Abstract: There is described a servo-control system incorporating a double-acting ram which is responsible for compensating electro-hydraulically for the imbalance in a servo-controlled load in order to achieve a high performance. To this end, a compensating loop is produced which slaves a balancing pressure P.sub.e to the variations in the imbalance. This pressure is exerted in one of the chambers of the ram, separately from the control pressure. It is governed by a pneumatic accumulator whose load is a function of the lack of balance between the pressure exerted by the imbalance and the balancing pressure.