Abstract: A vibratory roller is disclosed having an improved amplitude control device giving infinitely variable vibration amplitude which can be both increased and decreased. The roller includes a roll having a coaxial shaft driven at an angular velocity exceeding that of the roll. The rotary shaft has a transversely mounted cylinder within which an eccentric mass is slidably mounted for movement between physical constraints which limit the radially innermost position and the radially outermost position. The eccentric mass and cylinder define a piston cylinder arrangement having a control chamber which communicates with an actuating assembly that regulates radial position of the eccentric mass. The actuating assembly may include a pilot operated check valve and a valve assembly to govern communication between both a pressurized fluid source and a fluid reservoir with one side of an actuating motor piston.