Well shielded tonearm cables?

Before you buy new phono cables, I recommend you experiment with ground connections.  I would first connect a wire to your preamp grounding post (or if it doesn't have one connect it to a chassis mounting screw), then connect the other end to exposed metal parts of the turntable and tonearm.  There are no guarantees but you may find this solves your problem.  It did for me a number of years ago when I had a VPI 19 Mk 3 with ET linear tracking tonearm.  I had occasional buzzing noises and occasional radio station interference, but the noises all disappeared when I connected a ground wire to the metal under-chassis of the VPI table.  In my case, the intermittent buzzing was due to dimmer switches on several lights in the house.  When the lights were on and the dimmer was used to lower the light level, the buzzing began.  However, this too disappeared when I attached the ground wire.

Try Stereolab Phono Master Reference RCA by legendary Chris Sommovigo, his cables are amazing. 

You could try KLE Innovations gZero3, 6, 10, 0r 20. These are the quietest cables I've tried so far

All of these cables perform to the same level from a noise perspective - they just improve on details, bass control and imaging as you go up through the range.

Checkout their web site for user reviews
http://kleinnovations.com/

They rely on their architecture to provide the "shield" to eliminate noise - and not a conventional shielding conductor .

But I also agree with Salectric - it could be a grounding issue with the TT - so I would start there, since all it takes is a piece of thin wire to try it.

You might also check to see if the arm tube is also correctly grounded

Regards...