The Warm Audio WA-1B is a tube optical compressor based on the Tube-Tech CL 1B. It's a 2U rack-size unit featuring a hand-wired discrete circuit, Lundahl transformers, and JJ/Tung-Sol vacuum tubes, designed to reproduce the smooth, warm Scandinavian sound. It offers low noise operation and supports ratios from 2:1 to 10:1, as well as fixed/manual time settings. Key specifications: Type: Tube optical compressor Circuit: 100% discrete, through-hole circuit Transformers: Custom large-core transformers from Lundahl, Sweden Vacuum Tubes: Selected JJ and Tung-Sol vacuum tubes Ratio: 2:1 to 10:1 (continuously variable) Time Settings: Fixed, manual, and combined (fixed/manual) attack/release Inputs/Outputs: XLR, 1/4-inch TRS (balanced) Features: Dual sidechain bus, true bypass Chassis: 2U rack size Other: VU meter (input/compression/output switching) Ideal for tracks like vocals and bass where you want to add analog warmth. This unit was purchased from Vintage King about 3 years ago and is 115V/230V compatible. It comes with the original box, manual, and power cable. There are some screw marks on the rack mount ears.