The oldest reference to any "* ruin a hobby" I found is from the September 1985 Cincinnati Magazine:
Nothing will ruin a hobby more effectively than the feeling that your spouse resents it.
And "* ruin my hobby" in a 1985 article in Runner's World:
Roy Benson gave up his full- time job with the Atlanta Track Club, he says in Racing South magazine, because "I don't want my job to ruin my hobby. Running is my hobby, my first love. I just don't want to burn out on it. ...
And finally, very neatly, "* ruin your hobby" is also from 1985, in Creative Crafts and Miniatures:
In the long run, too many shows can ruin your hobby.
The first and last of these don't have the same meaning, but the second is spot on.