The Manley Variable Mu Stereo Compressor Limiter is an all-tube, all-transformer staple to your setup with a high pass side chain mod included. It has become a mastering studio standard and has contributed to most hit records over the last decade. It works by using the remote cut-off or re-biasing of a vacuum tube to achieve compression. The unique 5670 dual triode is at the center of the peak-reducing and compression action constantly being re-biased by the vacuum tube rectified side-chain control voltages which cause this tube to smoothly change its gain. The compress mode is soft-knee 1.5 to 1 ratio while the sharper knee limit mode starts at 4 to 1 and moves to a more dramatic ratio of 20 to 1 when limiting over 12dB. The knee softens as more limiting is used. Distortion can be creatively used by turning up the input and turning down the output while using very little or no compression.