Maxon 9-Series Dbx Compressor DBX compression circuit with threshold, ratio and gain controls and reduction status LEDUp to 30 dB of clean gain boost with a 10:1 compression ratio18-volt circuitry provides maximum head room with ultralow noise operation. Up to 30 dB of clean gain boost with a 10:1 compression ratio is available 18-volt circuitry provides maximum head room with ultralow noise operation