At least 6 U.S. Presidents recorded conversations while in office. Hear those conversations on this C-SPAN podcast. 

Season 2 focuses on President Richard Nixon's secretly-recorded private telephone conversations. Through eight episodes, hear Richard Nixon talk with key aides about Watergate strategy, potential Supreme Court Nominees, and hear his reaction to the leaked publication of the Pentagon Papers. 

Season 2: President Nixon 

Season 1: President Johnson