Most recent Salvi lever harps like the Juno, Mia, Hermes, Titan, Una and Gaia - use newer semi-tone levers from the "Start & Play Series".

These come in a few different sizes - but the same principle exists to ensure they don't buzz, by ensuring the lever screw and nut are tight.  Your harp should have come from the factory with a tool set and leaflet (2 allen keys and spanner).  Below is a video created by Salvi's in-house harp technician explaining and basic instructions.

Down load instruction sheet as PDF here.