First thoughts would be a loose connection somewhere, try opening the plug and checking connections in there. Have you tried it in different socket? does it still hum? Where is it located? next to any large white goods?
Check all connections in the plug, try it in a different socket, another house?? check the mains lead and speaker cables for damage on the insulation. Disconnect the aerials, does it still hum?
its not the areal thers no damage to insulation and what ive realised is thers a hum and a hiss when i turn the volume to zero the hiss goes but the hum remains and i have no idea how to check the plug
Have a look at this post, also i think theres been a few threads in the past with people complaining of noisy headphone sockets on the DM37 so may be worth doing a forum search.