Manley Variable Mu®, the gold standard in tube compression

The Manley Variable Mu® Limiter Compressor has defined professional stereo buss compression since 1994. This all-tube, transformer-coupled design utilizes the remote cut-off technique—re-biasing vacuum tubes to achieve gain reduction—delivering smooth, musical compression that unifies mix elements without audible artifacts. With custom hand-wound Manley transformers featuring nickel laminations and a fully differential signal path, the Variable Mu® provides exceptional transparency across its 20 Hz to 25 kHz frequency response.

High Pass

The High Pass Side Chain (HP SC) filter is a crucial feature that prevents the compressor from "pumping" or over-reacting to bass frequencies. When engaged, the filter tells the compressor's detector circuit to ignore sounds below 100Hz. This means that a kick drum or a heavy bass line will not trigger the gain reduction, allowing you to compress the rest of the mix—like vocals or guitars—without the low end of the track causing unwanted "breathing" or rhythmic side effects.