The Warm audio wa-2a single-channel tube optical compressor is a high-voltage, Class-A opto-compressor, utilizing large-core CineMag USA Transformers, four premium vacuum tubes, and the legendary Kenetek opto-cell - considered by many to be the world’s finest. The Warm Audio WA-2A is a single-channel tube optical compressor that recreates a classic leveling amplifier originally released in the late 1950s. With Tung-Sol and Electro-Harmonix tubes, dual CineMag transformers, and a Kenetek opto-cell, the WA-2A offers smooth, warm compression ideal for vocals, bass, guitars, drums, and parallel submixes. Its discrete signal path is terminated with balanced XLR and 1/4" TRS input and output connectors, and delivers a high output with minimal noise.Use compress mode for moderate peak attenuation, or switch to limit mode for more aggressive gain reduction. Operation is simple and efficient, thanks to the adjustable gain and peak reduction controls. The "Pre-Emphasis" serves as a tone control for the sidechain; use this control to make the compressor's detector circuit less sensitive to either high or low frequencies, or keep it flat at the noon position. A large VU meter allows easy viewing of gain reduction or output level, and can be calibrated via a dedicated potentiometer.