity below 97dB is not recommended with this amp. There simply won’t be enough juice. Learn more: FiiO E10K USB DAC Review!
- Step up – Audioquest Dragonfly Red. This is probably my favorite overall piece of equipment as it’s super convenient and fits anywhere. Like the cMoy, you can use it with your phone, but it does need an adapter. Still, I find it more compact than the cMoy as it’s smaller and less cumbersome. Learn more: Audioquest Dragonfly Red Review
- Most Versatile – Audioengine D1. We talked a bit about this briefly. Probably my favorite all around piece that can be used in a variety of different ways. Highly recommended for Gaming! Learn more: Audioengine D1 Review
- Another Step Up – JDS Labs Element. This runs around $350 and sounds pristine. I love the fact that it resembles a small turntable. It looks unique and is extremely powerful as well, powering most any headphone out there. Learn more: JDS Labs Element Review
- End Game – Chord Mojo. For me this is about the ceiling for quality, and the most anyone would ever need as far as Amp/DAC combos are concerned. This is by far the best one I’ve heard, and it really does make your music sound better than any of the aforementioned models. Can’t say enough good things about it. Learn more: Chord Mojo DAC Review!
Let’s talk about standalone amps!
Great Standalone Amps
JDS Labs Objective 2.
- Standalone on JDS’ Website: Check Here!
- Combo with the ODAC: Check Here!
- Price of Standalone Amp: Check Amazon!
- Combo with the ODAC: Check Amazon!
A perfect desktop solution, with a ton of power and a small footprint. It has a clean, crisp sound that will improve Soundstage on your headphones as well. What is Soundstage?
LEARN MORE IN MY OFFICIAL JDS LABS OBJECTIVE 2 REVIEW!!
Schiit Magni 3.
I still have the 2, but there’s not a whole lot of difference between them. The 3 does provide more power, but in reality it didn’t really need anymore. For clarity’s sake, the Magni 3 outputs 430mW into 300 Ohms vs. 260mW for the Magni 2. A Sennheiser HD600 at 97dB only needs 20mW to perform at peak loudness. So as you can see, a bit of overkill. Even so, I suppose if you had a really expensive headphone that needed a lot more power, the Magni 3 would be great. The problem is that most regular folks won’t ever need 430mW for anything other than a prick contest. Haha. Still a great amp. Clean, neutral, etc.
What about great Standalone DACs?
Great Standalone DACs
Great DACs are a dime a dozen. I wouldn’t worry too much about which you go with. The difference between a $100 DAC and a $200 one is pretty much negligible. I did find that the Cambridge Audio DAC Magic 100 seemed a bit cleaner than something like a Modi, but it could entirely be my imagination.
Here are a few good ones that you should keep in mind:
- Schiit Modi. Pairs well with the Magni as well as the Objective 2. These are the cables you’ll need if you want to pair it with an Objective. If you want to pair it with a Magni, you’ll need these cables.
- JDS Labs OLDAC. This is the pairing you should use if you plan on getting an Objective 2. It comes as standalone or you can purchase the combo. You can also buy the OLDAC with optical for Gaming purposes.
- Cambridge Audio DAC Magic 100. This is a great all around option, as it has RCA/Analog, USB, Optical/Toslink, and S/PDIF. Extremely versatile and sounds amazing!
Check out some graphics on how to hook it up!
Hooking Up an Amp + DAC
Graphics courtesy of Home Studio Basics (Me). Please share!
Just sub out the RCA to mini for an RCA to RCA for something like a Magni. The Objective 2 utilizes line output.
Final Word
Here’s a table of all the Amp/DAC combos we discussed today (I could not find the Element on Amazon). My personal recommendation for most people would be the Dragonfly Red. An incredible investment!
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
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!!
Be sure to also check out my Reviews and Resources page for more helpful and informative articles!
About The Author
Stuart Charles Black
Stu is determined to provide the truth about all things audio, and strives to deliver excellent content to you the reader! In his spare time, he likes to fish, paint, play guitar, attend church, take photos, record videos, graphic design, and more. His attention to detail and perfectionist attitude are what allow him to excel, but it can be both a blessing and a hindrance at times.