Abstract: "Hands free" telephone sets in which there is connected in parallel with the terminals (A) and (B) of a first path (C.sub.1) comprising the coupling circuit of the telephone set in series with a controllable amplifier (11) of the receiving path (6), a second path (C.sub.2) comprising a controllable amplifier (12) which is controlled by a linear regulator (13) which keeps its output signal constant. The gains of the two amplifiers (11) and (12) respond to each other. A device is provided so as to ensure that the gain in the second path remains higher than the gain in the first path. A third controllable amplifier (5) is provided between the microphone (4) and the input terminal (A) which is used in common by the first and second paths; the said means (14) are adjusted in such a way that the electro-acoustic loop which is closed by the second path (C.sub.2) is permanently the source of non-annoying oscillations.