Retro Instruments STA-LEVEL Replica of 1956 Gates Sta-Level CompressorThe Retro Sta Level is a replica of the legendary 1956 Gates Sta Level. The Sta Level dominated the sound of hit radio in the 1960's. Now these super musical sounding compressors have found their way into today's hits. The Retro Gold Edition celebrates fifty years of the products existence. The Sta Level uses the coveted 6386 tube in a classic G. E. circuit design. Alternatively, the Gold Edition Sta Level uses a pair of commonly available 6BJ6 tubes