The 543 Mono Compressor delivers the unobtrusive, musical-sounding dynamic control and brick-wall limiting made famous in the Portico 5043 to the 500 series format. The 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 yields a combination of rich warmth, flexibility and precision that is sure to resonate in the ears of sound engineers the world over. Built around Mr. Rupert Neve’s custom transformer designs, each 543 module encompasses individually controllable threshold, attack, release, makeup gain, ratio, side chain 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, and two 543 may be linked for stereo operation as well. The chassis is built to standard 500 series specifications, with power and I/O provided by the rack.
Rupert Neve Designs 543 Features:
Compression For signals below the “threshold” level that has been set, a compressor provides a linear path allowing signals to be amplified without the gain being adjusted in any way. When signals exceed the “threshold” level, the gain is reduced in a controlled manner that depends on the Ratio that has been set.
Gain GAIN range provided is from -6dB to +20 dB. As already noted, when compression has taken place, it may be necessary to increase the overall gain to restore the apparent program level
Peak When engaged, the 543 uses a combination of peak and RMS (average) detection to determine level. When disengaged, it follows just RMS.
SC HPF Introduces a HPF at 250Hz to the VCA side chain signal. This allows the compressor to disregard sustained low frequency content.
Ratio Range from 1:1 to LIMIT (i.e. 40:1)
Threshold Range from -30dBu to +20dBU
Attack Time Range from 20 mS to 75 mS.
Release / Recovery Time Range of RELEASE time is 100 mS to 2.5 Seconds.
Stereo Operation When the LINK switch is engaged on two 543 modules and settings are approximately the same values, GAIN reduction on both channels will be the same to preserve stereo balance and position. This will work properly in link buss enabled 500 series racks, or by hardwiring two 543 modules link busses together in non-compatible racks.
Ducking When the LINK switch is engaged on two connected 543 modules, the signal passing through the first module may be used to control the amplitude of a second module. For example, the level of music through channel A can be controlled by speech on channel B, i.e. reducing the music level to make a “speech-over” announcement.
Meters Two Peak LED METERS are provided that show OUTPUT LEVEL and GAIN REDUCTION. Output level meter covers the range from -10 to +22 dBu and above which is regarded as overload. REDUCTION is calibrated in dB covering the range +1 to 22 dBu, reading from right to left.
Rupert Neve Designs 543 Specifications:
Gain Range: Continuously variable from 6 dB to +20 dB.
Threshold Range: Continuously variable from 36 dB to +22 dB.
Ratio Range: Continuously variable from 1.1:1 to Limit (40:1).
Attack Range: Continuously variable from 20mS to 75mS
Release Range: Continuously variable from 100mS to 2.5 Seconds.
FF/FB: Feed-Forward or Feed-Back VCA control.
Maximum Output Level: Balanced and Floating Transformer Output Maximum output from 20 Hz to 40 kHz is +23 dBu.
Total Harmonic Distortion and Noise: @ 1kHz, +20 dBu output level, no load. Main Output, compressor bypassed Better than 0.0006%. Main Output, compressor engaged Better than 0.02% Noise: Measured at Main Output, un-weighted, 22Hz-22kHz, Terminated 40 Ohms. With Gain at Unity, Compressor disengaged Better than 103 dBu. With Gain at Unity, Compressor engaged: Better than 92 dBu
Frequency Response: Main Output, Unity Gain @ 18 Hz, +/- .1dB @ 150 kHz -3 dB.
Crosstalk Measured Channel to Channel: Better than 90 dB @ 15kHz.