Built around Rupert Neve’s custom transformer designs, the 543 module provides individually controllable threshold, attack, release, makeup gain, ratio, sidechain HPF, Feed-forward/Feed-back selection and Peak/RMS detection modes. With the compressor inactive, the 543 may be used as a transformer-coupled, high-performance line amplifier. Two 543s may be linked for stereo operation.

One of the more unique features of the 543 is the new Peak/RMS mode also found in the Portico II Channel. This switch allows the VCA (voltage control amplifier) to respond to both RMS (Root Mean Square) and peak levels. RMS circuits are considered to better mimic the way the ears perceive apparent loudness, while peak circuits tend to directly respond to the waveform voltage, which may be more of a concern for prevention of clipping and maximising levels. In this case, peak mode uses a combination of both methods to get the best of both worlds, and avoids the drawbacks of each method on its own.

The 543 also has the ability to switch between feed-forward and feed-back modes. In most of Rupert Neve’s earliest designs, feedback detection – controlling the VCA with a rectified voltage from the unit’s output – was intrinsic to the musical dynamic response. However, the very nature of a feedback compressor limits the attack time of the compression circuit. To offer faster, more technically accurate response times, feed-forward detection was implemented on Neve’s more modern designs. With the unit’s FF/FB switch, both classic and modern VCA responses are available.

The chassis of the 543 module is built to standard 500 series specifications, with power and I/O provided by the rack.

More: www.rupertneve.com