Chip douglas joined the turtles and played bass for a few years in mid 60s . Did happy together. Then in 1967 mike nesmith persuaded him to leave the turtles and produce the monkees. He produced pleasant valley sunday.
Chip Douglas only produced their later stuff which didn’t do too well, IIRC. Don Kirshner was one of the original producers and creators of the Monkees and the TV show.