What is typical notebook/laptop headphone jack power rating?

Question

I recently got a Sennheiser HD201 Headphones. I am not sure to whether my laptop is good enough to drive these headphones. I have an Acer V5-131 laptop with Realtek audio.

I don't like my music loud. With my sony in ear style earphones I only listen at 40-50% volume both in player and on laptop volume. But with my new headphones I have to turn up volume 100%(both player and laptop) to reach decent audible levels. I feel like audio is getting distorted as well because of this. would an amp help here? I am not a expert but, will audio get distorted at 100% volume?

I checked out some amplifiers like FiiO E6 which outputs about 100-150mw to my HD201 which is 24 Ohms. So before getting an amplifier I want to know what my laptops headphone jack is capable of. I want to know what is typical power rating for laptop/notebook headphone jack?

EDIT:

From this link which is really useful and quite comprehensive, I calculated required power for my headphones for decent audible level without any distortion.

For 110db SPL which is about 30db average. Antilog ( ( 110 – 108) / 20 ) = 1.25V RMS 108 db/1V RMS is my headphone sensitivity

Now coming to power requirement ( V * V ) / Impedance = (1.25 * 1.25)/24 ohm = 65mW

I looked up further. My laptop is using Realtek ALC269 chip. I checked datasheet as well. Line voltage is 1.5v RMS MAX (this can drop significantly based on load and current limiting). But there is no max current limit provided there (or I couldn't read datasheet properly) so I could not calculate max output power.

Solution

From wikipedia:

Most headphone amplifiers provide power between 10 mW and 2 W depending on the specific headphone being used and the design of the amplifier. Certain high power designs can provide up to 6W of power into low impedance loads, although the benefit of such power output with headphones is unclear, as the few orthodynamic headphones that have sufficiently low sensitivities to function with such power levels will reach dangerously high volume levels with such amplifiers.

Also, be very careful. You are likely to get the headphones and the amplifier burnt if you don't know what you're doing.

As for the laptop jack output, it really depends on whether the jack is set to line-level output (around 0.15V) or headphone-level output (usually 0.5v), although it could reach 1v in some cases.

You should be able to find the tech docs for the audio codec of your laptop. For example, my dell has a conexant codec.

Comments

[James P]

Make sure the jack is set to headphone level and not line-out level as otherwise the sound level will be too low. Do you have Realtek drivers installed? They come with a control panel - it normally shows as a red speaker icon in the system tray on Windows. If you go to the Realtek control panel, it should show you the colour-coded jacks that are present on the laptop. If you double-click the green one it should give you the ability to choose the device connected.

[James P]

OK, but some laptops have three jacks, particularly if they have S/PDIF. The same thing should still work though. Do you have the Realtek Audio Manager installed?

[Sai Gadde]

My laptop has Realtek audio. I have drivers but it does not have any Audio manager. I can check and install Audio manager but how would it help in this case?

[James P]

As I mentioned in my first comment, it could be that the audio jack thinks you have speakers plugged in and has not boosted the output to a level suitable for headphones. The Audio Manager allows you to manually set which device is connected.

[Sai Gadde]

My question was about what power can a laptop provide. I can always look power output for amplifiers on manufacturer or product page. But my laptop manufacturer did not specify any rating which is what I am interested in before buying an amp

[GnP]

@SaiGadde Sorry, completely misunderstood your question and jumped the gun. I managed to dig up some more info, hope it helps.

[Sai Gadde]

From my ALC269 datasheet I found typical vales for vrefout (2.5v typical, 4.9V max) and Vrefout current(5mA typical, no max value given). It turns out power rating is about 12.5mA typical from these values.