Just Two Turntables and an Air Valve

this is the original mixer – two grammophones linked via a muthafrikkin AIR HOSE that acted as a crossfader.

they used it to play tunes along to silent films, then DJ Olde Schoole started getting busy…

http://gizmodo.com/5918634/first+ever-mixer-and-crossfader-dates-back-over-a-century