An apparatus for preventing audio and/or video alterations and distortions with origin external and internal to electrical power supply systems at low or very low voltage, in direct or alternating current, comprising: at least one Phase input and one Neutral input, in use, connected by derivation to a Phase and a Neutral of the electrical power supply system to receive an electrical voltage signal; an external casing internally presenting a containment compartment; an internal tuner-damper core arranged in the containment compartment of the external casing and comprising a mixture selected from a consolidated sediment or an incoherent sediment, which are non-hygroscopic, of particles of a piezoelectric, pyroelectric material, possible semiconductor and possible refractory inert, in air, configured to detect and transform electromagnetic energy at the origin of disturbance phenomena, into mechanical energy and thermal energy; said internal tuner-damper core comprising a first polar electrode and a second polar electrode both partially inserted inside said mixture (3a, 3b) and in contact therewith; said first and second polar electrodes, being connected to a respective Phase input and a Neutral input to receive said electrical voltage signal; said internal tuner-damper core comprising at least one ground bias and heat dissipation bar at least partially immersed inside said mixture (3a, 3b), but spaced apart from said polar electrodes, and connected, in use, to a grounding system; characterised in that said internal tuner-damper core is inserted in a dedicated casing (12, 15) of dielectric material and determines a first high-frequency, HF, chamber, said apparatus further comprising an external tuner-damper core bordering and integrated with the internal tuner-damper core; said external tuner-damper core being arranged externally to the internal tuner-damper core so that it is interposed between the external casing, which is preferably metallic, and the internal tuner-damper core so as to determine a second high-frequency, HF, chamber; said external tuner-damper core comprising a mixture of a sediment in incoherent form, which is non-hygroscopic, of particles of a piezoelectric, pyroelectric material and possible semiconductor and possible refractory inert, in air, configured to detect and transform the electromagnetic energy at the origin of the disturbance phenomena into mechanical and thermal energy. at least one Phase input and one Neutral input, in use, connected by derivation to a Phase and a Neutral of the electrical power supply system to receive an electrical voltage signal; an external casing internally presenting a containment compartment; an internal tuner-damper core arranged in the containment compartment of the external casing and comprising a mixture selected from a consolidated sediment or an incoherent sediment, which are non-hygroscopic, of particles of a piezoelectric, pyroelectric material, possible semiconductor and possible refractory inert, in air, configured to detect and transform electromagnetic energy at the origin of disturbance phenomena, into mechanical energy and thermal energy; said internal tuner-damper core comprising a first polar electrode and a second polar electrode both partially inserted inside said mixture (3a, 3b) and in contact therewith; said first and second polar electrodes, being connected to a respective Phase input and a Neutral input to receive said electrical voltage signal; said internal tuner-damper core comprising at least one ground bias and heat dissipation bar at least partially immersed inside said mixture (3a, 3b), but spaced apart from said polar electrodes, and connected, in use, to a grounding system; characterised in that said internal tuner-damper core is inserted in a dedicated casing (12, 15) of dielectric material and determines a first high-frequency, HF, chamber, said apparatus further comprising an external tuner-damper core bordering and integrated with the internal tuner-damper core; said external tuner-damper core being arranged externally to the internal tuner-damper core so that it is interposed between the external casing, which is preferably metallic, and the internal tuner-damper core so as to determine a second high-frequency, HF, chamber; said external tuner-damper core comprising a mixture of a sediment in incoherent form, which is non-hygroscopic, of particles of a piezoelectric, pyroelectric material and possible semiconductor and possible refractory inert, in air, configured to detect and transform the electromagnetic energy at the origin of the disturbance phenomena into mechanical and thermal energy.