The invention provides an ultrasonic transducer assembly for a bonding apparatus, comprising a bonding tool mounted to an amplifying horn secured between first and second ultrasonic-generating means. A method of forming a transducer for a bonding apparatus is also provided, comprising the steps of providing an amplifying horn, securing first and second ultrasonic-generating means to the amplifying horn such that the amplifying horn is located between said first and second ultrasonic-generating means and mounting a bonding tool to the amplifying horn.