I have a lenovo g700 model, and recently installed ubuntu 12, but there is no sound in the headphones, though the laptop speakers are working fine. Sometime I got sound in headphones and laptop speakers together, but I'm unable to figure, how can I get the sound only in the headphones. In sound settings,under the Output tab, there is an option for analog output only. I have windows also in the same system, in which everything is working fine. Thanks!