How can I connect headphone line from delta 1010LT sound card?

You'll have to get an adapter that goes from RCA to A quarter inch Stereo (if your headphones are 1/4 inch, if your headphone is 1/8 inch you'll have to get that size) The point is they make a number of adapters for going from RCA (this is what your Card puts out) To A different size; they make adapters (stereo) So go to Fry's and have the salesman help you out, or Radio Shack or Guitar Center or Best Buy and Maybe Target (some of the Big Box stores are carrying electronic stuff now a days. The Cheapest is Fry's..........~~~~~~~~*BB

On output of sound cardsare coloured sockets,headphone/speaker socket is green