The prospects of the practical application of reflex triodes are connected with the constructional features of these high-power microwave oscillators. The results of experimental investigations of an original design of a reflex triode are presented. A scheme of the triode allows provision of a symmetric current supply to the device grid. A linear induction accelerator (LIA) with low source impedance has been used. The LIA is made using a composition approach, where the main parts of the accelerator are placed within one cylindrical tank.