Rupert Neve 543 500 Series Mono Compressor/LimiterThe 543 features a fully controllable compressor limiter with feed forward feedback modes, Peak RMS detection and a built in side chain high pass filter. With an unrivaled heritage and a tremendous feature set, the 543 provides an astonishing degree of flexibility and precision. In contrast to a diode bridge design like the Rupert Neve 535 compressor, which adds a thick, very colorful tonality to the source, the 543 makes use of a very accurate, low