As a teenager in the 1970s, hip hop pioneer Grandmaster Flash hacked together his own DJ mixer in his bedroom. At the time, he was attending a vocational high school in the Bronx where he had developed some electronics repair chops. Flash needed his Sony microphone mixer to have a cueing feature enabling him to preview the mix before crossfading the turntable's audio to the speakers. So he hit Radio Shack for the parts and made a new musical tool, and history.
For more on the history of the DJ mixer, see this classic Cuepoint feature.
(via Kottke)
