Vintage vs modern phase 100, anyone work with both

[Snow007]

I'm trying to get my hands on a MXR Phase 100 and I have a chance to get a model from the late 70s or early 80s that has no led or input jack that runs solely off batteries.

Does anyone have experience with both a vintage and modern MXR Phase 100? Is one much noiser than the other? Does one sound much better? Do either of them ever have true by-pass?