Abstract: This invention is an improved electronic detection system for leaks in articles such as can tops and the like comprising a special ultrasonic microphone-amplification system for listening for leaks in articles, a signal averaging network to receive the signal produced by the amplifier and to improve the signal to noise ratio, an enable circuit which is synchronized with the pressurization of the article to be leak tested and which triggers the signal averaging network and a comparator to receive the averaged signal from the signal averager. The comparator produces a logic pulse for rejecting leaky articles when the averaged signal produced by the signal averaging network is above a predetermined level.