Using electronic diagram shown below can be made a very simple noise attenuator. The noise attenuator useful in FM reception, if the distortion occurs in some stereo broadcasts that disappear when switching from stereo in mono mode.
This effect is because, in most stereo reception of sound from left channel are in opposition with the right channel.
After connecting of the two channels in parallel (stereo to mono connection), the noise of the two channels cancel each other.
Montage use fewer electronic components and is based on transistors.
The entire assembly is powered by a DC voltage between 15 and 30 volts.