White 2A Leveling Amplifier: Tube Optical Compressor by IK Multimedia

IK Multimedia says the compression happens inside an optically coupled element, a fluorescent panel that lights photo-resistors, with no electronic circuitry in the compression path itself. The developer also points to the tube output stage as the source of a harmonic enriching effect.

Driven harder, the plugin adds noticeable color. The developer describes the result as gentle, warm and fat compression, which suits material that needs smooth, consistent level.

The interface is kept simple. The peak reduction knob sets how much limiting is applied, and the gain knob sets the output level. Because the controls are this direct, the plugin is easy to use on a single track or across a whole mix.

IK Multimedia notes that it can be inserted across the stereo bus of a DAW, so one instance can level a full mix. The developer also highlights vocals and bass as typical sources, with vocals getting consistent level and less need for fader rides, and bass getting wide dynamics kept under control with subtle saturation.