What is a headphone AMP?

[PCTechNoob]

So I've been looking at headphones for a few months now, and have found the beyerdynamic DT 770 PRO which seem great for what I'm looking for.

I'm not an "audiophile" just looking for a good all-around pair of headphones that are comfy, high quality and can be used in a variety of situations, however I've heard that this pair requires an Amp / Headphone Amp / Pre-Amp (whatever it's called) to function properly with my PC. So I'm just wondering what the difference is from just plugging them directly into the motherboard via the headphone jack in the front of my PC case opposed to a separate Amp, and how my current $30 Sony headphones work fine but the beyerdynamic needs an additional device thingy?
And also if anyone has any recommendations for a cheap Amp thing I could use, as I don't want to have to spend the same again just to plug in my headphones, otherwise I'll have to keep looking at other brands and models. Thanks for any help!

[Guest]

Headphones can get crazy. AMPs, DACs, etc can get very complicated and expensive, very quickly. Some headphones require more power than others to drive.

I'll leave it to more knowledgeable audiophile to make recommendations.

[Oshino Shinobu]

Depends on the model of headphones really. The higher the impedance (measured and quoted in Ohms), the more power that's needed to drive them. BeyerDynamics DT series often have multiple versions with different impedance ratings. If you want a good pair for general use and not just for sitting at your PC, you'll want to go with a lower impedance rating so things like your phone can drive them okay. 

 

A headphone amp is an amplifier. It makes the signal "louder". They're not required, but if you run high impedance headphones on a weak audio source, it won't get very loud. An amp will amplify the signal and allow you to make it louder. A weak/cheap audio source may be able to get the signal loud, but it may end up distorting when doing that. A dedicated and good amp will let you increase the volume without it distorting (provided the headphones can handle it). 

 

I'd personally recommend something like the Sennheiser Momentum 2.0s or AudoTechnica MSR7s for good general purpose headphones. Both get plenty loud off a phone. 

[Mooshi]

From personal experience, even high quality audio on expensive motherboards don't sound as nice as a budget usb dac/amp for $99 dollars.

[Dackzy]

20 minutes ago, Oshino Shinobu said:

The higher the impedance (measured and quoted in Ohms), the more power that's needed to drive them.  

that is just wrong, plain wrong. The impedance basically matters 0 when it comes to how much power a headphone needs. Now that you mention the DT series, I can use them as a exsample. All of the versions of let's say DT 770 have the same sensitivity rating of 96dB/mW, which means no matter what version you buy they need 1mW to reach 96dB.

The difference is the amount of voltage and amperage. 

 

So now an example

To reach 85dB the 80 ohm version of the DT 770 needs 0.08V and 1mA which is 0.08mW

To reach 85dB the 300 ohm version of the DT 770 needs 0.15-0.16V and 0.5mA which is 0.08mW

 

The best way too look at impedance is really like a voltage divider.

 

Where the misconception hits is probably that the power of a lot of amps goes down when the impedance goes up, BUT there we have OTL type amps where they actually have more power at a high impedance than at a low impedance.

 

For OP I would just test with what you have.

[SpaceGhostC2C]

You will find some motherboards come with a "headphone amp" feeding a particular audio port to service this kind of headphones¹

 

 

¹Don't take it as a promise that this particular model will work with certain motherboards, it's a generic comment