How to Know if You Need a Headphone Amp

Explanation

If you lot've developed an interest in what is known as "personal audio" and have already invested in a decent pair of headphones, information technology's quite likely that y'all may accept wondered nearly amplification. Specifically, what we're talking virtually today is whether or non you will experience whatsoever observable benefit from using a dedicated headphone amp to bulldoze your prized cans.

You but demand an amplifier when your source'due south maximum electrical output through the headphone jack—whether it'southward a smartphone, laptop, or something else—is lower than what your headphones require to accomplish the output level yous want. Bluetooth headphones will never need an amplifier, as the headphones themselves deliver the power to the drivers internally.

Editor's notation: this article was updated on June 14, 2021, to expand upon technical information.

Why would you need a headphone amp?

If and just if you're using wired headphones, go plug them into whatever y'all're going to be listening to them with. Can you get the volume up to a good level? Is at that place room to spare?

If you answered "yep": Congratulations! You don'tneed an amplifier. An amplifier's chore is to increase the power output of your source to the level you lot want, and if whatever you're using to heed to music can do that on its ain: a lack of power isn't one of your bug. You can stop reading here and go bask your audio adventures! If your audio sounds bad, it'due south due to something else.

If you answered "no": Buckle in kiddo, we've got some math to go over.

When you crank your volume on your smartphone only can't get an acceptable listening level, there'due south a few things that could be happening.

1. You lot've gone and done it: you cooked your ears and now you're difficult of hearing
2. Your headphones are cleaved
3. Your source tin can't satisfy the ability requirements of the headphones

The first item on that list can't be solved, just thankfully it's the least likely scenario. The solution to the tertiary problem is an amplifier.

I need you to get to the specs page of whatever headphones you've got (or are planning to buy) and take down a couple of numbers for me. Got a pen and newspaper? Write down the impedanceand the sensitivity of your cans. Impedance is the ability of your headphones to resist electric current, and the sensitivity refers to how loud they'll get with one milliwatt of power. If your eyes just glazed over, don't worry: it's not just yous, this can be tedious. All we're doing here is but trying to figure out if whatever you're using to play music on tin can become whatsoever ability the headphones you need to reach your normal listening volume.

Specs pages can be wearisome, merely they are useful if you're wondering if you need an amplifier.

These numbers will be able to definitively tell you whether or not you need an amp with your source, but it takes a footling bit of math. If you're different me (and you have a life), you lotcould use this tool and be washed with it… but wouldn't you like to at to the lowest degree understand what'south going on?

Plumbing metaphors and electricity

And then in guild to get enough juice to your headphones, your source needs to be able to handle the chore. In that location are several factors working against you lot, including the headphones' innate tendency to resist electricity, their power requirements, and so on.

Electrical circuits are a lot like a h2o system. When you think of "current," call back of the rate water flows through the pipes. When you lot see "voltage," think "water pressure," and when you read "impedance," recall about how narrow the pipes are (which constricts the flow of water a certain amount). It's not a perfect analogy, but it works for what we're talking nigh. When yous want to pump a certain corporeality of h2o out of a reservoir, you'll need to know the previously mentioned things to decide what it'll take to go it.

Flickr user rheinitz Despite the metaphor, delight resist the temptation to plug your headphones into a spigot.

For headphones, you demand to have at least that corporeality of "water" at all times in club to work properly. While you lot might be okay waiting for a minute or two while you fill up a saucepan at a hand pump, your headphones can't wait for the right amount of power to build up.

That's where an amplifier comes in. Using its own power (or reservoir, if we're going to continue this analogy), it can heave the signal from a source to satisfy the headphones' requirements.

What is the decibel scale?

Editor's notation: This is gonna get really dry and textbooky then if you just want some common examples, skip to the concluding 2 paragraphs of this section

Do you know what a decibel (dB) is? It'south okay if you don't, we're only talking broad strokes hither. It'south merely a ratio of two values, ane existence the reference. The dB scale is logarithmic, like our hearing; every time yous increment the power by 10dB, you're increasing the power output in watts 10 times over. A 100dB indicate is ten times more than powerful than a 90dB one, and 100 times as powerful as an 80dB signal. While the perception of loudness can't be measured considerately, nosotros do know that humans perceive a change in 10dB to exist a change of roughly 2x in loudness. 70dB is twice every bit loud as 60dB, four times every bit loud as 50dB… y'all go the idea. If you're wondering what level you should be targeting when y'all make your calculations, I usually say 85dB merely because it's loud, just non so loud as to requite yous noise-induced hearing loss that quickly.

Flickr user mujitra Portable amps are still clunky, so buying headphones that work well without one is a smart purchase.

And so remember when I told you to write downwardly that sensitivity number? That's how loud the headphones volition get when in that location's one milliwatt of electric current practical to information technology; usually, this is pretty loud—a level you shouldn't be listening to anyhow—but it's how we decide the baseline for figuring out how much more than power needs to be applied to enhance or lower the volume. By using Ohm's law and applying what we know virtually decibels, we tin can figure out the electric current needed to become a sure volume level.

Related: Types and signs of hearing loss

Substantially, the math works like this: for every 10dB you want to increase the volume, you lot need to use 10 times the power. For every 10 dB y'all want to decrease the volume, you demand to reduce it to i/10th the power. Easy enough, merely what about the voltage? Basically, it's as piece of cake equally plugging your numbers into this equation: Voltage(Vrms)=√[Power in Watts*Impedance]. Just remember, because we're dealing withmilliWatts, be sure to split up whatever number in front of mW by 1000 starting time.

Centers for Affliction Control The CDC and Chris Thomas concur, continue your tunes lower than 85dB.

Permit's look at two dissimilar theoretical examples. Headphone A has an impedance of 300Ω and a sensitivity of 85dB/mW. While it only needs 1mW at 0.55Vrms to reach a comfortable listening book of 85dB, in order to increase the level on your hifi setup you'd need to pump 10mW at one.73Vrms to reach 95dB. That's a lot of juice, and not something your smartphone tin really exercise. Given that a smartphone can't output that kind of power, you lot're going to want to utilize an amp with headphone A.

Alternatively, Headphone B was designed for smartphones and has an impedance of 32Ω and a sensitivity of 105dB/mW. This fix will but demand 0.01mW at 0.02Vrms to reach 85dB, and will be much easier to run off of just well-nigh whatever source because it is so efficient. You lot will set your headphones on fire and deafen anybody around you long earlier you'd reach power levels that would require an amplifier with Headphone B.

Simply what most cables?

Who volition win, the coathanger, or the well-engineered consumer cables?

If you find yourself asking "only what about cables? If they're too small, wouldn't that make a departure?"—you'd be correct! However, the vast majority of all cables available to you will be more than sufficient to support what you demand. This is especially true for headphones, which typically have much lower ability requirements, and also shorter cables, than speakers practise.

We've covered issues regarding cablevision quality and specs before, and you should definitely read up on it! If nothing else, the coat hanger cable experiment is entertaining, and demonstrative of the fact that you don't need to shell out for expensive cables to get stone-solid audio quality. High-quality materials and interconnects are onlyneeded if you're planning on exposing them to the elements. If you're staying indoors in a climate-controlled room? Go ahead: cheap out on cables.

Then, do y'all ever need a headphone amp?

If it wasn't obvious before, very few headphones out there require a lot of juice to work properly. It'due south really merely when you start getting into the world of audiophile-course cans that you start to encounter models that require a dedicated amplifier to piece of work the style their designers intended, and that's because most headphones—fifty-fifty the newer high-end ones—are being designed for use with things like iPods, smartphones, and Bluetooth; low-power devices.

Read next: Best headphone amps

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Source: https://www.soundguys.com/do-you-need-an-amp-12561/