Plugging a turntable into the XDJ-RX

Hi,

I've owned my RX for quite some time now and have decided to explore vinyl mixing with the intent of using the mixer on the RX. I have bought a numark TT-1700 turntable and have plugged it into the left platter on the decks. The sound from the turntables is incredibly low, even when trim and master volume is turned right up it is at a below-average volume. 

I have plugged the turntables into different speakers and am experiencing the same issue. I understand that turntables sometimes need amps but I was under the impression the mixer would do this. Any help would be hugely appreciated.

Thanks,

Hywel.