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Hi friend and welcome!
How to choose a headphone amp is such a great question, and it comes up often. Many times we don’t really think about when or why we need one. We just sort of choose based on reviews, or what’s popular. Today I want to really dissect the process from start to finish, and hopefully give you some insight on different scenarios in which you may or may not need one!
So grab a snack, sit back and relax because..
You’ve come to the right place!!
What I will bring you in this guide
How to choose a headphone amp
Portable vs. Desktop
Output Impedance of the Amp
Sensitivity & Impedance
Some Amp recommendations
So without further ado, lets get started!
In your research for the best studio headphones for mixing, the best headphone under $500, etc. you probably came across an unexpected caveat: Needs proper amplification. Oh no! One of the things that discourages me most in my research is finding out that I have to do .. MORE RESEARCH! Lol.
Luckily for you, proper amplification doesn’t need to be such a chore. There are some really affordable, versatile, and quality options out there that consistently come up in reviews. Today I will attempt to concisely lay out some of my favorite options, inform you on when and how you should choose, as well as enlighten you on some of the most logical pairings.
How to Choose a headphone amp
It goes without saying that most of the low end models, ear buds, and generally sub-par offerings don’t need an amp at all. They are just meant to boost certain frequencies and provide a good listening experience for a low price. Sadly, most of the time they completely fail.
Have you ever purchased a $20 pair of headphones from CVS pharmacy and been utterly disappointed when you finally got home and put them on? Me too. It’s an unfortunate fact of life. These consumer grade cans are the worst of the worst. On the flip side, you may have been satisfied as well. I remember my very first Sony MDR V150’s. They were, and still are a pretty decent set, but the headband is famous for snapping under pressure. Sort of like Henry Hill in Goodfellas 😀
When you get into some of the decent entry level models, you still won’t need an amp. The Sennheiser HD 202’s are a similar price, but they are solid. They don’t need one. The Audio Technica ATH M50’s are an entry to mid-level pair, and they don’t need an amp either. Same goes with the Sennheiser HD 280’s.
Keep in mind: An audio interface, while not a headphone amp per se, does function as sort of an all around Amp/DAC for your studio monitors, microphone, headphones, etc. Just don’t purchase one specifically as a headphone amp. We’ll get into what a DAC is in a bit if you aren’t aware!
Portable vs. Desktop
The first question you should ask yourself is:
Do my headphones need an amp? The simplified answer: If the Impedance is High and/or The Sensitivity is low, you will probably need an amp. Learn more about Impedance:What is Headphone Impedance? There’s no concrete answer for “high”, but I would say anything over 100 Ohms needs more power. Even something under 100 Ohms may need it depending on the situation. The K701 and K702 are both great examples of headphones that have a low Sensitivity (around 91db/mW, not to be confused with the 105db/V that you often see listed), and need quite a bit of power to reach their peak. The thing to keep in mind is that most pairings will sound just fine. Don’t get too fancy about it. “If you wanna be fancy, hold your pinky out like this” As far as Sensitivity, anything around 97dB and lower generally needs more power from the Amp to reach optimal loudness (around 110dB is the standard). More on Sensitivity: What is Sensitivity in Headphones?
The second question is:
Do I need a portable amp or a desktop amp?
Obviously, if you spend a lot of time in an isolated studio or home environment, a desktop amp is essential.
What’s nice is that you could instead purchase a portable amp and it functions in the same way. You can leave it on your desk as you’re listening, or take it on the go. A perfect example is the Oppo HA-2 or FiiO E10K. It’s incredibly versatile and powerful. Learn more:Oppo HA2 Review!
The third question is:
Do I need a DAC? (Digital to Analog Converter)
Put simply, a DAC converts the 1’s and 0’s from your computer (the digital realm) into the analog sound that you hear, and vice versa. In recording, you scream obscenities (analog) into the microphone, and your computer makes sense out of it digitally for you to edit and EQ later. Learn more about this mind blowing process: Bit Depth vs. Sample Rate.
There’s also an internal DAC in your phone, mobile device, and pretty much anything that outputs sound. Your PC has an internal Soundcard that functions in the same way. What is a Soundcard?
All that said, only invest in a DAC if your Soundcard or existing DAC is poop. You’ll know because the sound will either:
Not be loud enough.
Sound like poop.
Make lots of unnecessary noise/crackling, etc.
For instance, my laptops internal Soundcard does not output at a listenable level. For me to achieve the volume that I’m looking for, some sort of DAC is required. The Amps/DACs that I’m currently demoing or own:
Schiit Magni/Modi (Own)
Oppo HA2 (Own)
FiiO E10K (Demoing)
JDS Labs cMoy bb (Demoing)
JDS Labs Element (Demoing)
JDS Labs Objective 2 (Demoing)
ifi iDSD Black Label (Demoing)
(Digital to analog converter)
What’s great about these is that they provide your headphones with a built in digital to analog converter + amp. Related:What is a USB DAC? The problem with computers is that the manufacturers rarely make audio a main concern. The result? An internal sound card that does a sub-par job of converting signal, and amplifying that signal to a listenable level (Discussed above). In recent years however, I would say it’s definitely gotten better. I use an old Lenovo T510 and I would never plug my headphones right into the 3.5mm jack. For folks with newer technology, an Amp/DAC may not even be needed! For me, an Amp/DAC is mandatory to get:
A) Loud enough volume
B) A quality digital to analog conversion
For instance, if I were to plug my headphones into the 3.5mm jack on the side of my laptop, I would be in for a world of pain like Smokey from The Big Lebowski (mark it 8 dude). Well, not so much a world of pain as a really bad listening experience. Noise, latency, interference, and low volume levels can run rampant here.
A good way to know is just try it out! If you’re not satisfied with the internal DAC on your various sources (PC/Laptop/Phone/Tablet), then a good separate Amp/DAC will definitely improve everything across the board.
You’re provided with an exceptional sound card (DAC) and amp at a reasonable price (in most cases). Be aware that some headphone amps can reach into the thousands. Today we’re going to focus on some entry to mid grade ones however.
The FiiO E10K to the right is a good example of a nice budget option. I’m really enjoying this amp right now actually with my Sennheiser HD600’s!
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Generally speaking, the better your DAC is, the more accurate the sound will be. This doesn’t necessarily mean the sound will be better, but the representation of that sound will be. If the source of your music is bad, then your sound will still be bad. But, if you’re playing music from a good source, a good DAC will improve upon all of the qualities of your music. A good DAC:
Takes care of the clarity of the sound.
The definition of the sound.
Takes care of noise.
Effectively interpolates gaps left in digital media.
A good example of a Standalone DAC that excels in all areas is the Cambridge Audio DAC Magic 100. It really is magic! I found the A/D conversion absolutely pristine, to the point of extreme excitement like Arnold when he relates the Gym pump to climaxing. 😛
If you plan to use it on the go, a lot of the portable models can also run off of battery power in addition to being plug and play USB!
As of late, the portable DAC craze seems to really be taking off. Maybe I had been out of the loop a few years back, but all sorts of brands continue to pop up, and now more than ever before it’s extremely affordable to invest in one.
A great example of a portable Amp/DAC combo is the Audioquest Dragonfly Red. This tiny Amp resembles a USB thumb drive, and effectively bypasses your crappy internal Soundcard. Just plug it into a USB port and you’re done homie!
You can also use it with your phone paired with the right adapter! Interested in learning more about this bite sized wonder?
These boys are pretty nifty as well, but are a little bulkier and are meant to be used in studio only. They sort of resemble audio interfaces actually. Well some do. The one above looks like a mini turntable!
The difference is they have a lot less knobs and buttons overall, as they aren’t meant for plugging anything else into (i.e. your mic or studio monitors). What are Studio Monitors?
Another big difference between this and a portable combo is that the DAC and Amp are both stand alone. So to hook them up, the set up would look something like:
Computer/laptop > DAC > Amp > Headphone.
This is a relatively simple way of illustrating it. Amps such as the Magni paired with the Modi DAC sort of “stack” on top of each-other.
They also need a digital to analog converter so that your brain can make sense out of the numbers. It functions much like an audio interface. Related:What does an Audio Interface Do? The sound is a jumbled mess until it is converted to a signal that we can process. This signal is meant to be of a much higher quality than your standard built in DAC that comes with your laptop or CPU (as previously discussed).
Here’s an infographic I did explaining how to hook up an Objective 2 from JDS Labs (Standalone) to a DAC and then to your PC.
So how does this relate to the headphones themselves? Let’s find out!
As an example, a headphone like the 300 Ohm HD600 requires 20mW of power to perform optimally. The Schiit Magni 2 provides 260mW of power into 300 Ohms. You can see why it’s such a valuable piece of equipment. It can effectively power nearly any headphone, and in reality provides much more than is needed in most cases. The newer Magni 3 provides 430mW into the same 300 Ohm load. Wow! That’s a bit of overkill, no?
The takeaway here is to simply make sure that thepower outputof the Amp in question is sufficient for the headphones Impedance.
You can do this by checking out the specifications of the amp, as most spec sheets will give a rundown of how much power each Ohm rating can receive. For the Magni 3, the list is as follows:
Maximum Power, 16 ohms: 3W RMS per channel
Maximum Power, 32 ohms: 2W RMS per channel
Maximum Power, 50 ohms: 1.3W RMS per channel
Maximum Power, 300 ohms: 430mW RMS per channel
Maximum Power, 600 ohms: 230mW RMS per channel
So the Magni 3 actually provides even more power than the 2. Awesome! (I still have the 2).
Output Impedance of the Amp
Another way to determine if your amp will suffice for the headphones in question is to check the output impedance of the amp. A good rule of thumb is to choose amps that have a number as close to zero as possible.
A simple formula is as follows:
Take the Impedance of the Headphone. In this case we’ll use the HD600, which is 300 Ohms.
Divide 300/8 to get 37.5.
Next, check the output impedance of the amp. We’ll use the Schiit Magni 3, which is less than 0.3 Ohms.
To ensure that the amp in question will work, make sure that the output impedance never exceeds the Headphone Impedance. In our case it doesn’t. 0.3 Ohms is astronomically less than 37.5. We’ve got a winner!
Why does the number 0 even matter?
Simply put, a number close to zero ensures that the amp will always deliver the same (or roughly the same) output into any load. This ensures that the amp is a consistent performer with a variety of headphones. More on this:What is Headphone Impedance?
Sensitivity & Impedance
Do these things even matter? Of course!
Impedance is a great indicator of how much your headphone will resist an electrical load from the amp. When you have a headphone with a high impedance, it’s basically saying, “I don’t WANNA play loud enough!” Lol. So what do we do? Cower away in the corner and hide? Nah homie. We slap those headphones in the face and make them receive power. Just make sure your amp has enough!
Sensitivity matters because it’s an indicator of the current ultimately making the diaphragm inside the driver move, resulting in sound. But Sensitivity is also critical because it indicates how much power will be required from the amp to drive any given headphone to adequate listening levels (discussed previously).
So the lower the Sensitivity of the headphone, the more power it will require from the Amp to reach loudness. The HD600’s at 97dB need 20mW to perform at their peak. A headphone with 105dB needs much less; about 2.5mW. Pretty big difference!
A lot of entry level closed back models have relatively low impedance ratings, and don’t need one, but can benefit from one. The Audio Technica ATH M50x is a good example.
In general, the higher the impedance, the more likely you will need an amp to raise the volume to a listenable level. Why? Because it needs more power.
less than 100 Ohm: An Amp is not mandatory, but depending on the headphone, could improve the sound a little or a lot.
greater than 100 Ohm: An Amp is highly recommended, if not outright mandatory for optimal listening.
What is impedance anyway?
To put it simply, there’s a lot of math involved when you really get down to it. And since I’m no Mathematician, we won’t talk about it. Lol. Here’s a video if you’re really interested. Don’t say I didn’t warn you 😛
Seriously though, impedance is simply the combined resistance and reactivity the headphones present to the amplifier as an electrical load.
High impedance cans: Need more power to reach an acceptable listening level. They often benefit from an amp.
Low impedance cans: They may require more current to lower the damping factor between the amp and headphones. Will be driven loud enough from your portable players. The quality of the sound may be dramatically improved with an amp. Just be aware though that pairing a very low impedance can or earbud with an amp is more susceptible to blow out in certain instances. In other words, you won’t even have to turn the dial past 9 or 10 o’clock in most cases.
Tube amp vs. Solid State
Some headphones like the H800 will sound better with tube amplification. Check out this article: Tube amp vs. Solid State for more information!
Some Amp recommendations
Rather than giving you a whole slew of different amps, I’m going to name off a few popular audiophile headphones and then give sort of a “great option” for each. Keep in mind that this is highly subjective, but we’re also dealing with entry level, as well as mid-fi gear. These are Amps/DACS that I’ve come across time and again as solid options. You won’t really need a high priced amp unless you have a high priced can on your hands!
Choosing a headphone amp isn’t really that complicated of a process. Don’t be overwhelmed by the countless Amps/DACS out there. The Schiit, JDS Labs, and FiiO brands will more than suffice for the majority of your higher impedance headphone models. The difficulty comes when you’re purchasing expensive headphones like the Sennheiser HD 800. A set like that is more than amp finicky. It has the potential to sound completely different from amp to amp! A scary thought indeed. Luckily a lot of these entry to mid level audiophile headphones do well with a lot of the same gear.
With that, I would say that the differences from amp to amp aren’t as astronomically large as some people like to claim. There are subtle differences, sure. But Choosing an Amp/DAC should never be a stressful process. Find out the Impedance and Sensitivity of your cans, look at the power output on the Amp, and then just go for it. One amp isn’t going to make your music sound that much better than another. The differences are just too subtle. Most companies use really good DAC chips so it’s not really a big deal.
I would say for most people, the Dragonfly Red from Audioquest is the most practical and pragmatic solution if you’re desiring a true upgrade in sound. You can pair it with your phone or use it with your laptop. It’s super portable and convenient, and the DAC chip inside is fantastic. It makes your music just sound better!
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.