Rupert Neve Portico II Channel Strip
By Barry Rudolph
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The audio artistry of Rupert Neve is fully realized in the Portico II channel strip, which features his unique thinking on circuit design in its mic/line/DI input, EQ, VCA-based compressor and output sections. The single-channel, two-rackspace Portico has a sturdy steel case with a thick aluminum front panel and anodized control knobs. All push-buttons have LED lighting there are multicolor 16-LED gain reduction and output meters.
Inside construction is excellent with a large toroidal output transformer and field replaceable circuit board subassemblies using surface mount technology and ribbon cable interconnections. A Motien DC-to-DC converter supplies phantom power. In what seems to be a tribute to vintage Neve-designed console channel strips like the 1073, the Portico II's switches and pots are mounted on a steel subframe that mechanically isolates them from the front panel.
Microphone, line or direct source inputs are individually optimized for both their source impedances and typical operating levels. The mic input uses Neve's "Transformer-Like-Amplifier" topology and has a 10k-ohm, non-reactive input resistance that is said to load low-output mics in a nondetrimental manner.
There are front panel 1/4-inch DI and Thru input jacks for the 3-megohm discrete FET input circuit and, when a plug is inserted into the DI jack, a LED indicator lights up and the XLR mic input is automatically overridden.
Input gain is controlled from 0 to 66 dB in 6dB steps by a 12-position rotary switch, and fine adjustments are made by a +/-6dB pot. Push-buttons are provided for phase (polarity), mute and phantom on/off, and a signal-present LED glows green for -20dB levels (and higher) and red at +22 dBu.
After the polarity invert section but before the fine input gain pot is an interstage transformer custom-made by Rupert Neve Designs. Next is a 20 to 250Hz, 12dB/octave active Bessel high pass filter circuit that is switchable from the main signal path over to the compressor sidechain. The back panel has jacks for the sidechain send/returns and stereo linking.
The 4-band equalizer (-/+15dB boost/cut each) has a pair of fully parametric midrange (LMF and HMF) sections and LF/HF shelving/peak filters. The LF and HF filters have four frequency choices each. Designer Neve steals from himself with the reuse of his "Accelerated Slope" design for the HF/LF filters as found in his 1064 and 1073 modules.
The LMF and HMF bands have continuously variable Q from 0.7 to 5, and a 70 to 1.4 kHz range for the LMF, and 700 to 14kHz for HMF. There are in/out buttons for each of the HF and LF sections, and a single switch for both the LMF and HMF.
In what could be a design first, the de-esser circuit is built into the HMF section, where only that section's audio is reduced (in response to an "s") instead of the entire audio band via the unit's compressor section. And rather than simply hijacking the EQ's HMF section for de-essing, it's possible to boost/cut and de-ess at the same time. De-ess amount is controlled by a separate pot, and the Q and frequency choices that you make in the HMF are also used by the de-esser's opto limiter.
There are three distinctive and useful features in the compressor. The Blend control mixes the amount of compressed signal with the original and the FF/FB button offers a choice between either a modern feed-forward compressor style or feedback--common to vintage compressors of yesteryear. Thirdly, the Pre/Post button instantly jumps the equalizer's position in the Portico's chain from before to after the compressor.
The compressor uses a THAT Corp. VCA chip with 1:1 to 40:1 ratios, a -30dBu to +20dBu threshold, 20 to 75ms attack times, 100ms to 2.5-second release times, and up to 20 dB of make-up gain. An RMS/Peak button switches between RMS and peak detection, with RMS used below 250 Hz and peak on higher frequencies.
Output And Silk
The Output section has a control called Texture for the Silk and Silk+ modes that adds saturation to the output transformer by reducing the amplifier's negative feedback. Silk, indicated when the button glows blue, emphasizes low frequencies and Silk+ glows red and emphasizes high frequencies.
In II The Channel
The ability to have a mic, line and direct input always connected and ready to go is a big plus for me. The mic pre handles up to +26 dBu and also functions as a second line input without a pad.
The unit's lighted buttons are excellent in dimly lit control rooms, as are the positive-feeling rotary switches and the tactilely reassuring center-detent EQ boost/cut controls. The LED meters, although compact, are bright and easy to read from across the room.
My first check was running audio through the Portico II without any processing. Channel strips have no bypass, so I carefully matched levels and the monitoring volumes of a source going into the Portico and coming out at the same time. Drums, vocals, bass and guitars all sounded bigger and richer simply by passing through the Portico II.
The mic preamp compares favorably to a vintage Neve module. On vocals using a Neumann U87, the differences were nil as compared with a vintage 1073 with the EQ switched out. On the Portico II, hum and noise levels were lower and the dynamic range was much higher than the 40-plus-year-old 1073. Percussive sources sounded warmer in the low frequencies, yet very open in the highs.
The DI was immaculately clean and fat sounding. My Fender Strat sounded exactly like it should; its passive pickups were not loaded down, and there is plenty of gain if you want to drive the Portico II's compressor hard. Routing the highpass filter to the compressor sidechain prevented unwanted gain reductions from inadvertent palm thumps. When switching from a mic source to the DI, I liked not having to call up another I/O channel in Pro Tools.
The EQ Pre/Post button is extremely useful, especially for heavy processing. If you are looking to both brighten and squash a snare, changing the EQ's position to post-compressor will compensate for losing attack brilliance, which is caused by compression with fast attack times. Without the hassle of changing patch cords, I could make a "Pre/Post" check when searching for a sound.
The FF/FB button is like having two compressors in one. Feed-Forward is the mode best used for more aggressive control, obvious compressor effects, or for harder and more insistent sounds. And at about the same compression settings, FB had a vintage, smooth sound when I wanted dynamic modification that was less strictly enforced--more compression with fewer artifacts. As I would expect in FB mode, vocals were rounder and taller, using up more space in the mix; when using FF, the same vocal track became harder, more present and undeniable sounding.
Combinations of FF/FB and RMS/Peak modes make the compressor extremely versatile. In FF mode, at the same threshold setting as in FB, the RMS mode allowed louder attacks and deeper gain reductions on percussive sources like kicks, snares and tambourines. Selecting Peak in FB mode seems to speed attack times slightly by attacking more often, but it caused less LF compression. The Peak Detector mode was best for "peak stop"-type limiting for program mixes, pedal-steel guitar or loud singers with no mic technique.
The Blend knob is a great way to dial in the exact amount of overall dynamic control. No matter how much you squash, being able to add back the original sound to taste--all in phase is an excellent feature. The equalizer is great for everything from subtle touch-ups on full tracks and keyboards to shaping individual guitar tracks to fit into huge "wire choir" stacks. The Q range is perfectly designed for extreme carving of poorly recorded tracks all the way to subtly polishing an already great-sounding vocal track.
When used in moderation, the de-esser was gentle and generally all I needed for most well-recorded vocal tracks with few sibilance problems. Because the de-esser is a dynamic EQ, it also works for de-emphasizing a band of mid-range frequencies; you can somewhat reduce peaky vocal frequencies (where a singer sings certain notes much louder than the rest) or acoustic guitar resonances, or even loud hi-hat leakage on a snare drum track--all with minimal collateral sonic damage.
Finally, Silk and Silk+ are two cherries on top. Silk works well to warm up any thin-sounding instrument track--a kind of low-frequency boost--while Silk+ is a very high-frequency glossy effect useful for dulled-out, heavily compressed sounds.
Modern Rupert Neve Sound
The Portico II Channel offers the epitome of the Rupert Neve sound in a unit that is super-flexible and powerful, yet intuitive and simple to use. The Neve legacy lives on with this combination of his time-proven circuit topologies and newly designed processors for these modern times.
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