A system and method for maintaining a substantially constant gap between a horn and an anvil includes the act of positioning a horn proximal an anvil, so that a gap is established between the horn and the anvil. An alternating current (AC) signal is applied to a converter coupled to the horn. The AC signal exhibits an amplitude. The amplitude of the AC signal is adjusted during operation of the horn, so as to maintain the gap between the horn and the anvil substantially constant.