Fiio E9 problem with preoutput

Hi all, I have got a e9 today which headphone out in front works like a charm and it is docked with a e7. The only problem I have with it is the Preoutput does not output any audio even though i have already unplugged both the front jacks. When i insert a headphone jack into the Line in jack I can hear the current audio being played that has no effect on volume even though I flip the gain switch Any one can offer any help. Thanks alot.

foobar > usb > fiio e7/e9 > akg k702

I have a pair of jbl creature 3 speakers which i want to use connect to the fiio e7/e9 also, so I thought it should be connected to the preoutput since the jbl themselves have volume control. I don't have rca cables with me so i cant try the rca out. Thanks.

I see, my thanks to all of you. I will try to get in touch with my supplier to see if  he is willing to do a return. Thanks