Guys, we have a project wherein we need to use a 40kHz ultrasonic transducer to penetrate through a 4-inch thick of a fresh concrete mix. we are using a 40kHz ultrasonic transducer rated to work up to 50 watts. do you guys know any working schematics for such an amplifier? we saw some drivers in the net and can be bought around $50 but due to time constraints we cannot order abroad and wait. we are from the philippines.