Trying to use a preamp for a MC cartridge

I recently went out on a proverbial limb and purchased a EAT MC cartridge.  I knew that it would need a phono preamp and have now tried two brands, both with the same result, load distortion of the lp.  I have a Marantz SR 5014 that has a phono input.  It works well with a MM cartridge.  I am going from the turntable, to the preamp and then into the phono input on the receiver.  Am I doing something wrong?