Radio Frequency Interference


I’m sure this has probably been covered before here, but, I’m relatively new so I will go ahead and ask anyway.

I recently switched out my tube preamp to an Audible Illusions Modulus. I have read good reviews and it posseses somewhat of a cult following. The rest of my components are a Cary 200.2 solid state Power Amp, Kef r700 speakers, a Cambridge Audio Azur that I use as my DAC with a Sonos Connect. I was using a Rogue Audio Cronus Magnum as my preamp with the power tubes removed. (I realize this is less than ideal since I was only using half of the circuit but, this was always meant to be temporary). I got zero radio interference through the Rogue, however, once I hooked up the Audible Illusions Modulus I immediately started picking up radio frequency. I have tried moving it around a bit to see if this eliminated the RFI but have not had any luck with this solution. Hoping there is an easy fix because I really love the sound quality I am getting when music is coming through the speakers and not radio frequencies...
Did you try to earth-ground the case?  I have lived in Oak Park Illinois for a while.  We had all sorts of unwanted interference.  Our TV - on standby would start "screaming" in the morning while answering machine was doing the same.  I noticed that it was happening when particular gray car was passing by.  This car had multiple antennas and it was cops - 100% sure.  How can you prevent it?  Ground what you can or just move.

Thank you!! Grounding worked! 

Much appreciated.