'2A Style Optical Compressor No plug-in or other compressor type quite compares to the warm, forgiving, fluid qualities of the classic '2A optical compressor. For decades, the renowned '2A style circuit has become the go-to device for seamlessly handling vocals, bass, and a wide variety of other instruments and program material in an effortlessly smooth way. Releasing the WA-2A would be for nothing if it wasn't affordable. Since the start of Warm Audio, Warm has striven to give an unprecedented value to their customers, but putting high end audio within the reach of more people than ever before. This philosophy drives everything they do, and every product they offer. Premium Components: The WA-2A 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. A Four Tube Operation The WA-2A operates on four tubes: two 12AX7s, one 12BH7, and one 6aq5 (or 6P1J). We proudly use Tung-Sol and Electro-Harmonix brand tubes in the signal path, which sound very open and LARGE. All four tubes are socketed for easy swapping and replacement.