Abstract: A chromatic chorded zither is provided with at least one auxiliary damper comprising a rigid bar having string-engaging damping pads for converting the instrument for play in a diatonic scale. In one version of the instrument, retainers are provided on the chord bar housing for removably mounting the auxiliary damper alongside one of said chord bars, with the damping pads held in engagement with predetermined strings. In another version, the auxiliary damper bar has a tongue which fits into an opening of the chord bar housing. The damping pads of the auxiliary damper are arranged in a pattern to mute all strings of the instrument other than those corresponding to the diatonic scale for a particular key. With a set of several auxiliary dampers, the chromatic instrument can be converted to play in any one of several diatonic keys. The damper bars can be readily installed or removed with one hand, and take up very little room.