<h1>Rupert Neve Designs 543 — 500-Series Mono Compressor/Limiter</h1>
<span style="font-size:16px; font-style:italic;">Unobtrusive dynamic control with selectable feed-forward/feedback modes, Peak/RMS detection and a built-in sidechain high-pass filter</span><br /><br />
The Rupert Neve Designs Portico 543 is a 500-series version of the highly regarded Portico 5043. The Portico 543 module is a full-featured compressor-limiter that allows you select between highly accurate feed-forward operation and the sweet musicality of feedback-style compression. Drawing on the unrivaled heritage of Mr. Rupert Neve along with an impressive feature set, the 500-series Portico 543 gives you the sonic signature of Neve’s custom transformer designs, individually controllable threshold, attack, release, makeup gain, ratio, Peak/RMS detection, and a built-in sidechain high-pass filter. On top of that, with the compressor inactive, the 543 compressor can be used as a transformer-coupled, high-performance line amplifier. Plus, two Portico 543 compressors can be linked for stereo operation as well. The Portico 543 chassis is built to standard 500-series specifications, with power and I/O provided by the rack.<br /><br />
<h3>Rupert Neve Designs Portico 543 Compressor/Limiter unique features:</h3>
<ul>
	<li>Selectable feedback and feed-forward operation for classic or modern VCA response</li>
	<li>Selectable Peak/RMS operation for clip prevention or natural-sounding program compression </li>
	<li>Selectable 250Hz sidechain high-pass filter prevents sustained bass from activating compression </li>
	<li>Can be used as a transformer-coupled, high-performance line amplifier</li>
</ul>
<h3>Rupert Neve Designs Portico 543 Compressor/Limiter key features:</h3>
<ul>
	<li>Gain range provided is from -6dB to +20dB</li>
	<li>Ratio from 1:1 to 40:1</li>
	<li>Threshold range from -30dBu to +20dBU</li>
	<li>Attack time from 20mS to 75mS</li>
	<li>Release/Recovery Time: Range of release time is 100mS to 2.5 Sec.</li>
	<li>Stereo link operation also allows ducking</li>
	<li>Two Peak LED meters show output level and gain reduction </li>
</ul>
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<h3>INSIDE THE BOX — Rupert Neve Designs Portico 543 Compressor/Limiter</h3>
<h3>How the Compressor Works</h3>
In order to control gain, the Portico 543 compressor-limiter makes use of a very accurate, low-noise, low-distortion VCA having essentially no signature of its own for sonically transparent gain reduction. 
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All Portico modules use input and output transformers and almost entirely discrete component amplifiers to produce the musical signature for which they are known. These are factors that enable the Portico 543 to work unobtrusively within the context of a very high-quality audio chain.<br /><br />
<h3>Feedback/Feed-forward</h3>
The 543 also has the ability to switch between feed-forward and feedback modes. If the VCA Control voltage is taken from the 543’s output, (i.e. after the VCA) it cannot act immediately on the VCA because it has already been modified by settings of the VCA and circuits through which it has passed. This is known as a feedback compressor. The two compression characteristics are quite different; there is more overshoot and both the attack and recovery ramps are changed, providing the user with powerful choices.  In most of Mr. Rupert Neve’s earliest designs, feedback detection controlling the VCA with a rectified voltage from the unit 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 Mr. Rupert Neve’s more modern designs. With the FF/FB switch, both classic and modern VCA responses are available.
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<h3>RMS or Peak?</h3>
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 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 maximizing 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.
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<h3>Ratio and Threshold</h3>
Above a given threshold, signals are reduced by an adjustable amount ranging from 1:1 (which is linear, or no reduction at all), to more than 40:1 which is equivalent to that of a limiter. Ratio is sometimes referred to as slope, because when depicted on a graph, the slope of the graph representing output versus input is what changes. Threshold control covers the Range from below -30dB to +22dBu. When threshold is set at a low level with a fairly high ratio, the amount of gain reduction will be considerable and it may be necessary to use some gain after the compressor to restore the apparent signal level.
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<h3>OUTSIDE THE BOX — Rupert Neve Designs Portico 543 Compressor/Limiter</h3>
<strong>Compression:</strong> 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<br /><br />
<strong>Gain:</strong> Gain range provided is from -6dB to +20dB. As already noted, when compression has taken place, it may be necessary to increase the overall gain to restore the apparent program level<br /><br />
<strong>Peak:</strong> When engaged, the 543 uses a combination of peak and RMS (average) detection to determine level. When disengaged, it follows just RMS<br /><br />
<strong>SC HPF:</strong> Introduces a HPF at 250Hz to the VCA side chain signal. This allows the compressor to disregard sustained low frequency content<br /><br />
<strong>Ratio:</strong> Range from 1:1 to LIMIT (i.e. 40:1)<br /><br />
<strong>Threshold:</strong> Range from -30dBu to +20dBU<br /><br />
<strong>Attack Time:</strong> Range from 20mS to 75mS<br /><br />
<strong>Release / Recovery Time:</strong> Range of release time is 100 mS to 2.5 Seconds.<br /><br />
<strong>Stereo Operation:</strong> 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<br /><br />
<strong>Ducking:</strong> When the link switch is engaged on two connected Portico 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<br /><br />
<strong>Meters:</strong> Two Peak LED meters are provided that show output level and gain reduction. The output level meter covers the range from -10 to +22dBu and above which is regarded as overload. Reduction is calibrated in dB covering the range +1 to 22dBu, reading from right to left
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<h3>Who’s using Rupert Neve Designs </h3>
Seriously?
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<h3>About Rupert Neve Designs</h3>
In 2005, the company acquired new premises in Wimberley, Texas to handle the increasing demand for products embodying the principles of very high musical quality that has become synonymous with Rupert Neve’s name over the years. Rupert Neve Designs announced the Portico Series in 2005 to much acclaim. The Portico Series modules are high quality analog building blocks for the front and back ends of digital systems (hence the name “Portico” as in entryway). In the years since release, the Portico Series has already garnered many important industry awards including five TEC awards, multiple PAR Excellence Awards, Mix Certified Hit Awards, and a MIPA award among others.
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The original color scheme featured grey powder coating with a black and red inlay design available in both horizontal and vertical configurations. The first eight units were the 5012 Dual Pre, The 5042 True Tape FX, The 5032 Mic Pre EQ, The 5043 Dual Mono / Stereo Compressor, 5033 Five Band EQ, 5016 Mic Pre/DI (discontinued), 5014 Stereo Field Editor, and 5015 Mic Pre Compressor. <br /><br />
In 2009, the 5088 High Voltage and Discrete Mix System were released as the ultimate word in mix bus sound quality. The modular mix system is configurable to the user’s needs, and utilizes the various Portico Series modules for mic preamps and signal processing. The 90-Volt rails of the 5088 provide more than 10dB more dynamic range than any other Rupert Neve designed console, and the custom transformers on every input and output provide complete galvanic isolation. With the release of the 5088 Portico Series modules also received an update with the same style of light blue powder coating with anodized aluminum knobs.<br /><br />
<h3>The Portico 543 Compressor-Limiter will add both classic and modern gain reduction to your 500-series collection the way only a Rupert Neve-designed compressor can. For more information, call or chat with an RSPE representative today.</h3>
<br />This product is also available as part of the RSPE Demo 4 Free & Rental Program, <span class="colors_productprice" style="font-weight: bold; text-decoration: underline;"><a href="http://www.rspeaudio.com/Rupert_Neve_Portico_543_RENT_p/rnd-543-cmp-rent.htm" target="_blank" class="colors_productprice">click here</a></span> to see the rental product page.