ChronoRank #35

The answer

1. #1Bartolomeo Cristofori builds the first piano1700Wikipedia
2. #2Adolphe Sax patents the saxophone1846Wikipedia
3. #3Leon Theremin invents the theremin1920Wikipedia
4. #4The Rickenbacker "Frying Pan" — first electric guitar1931Wikipedia
5. #5Robert Moog debuts the Moog synthesizer1964Wikipedia
6. #6Roland launches the TR-808 drum machine1980Wikipedia

Adolphe Sax patented the saxophone in 1846, but Leon Theremin's 1920 instrument went one better — it's the only one here you play without ever touching it.