A vertical cylinder fitted into a 90 degree fitting that connects to a pipe organ air supply. Said pipe organ air supply is admitted into said 90 degree fitting thence to said cylinder ultimately urging a plunger to rise off of stop. Said plunger rises until it passes vents that allow said pipe organ air supply to exhaust to the atmosphere. Said plunger then descends. Said plunger continues to rise and fall in this fashion inducing rhythmic pulses of said pipe organ air supply until said pipe organ air supply is withdrawn. Said rhythmic pulses induce a change in pitch and amplitude of the pipe organ pipes when sounded thus providing a tremolo effect. Use of said plunger in this manner eliminates prior art usage of mechanical valves, fans and motors to induce a tremolo effect, and reduces the need for complex and expensive maintenance.