SP-404 Keeps Making Buzzing Sounds

[DJ Magnum]

Hey guys, i'm new to the Roland family and have a couple of question in regards to sampling with the SP-404 and one of my Technics 1200mk2 turntables. For some reason, the sound levels of the records sound very low (especially in comparison to the SP's built in drum library). As a result I am forced to raise the volume on my monitor and on the SP.

Doing this creates the worlds most obnoxious buzzing sound! I cant begin to describe the nightmare I go through transferring the samples to Adobe Audition where I then have to amplify and reduce the hissing.

My setup is as follows:

I have my stereo monitor's rca cables connected to the SP's LINE OUTPUTS and my turntable connected to the LINE INs.

Also the ground wires on my turntable are connected properly so that cant be the problem.

I understand just reading this problem is a headache so any feedback will GREATLY be appreciated.