Electrostatic headphones are high voltage systems.
Electrostatic headphones are basically the same as electrostatic loudspeakers speakers - same operating principles, same basic circuits. To understand ES headphones, start by studying the readily available material on ES speakers. Modern electrostatic headphones often use high voltage amplifiers instead of step-up transformers. The high voltage source connects between the diaphragms in the earpieces and the center taps of the transformer secondary windings. The two end leads from each secondary go to perforated, conductive plates on either side of the diaphragm in each earpiece.