Back in the early 80s when he was super paranoid about being copied he used to say he didn't use any effects. It's the kind of thing you remember because as a kid you are so surprised the first time you see a lie printed in a magazine.
If you pick one of those early years and google Eddie Van Halen effects you will quickly find a quote say
https://jasobrecht.substack.com/p/ed...interview-part
On “Where Have All the Good Times Gone,” do you have an Echo-Plex in the beginning?
Actually, that’s about the only effect that I ever really use. I probably did.