Abstract: Amplifier for radio frequencies including first and second common-base-connected transistors in push-pull coupling; an input transformer including two identical input windings each in series connection with the emitter of the respective first and second transistor and an input signal; an output transformer having a primary winding divided by a centertap into two identical half windings and having a start and an end terminal respectively connected to the collector of said first and second transistor and being connected to a supply potential at the centertap. The output transformer further includes a secondary winding connected to a load and identical first and second feedback windings in series connection with the respective emitter of said first and second transistor. Each feedback winding is such oriented that a fraction of the output signal is inserted in the input signal in opposite phase thereto for providing negative feedback.