Noob Question about mobile pre-amp

hey guys, im very new at this. i did a little research and got a fairly good set up. i got an mxl 990 & 991 along with the m-audio mobilepre usb preamp. everything is working great except when i record, it only records to one channel instead of both (sound only in one speaker.

i can fix it using a filter in audition but im wondering if perhaps getting an xlr y cable to plug in to both channels would work fine without busting the mic that uses phantom power from the preamp or if there is another simpler solution.