The zero ohm coil (NOS) is a special form of transformer core coil. Of course it is also made of the top material FERON, which is described in the chapter transformer core coils. With the NOS, an air gap is measured and precisely adjusted by hand between the two sheet metal packages used (I and E package). It determines the inductance of the coil and requires the utmost care during assembly. It must not become too small, otherwise saturation effects occur under high loads. The high manufacturing effort of the NOS is always justified when the highest impulse fidelity is required. of the playback is received. With our NOS internal resistances are possible, which cannot be realized with other coils. Vacuum impregnation is highly recommended for zero-ohm coils, as it audibly enhances their high quality and effectively rounds off the manufacturing process.