I have a Woodford wall faucet on the house that has a bose bib separate from the valve. (Similar to included link - assuming the link works). It is about 25 years old.

This year it has begun to "vibrate/hum" a lot when the water is turned on until the valve reaches full open. Anything less than absolute full open, it vibrates/hums. The vibration is enough that the valve handle will actually turn from the vibration. Obviously, this goes through the whole house when the water is running. I realize most of the time valves should be opened fully, but this behavior is new, and sometimes it vibrates even full open. It doesn't seem like air in the line.

I had a plumber pull the valve assembly, but he could find nothing amiss - seals looked good, etc.

Any suggestions ?