Right, they aren't the same animal. Hot is pretty close to what Jamn was in 1995-99 timeframe. They played some current hits, mixed in with a good amount of recurrents and gold, and some old tracks from the likes of Madonna, Bob Marley, Prince and Michael Jackson. The new hip hop they played was safe. If I remember correctly, Jamn played more currents back then than Hot does now though.
Jamn dropped a lot of those old tracks around 98/99 I think, and then went more Urban in 99/2000 when Hot 97.7 went on the air. I think they shifted back to a more pop sound around 3 or 4 years ago.