Maybe they make a DJ version with a phono pre. They don't have a regular head shell that you would mount a regular cart on. Its some type of quick connect setup.The quick-connect cartridge you're talking about is an Ortofon Concorde or one of the copycats. They're pretty standard fare especially for clubs, as they automatically have the correct overhang and overall geometry for any Technics SL12x0 series. Those are everywhere, available from Amazon, Guitar Center, Musicians Friend, etc.
Built-in phono preamps in SL1200s? Not so much.

