phono preamp crackling

i recently added analog to my system and i'm having a problem. my phono preamp will often emit crackling noises. this occurs even when i take the stylus off the record--the crackling will continue.

i've tried locating the preamp in different locations--above the turntable (very bad), below the turntable (better but not good) and as far from my integrated amp as i can, which isn't too far, about 1.5 feet above the amp. the impedence and gain settings on the preamp are at the recommended level for my MM cartridge.

if location of the phono preamp is the problem then i'm in trouble, as i don't have many options for where to put it.

the phono preamp is connected to my integrated amp using balanced cables. the system is: marantz 15s1 tt, ps audio gcph phono preamp and cambridge audio 840v2 integrated.

any suggestions on what to do or what the problem might be?

thanks!