Electrostatic Drive Type
Electrostatic drive type identifies how equipment supplies the high-voltage audio signal needed by electrostatic headphones.
Electrostatic headphones require a specialised drive arrangement and a compatible bias supply. Here the distinction is between an active electrostatic amplifier and a transformer energizer. They connect to different upstream equipment, even when both are informally called energizers.
Electrostatic Drive Type — Headphone Amp
An active electrostatic amplifier takes a line-level audio signal and amplifies it to drive the headphones. A transformer energizer instead uses a separate speaker amplifier's output, steps up that signal and supplies the required bias. This determines which equipment must sit between the music source and the headphones.
Compare the documented input arrangement rather than relying on the product name. Check headphone socket type and bias compatibility separately: drive type alone does not establish either. A transformer energizer is not simply an adapter for an ordinary headphone socket, and an active amplifier does not require a speaker amplifier upstream.