An annular Helmholtz damper for a gas turbine can combustor, the annular Helmholtz damper having an axis; an inner wall and an outer wall concentrically arranged with respect to the axis to define an annular damping volume arranged around a can combustor; a front and rear circumferential plates for closing the annular damping volume upstream and downstream; at least one intermediate circumferential plate arranged between the front and the rear plates for dividing the annular damping volume in a main and a secondary volume; and a plurality of intermediate drain holes passing the intermediate circumferential plate and configured for draining collected liquid from the main volume to the secondary volume.