The invention of headphones was made in order to amplify sound. Headphones were invented by Nathaniel Baldwin in his kitchen, the exact year of his invention unknown. In 1910 when the US Navy needed to amplify sound, Nathaniel sold the headphones to them. The initial headphones by Brandes had no damping; hence were sensitive and produced rough sound. They used iron drivers which had a single ended or balanced armature and had no padding making them uncomfortable. Sensitive headphones, as in wireless radio, used the impedance of 1000 to 2000 ohms while those used in telephone around 75 ohms. The initial headphones were part of the vacuum tube’s circuit where they were connected to the positive high voltage battery terminal and the other side was connected to the ground. This proved dangerous as the voltage side was open to touch and could cause shocks to the person who touched it accidentally.
Headphones
