For some reason, the sound is clipping with my Q.Bert needle. Why is this?

With some equipment with inadequate headroom, the output voltage of the Q.Bert is too much.  This is a rare circumstance, but is known to happen occasionally.  This is not a flaw on the part of Ortofon, but instead a problem with the equipment being used in conjunction with the cartridge.  If your turntable has a built-in phono preamp (offers a line-level output), try disengaging it and using your DJ mixer for preamplificaton.  Conversely, if your turntable has a built in phono-preamp, you can also try the opposite - engaging the built-in preamp and using the line input on your DJ mixer.