A high power ultrasound application device (1) is provided which comprises a hand-held applicator (3). The applicator comprises a converter element (5) for converting electric signals into ultrasound waves a treatment head (6) configured to apply ultrasound waves from the converter element to a subject to be treated a handle (8) for holding and manipulating the applicator and an oscillator circuit (9) arranged in the applicator and comprising one or more electronic components (10A, 10B) configured to be energized by a power source and to generate an output signal to drive the converter element. The oscillator circuit is in thermal contact with the handle, and the handle comprises a heat conductivity and thermal coefficient such that, when manually held by an operator in normal use, a heat conductive channel is provided between at least a portion of the circuit and the operator.
