How Do You Know if an Amp Ccan Drive Your Headphone

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If you've developed an interest in what is known as "personal audio" and accept already invested in a decent pair of headphones, information technology'due south quite likely that you may take wondered most distension. Specifically, what we're talking nigh today is whether or non yous will experience whatever appreciable do good from using a defended headphone amp to bulldoze your prized cans.

You merely need an amplifier when your source's maximum electrical output through the headphone jack—whether information technology's a smartphone, laptop, or something else—is lower than what your headphones require to reach the output level you want. Bluetooth headphones will never need an amplifier, equally the headphones themselves deliver the power to the drivers internally.

Editor'south note: this article was updated on June fourteen, 2021, to aggrandize upon technical information.

Why would you need a headphone amp?

If and only if you lot're using wired headphones, go plug them into whatever you're going to be listening to them with. Tin can you lot get the volume upward to a good level? Is at that place room to spare?

If you answered "aye": Congratulations! You don'tdemand an amplifier. An amplifier's job is to increase the power output of your source to the level you desire, and if any you're using to listen to music can do that on its ain: a lack of ability isn't ane of your issues. You can stop reading here and go savour your audio adventures! If your audio sounds bad, it's due to something else.

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

When yous crank your volume on your smartphone but can't get an acceptable listening level, there'south a few things that could exist happening.

1. You've gone and done it: you cooked your ears and at present you're hard of hearing
2. Your headphones are broken
3. Your source tin can't satisfy the power requirements of the headphones

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

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

Specs pages can be boring, but they are useful if you're wondering if you lot demand an amplifier.

These numbers will exist able to definitively tell you lot whether or non yous need an amp with your source, just information technology takes a little bit of math. If you lot're unlike me (and you take a life), you lotcould use this tool and exist done with it… but wouldn't you similar to at to the lowest degree sympathize what'southward going on?

Plumbing metaphors and electricity

So in society to become enough juice to your headphones, your source needs to exist able to handle the job. At that place are several factors working confronting you, including the headphones' innate tendency to resist electricity, their power requirements, and so on.

Electric circuits are a lot similar a water system. When you think of "current," think of the rate water flows through the pipes. When you lot encounter "voltage," call back "water pressure," and when y'all read "impedance," think about how narrow the pipes are (which constricts the flow of water a certain corporeality). It's non a perfect analogy, but it works for what we're talking most. When you want to pump a certain amount of water out of a reservoir, you lot'll need to know the previously mentioned things to determine what it'll take to get it.

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

For headphones, you lot need to have at least that amount of "water" at all times in order to piece of work properly. While you lot might be okay waiting for a minute or 2 while y'all fill up upward a saucepan at a hand pump, your headphones can't wait for the right amount of ability to build up.

That'south where an amplifier comes in. Using its own power (or reservoir, if we're going to go on this illustration), 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 actually dry and textbooky so if y'all merely want some mutual examples, skip to the last 2 paragraphs of this section

Do you know what a decibel (dB) is? It'south okay if you don't, we're only talking wide strokes here. Information technology's simply a ratio of two values, 1 beingness the reference. The dB scale is logarithmic, like our hearing; every time y'all increase the power past 10dB, yous're increasing the power output in watts 10 times over. A 100dB betoken is ten times more powerful than a 90dB one, and 100 times every bit powerful as an 80dB signal. While the perception of loudness can't be measured considerately, we do know that humans perceive a change in 10dB to be a change of roughly 2x in loudness. 70dB is twice every bit loud as 60dB, four times as loud equally 50dB… you get the idea. If you're wondering what level you should exist targeting when you lot make your calculations, I usually say 85dB only considering it's loud, just non so loud as to give you racket-induced hearing loss that quickly.

Flickr user mujitra Portable amps are nonetheless clunky, so ownership headphones that work well without 1 is a smart purchase.

So call up when I told you to write down that sensitivity number? That's how loud the headphones will get when at that place'southward i milliwatt of current applied to it; usually, this is pretty loud—a level you shouldn't be listening to anyway—but it's how we make up one's mind the baseline for figuring out how much more than power needs to be applied to raise or lower the volume. Past using Ohm'south law and applying what we know almost decibels, we can figure out the current needed to get a certain volume level.

Related: Types and signs of hearing loss

Essentially, the math works similar this: for every 10dB you desire to increase the volume, you need to use ten times the power. For every 10 dB you lot want to decrease the volume, you lot demand to reduce it to one/10th the power. Easy enough, but what almost the voltage? Basically, it's every bit like shooting fish in a barrel as plugging your numbers into this equation: Voltage(Vrms)=√[Ability in Watts*Impedance]. But remember, because nosotros're dealing withmilliWatts, be sure to carve up any number in front of mW by 1000 showtime.

Let's look at 2 different 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 comfy listening volume of 85dB, in order to increase the level on your hifi setup you'd need to pump 10mW at 1.73Vrms to reach 95dB. That's a lot of juice, and not something your smartphone can really do. Given that a smartphone can't output that kind of ability, y'all're going to want to utilise 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 prepare will only need 0.01mW at 0.02Vrms to reach 85dB, and will exist much easier to run off of simply most any source because information technology is and so efficient. You will set your headphones on burn and deafen everyone around you long before you'd reach power levels that would require an amplifier with Headphone B.

But what about cables?

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

If you detect yourself asking "simply what about cables? If they're too small, wouldn't that make a difference?"—you'd be right! However, the vast bulk of all cables bachelor to you volition be more than sufficient to support what yous need. This is especially truthful for headphones, which typically accept much lower power requirements, and besides shorter cables, than speakers do.

We've covered issues regarding cable quality and specs earlier, and you should definitely read up on information technology! If naught else, the glaze hanger cable experiment is entertaining, and demonstrative of the fact that y'all don't need to shell out for expensive cables to get rock-solid audio quality. High-quality materials and interconnects are onlyneeded if y'all're planning on exposing them to the elements. If you're staying indoors in a climate-controlled room? Go ahead: cheap out on cables.

So, practise you ever need a headphone amp?

If information technology wasn't obvious before, very few headphones out in that location require a lot of juice to piece of work properly. It'due south actually only when you showtime getting into the globe of audiophile-class cans that you kickoff to see models that crave a defended amplifier to work the way their designers intended, and that's because most headphones—even the newer high-end ones—are being designed for employ with things like iPods, smartphones, and Bluetooth; depression-ability devices.

Read next: Best headphone amps

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

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