this noise is commonly referred to as coil whine and is made by any high voltage electrical component. The sound comes from the electron gun which has very high

this noise is commonly referred to as coil whine and is made by any high voltage electrical component. The sound comes from the electron gun which has very high voltage passing through it. If you cant hear it you have hearing damage because most crts make the noise just on the edge of human hearing https://en.wikipedia.org/wiki/Electromagnetically_excited_acoustic_noise_and_vibration https://en.wikipedia.org/wiki/Electromagnetically_excited_ac...