Headphone amp. necessary to add headphone out?

I am considering to purchase a Alesis NanoPiano, but I need to use it with a headphone, and theAlesis NanoPiano don't has headphone out !

Do I need to add a headphone amplificater or will an adapter on the line out jack be OK ? are there some tiny headphone amplificater that are not too expensive, with good quality ?

thanks

As far as i can see on the web, the NanoPiano does not have a mono out, am I right? You could use a adaptor and plug it in the L or R out, but it would be a shame because you would probably only receive mono signal if not signal in only one side of the headphones.

My advice would be to invest in a proper adapter L+R-jacks -> female-minijack.

You could use something like this:

http://www.musiconmypc.co.uk/35mm-stereo-jack-to-2-x-63mm-mono-jack-10ft-p-323.html?osCsid=b9acce99497bf5e3d31123360059afaa

Combined with a female-female minijack adaptor:

http://www.getprice.com.au/3-5mm-Stereo-to-3-5mm-Stereo-Coupler-Joiner-Female-Gpnc_41--23451979.htm

A bit of a big setup for listening to stereo, but it'd be worth it, if headphones is all you have!

Doesnt what your going to plug it into have a headphone jack? Either mixer or instrument amp. If your useing powered monitor speakers instead, then some sort of stereo headphone amp plugged into right and left outs on the keyboard would be best choice. Regular instrument line outs are not headphone compatable. Though a few guitar processors with single stereo out have designed them to work well with both headphones and instrument amp inputs.