User Manual
6
The Rupert Neve Designs Portico II™ Channel
The Rupert Neve Designs Portico II Channel is a full 19” rack width, 3.5” (2U) with standard rack
mounting “ears”. As with the entire Portico II range, the construction incorporates a heavy and robust
steel shell that provides total magnetic screening and exceptional mechanical stability. The front panel is
machined from a solid .20 inch aluminum plate with a steel sub panel behind it.
The name says a lot about the device but certainly not everything. The audio electronics use higher
power supply voltage compared to most audio gear and in this case use +36 and -36 volt power supply
rails. The signal path has manysimilar circuits as the Rupert Neve Designs agship console, the 5088.
Amplication is handled with discrete (individual transistors) operational ampliers (gain blocks). These
discrete circuits are in the tradition of Rupert’s original circuits used in recording consoles from the 70’s
and in many ways sound similar, however there are renements in noise, slew rate, dynamic range and
particularly avoidance of unpleasant high frequency distortion artifacts. Also following Rupert’s tradition-
al approaches, these gain stages are married to custom designed input and output transformers. Not only
is the output transformer custom designed for the Portico II, it is the largest toroid output transformer that
he has used for a line level device.
Some wonder whether it is better to use a separate boutique mic pre-amp, EQ’ and compressor versus
a typical channel strip processor. In most cases, the separates have the advantage of “it is your choice”,
however one would hope to have a variety of choices to choose from and have made the best choices.
Another likely advantage for the separates is that most channel strips have at least one weak link, one
stage or processor that is virtually useless. However, most channel modules are relatively convenient and
easier to use and to patch.
The Portico II is a unique channel module in that each of the 3 main sections, the mic pre, the EQ and
the compressor are based on 3 separate products that each have the Rupert Neve heritage, a huge fan
base and stacks of great reviews. We also however have added renements and features to those circuits
like the SILK+ and TEXTURE knob, the De-Esser, the Blend and the FAST mode features that our friends
and customers suggested be added to the originals. Unnecessary circuitry (a few input and output stages)
could be removed while truly useful and convenient internal patching features could be added with a
few switches rather than with patch-bays and patch cables. While combining three modules into the
Portico II, we were able to add a few more features in the internal routing like the HPF to Side-Chain,
and the EQ / Compressor order selection. In this case, the sum is obviously greater than the individual
parts - you get 3 very powerful and versatile boutique processors that have evolved into this synergistic
channel module.
MICROPHONE INPUT
The microphone input is balanced but not oating, being a variant of an instrumentation amplier.
Our well-proven “Transformer-Like-Amplier” (T.L.A.) conguration is used, which includes an
accurate toroidal Common Mode Low Pass Filter that rejects Common Mode signals and excludes
frequencies above 150 kHz. (There are high powered broadcast transmitters at and above this
frequency in several Continents and, even if you can’t hear them, any vestigial intermodulation
products must be excluded!)
When the Mic Gain switch and Trim controls are set to Unity (0 dB) the Portico II microphone pre-am-
plier can handle a balanced input signal of more than +20 dBu without an input attenuator pad! This is
a unique feature that enables this input to double as an additional line input.