RupertNeve Designs 5043 Compressor/Limiter Duo at a Glance:

ü UseIndependently or Linked

ü Busor Line Input Selection

ü Howit Works

ü FeedForward or Feed Back?

ü Ratioand Threshold

UseIndependently or Linked

ThePortico 5043 embodies two independent Compressor-Limiters (Channels A and B)housed within a half rack, 1U module. They can be used independently orconnected in sequence to provide two separate control slopes. When usedindependently, linking the D.C. control circuits via a front panel push-buttonenables the level of each unit, "A" and "B", to be held ina constant relationship. Rear panel TRS connections are provided to linkmultiple 5043s. This linking may also be extended to the former AMEK CIB andDMCL units. When used in sequence, the Portico 5043 can be configured easily toprovide dual slope compression and limiting.

Busor Line Input Selection

Anynumber of Portico modules that are equipped with the "To Bus" buttonmay be sent to the Bus input of the 5043 which makes it the ideal choice toform the core of a simple and cost-effective Portico mixing system. The Lineinput, when selected, provides a dedicated, transformer-balanced 10K impedancebridging input so that the 5043 may be inserted or included in any appropriatepart of the signal chain at console line-up level.

Howit Works

Inorder to control gain, a V.C.A. or Voltage Controlled Amplifier (or Attenuator)is used. There are many types of V.C., including the use of tubes, discrete andintegrated solid state circuits, and naturally non-linear devices, with eachone having its characteristic behavior that reflects sonically on the finalperformance, and gives it a character or signature that can be musicallyattractive. The Portico 5043 makes use of a very accurate, low noise, lowdistortion V.C.A. having, essentially, no signature of its own.

A partof the audio signal is rectified and smoothed to produce a suitable controlvoltage for the V.C.A. which has to respond very quickly and have lowdistortion. If the response is too fast, low frequency signals will themselves,be gain controlled! If the response is too slow, the signal will overshoot andthe first few cycles will not get compressed. The speed and accuracy of theresponse, known as the "attack," and the time frame that gain remainsunder the initial control, known as "release" or "recovery"and plays a large part in the way a compressor sounds.

All Porticomodules use input and output transformers and almost entirely discretecomponent amplifiers. In fact, the Line amplifiers on their own, inserted intothe signal chain, are capable of enhancing the sonic quality of many signalsources, especially those of digital origin. These are some of the factors thatenable the Portico 5043 to work so unobtrusively within the context of a veryhigh quality audio chain.

FeedForward or Feed Back?

ThePortico 5043 provides a choice of feed-forward or feed-back compression modes.The FB Button allows the user to switch between the two modes. If the V.C.A.Control voltage is taken from the 5043 input, (i.e. before the V.C.A.) theV.C.A. knows right away that a gain change is required and there is almostimmediate response. This is known, logically, as a "Feed-Forward"compressor.

If theV.C.A. Control voltage is taken from the 5043 output, (i.e. after the V.C.A.)it cannot act immediately on the V.C.A. because it has already been modified bysettings of the V.C.A. and circuits through which it has passed. This is knownas a "Feed-Back" compressor. The two compression characteristics arequite different; there is more "Overshoot" and both the attack andrecovery ramps are changed, providing the user with powerful choices. Almostall of Neve's earlier designs were "Feed-Back". They were moremusical and sweeter than with "Feed-Forward" designs; however the"Feed-Forward" design provides greater accuracy.

RupertNeve Designs 5043 Compressor/Limiter Duo Features:

ü GainRange: Continuously variable from -6 dB to +20 dB.

ü ThresholdRange: Continuously variable from -36 dB to +22 dB.

ü RatioRange: Continuously variable from 1.1:1 to "Limit" (40:1).

ü AttackRange: Continuously variable from 20mS to 75mS

ü ReleaseRange: Continuously variable from 100mS to 2.5 Seconds.

ü FF/FB:Feed-Forward or Feed-Back VCA control.

ü S/Cor LINK: Multiple 5043's may be daisy-chained via the rear panel jacks.

ü External15V Supply included with every Portico Series module.