TrollDragon
Headphoneus Supremus
Then there might just possibly be the same circuitry in the X3 as well. I know there is a switch on the headphone jack to pause or start playback if you plug or unplug the headphones.I was probably thinking of the X5:
http://www.head-fi.org/t/661411/fiio-x5-thread-info-updated-on-jan-17th-2014/11370#post_10746727