For the past two decades, Rupert Neve Designs has delivered a steady stream of innovative and powerful analog audio processors, including the Master Buss Processor [Tape Op #89], the Master Bus Transformer, and the Shelford, Newton, and Portico series. Naturally, my interest was piqued when I heard about their newest release, the OptoFET dual stage compressor. This single rack space, single channel unit combines two distinct yet interlinked compressor circuits: one FET and one optical (Opto). I spent a few weeks putting a pair of these beauties through their paces to discover what they could do.
The front panel features RND’s familiar colored aluminum knobs and illuminated pushbuttons, complemented by three meters and several indicator LEDs. Despite the number of controls – 13 knobs and 12 switches – the layout never feels crowded, and the controls are easy to read and access. The rear panel keeps things simple as well, with XLR I/O, an IEC power inlet with mains switch, and a ground-lift toggle.
Feature wise, this box delivers everything you could hope for in a modern analog compressor. Starting from the left, an Input knob provides positive or negative gain for the electronically balanced input stage. Next, the FET section provides wide-ranging control via Attack, Release, Threshold, output Gain, and wet/dry Blend knobs. Pushbuttons handle FET bypass, a 125 Hz sidechain high-pass filter, Ratio selection (4:1 or 8:1), and Grit – more on that later. A horizontal bargraph meter displays gain reduction (in dBs) clearly and responsively. On the right side, the Opto compressor section mirrors the FET layout but with slower Attack characteristics, selectable Ratio of 2:1 or 5:1, and a Bloom mode. Together, the two sections form a pair of full-featured compressors in series, each offering sidechain high pass filter, wet/dry blend, and harmonic enhancement capabilities. The final Output feeds into a hefty output transformer, which provides total galvanic isolation in addition to some nice color before the OptoFET starts clipping (around +23 dBu).
Between the two compressor sections lies a simple but effective routing matrix, and that’s where this unit’s flexibility is realized. The order of the processors can be flipped – Opto into FET or vice versa. But wait – a variable-frequency Crossover can also be engaged, reconfiguring the compressors as parallel processors with either the Opto affecting the low frequencies and the FET controlling the highs or the opposite. A clever arrangement of indicator LEDs clearly displays the routing configuration of the compressors. This makes for lots of routing options to consider!
Many RND processors include the beloved Silk modes, but the OptoFET provides some slightly different coloring options. The FET section’s Grit processor does not simply add harmonics – it fundamentally changes the compressor’s behavior. In use, this allows the FET to range from clean control to wildly distorted, pumping effects. On the Opto side, Bloom imparts a subtle boost in mostly even harmonics, producing a warmth and smoothness reminiscent of the Blue Silk mode found on other RND units.
One obvious application of the OptoFET is on vocals. Dial in a bit of peak control with the FET section and some smoothing and thickness with the Opto to perfectly place the vocal in the mix, with as much character as you desire. Should the Opto follow or precede the FET? Good question – with the OptoFET, you can try both at the push of a button. Alternatively, use the crossover to apply the FET to shape the presence and attack while gently reining in low frequencies with the Opto. While mixing rock vocals, I found the FET set to 4:1 with fast attack and release times invisibly tamed transient peaks, while the Opto with a 2:1 ratio, slow attack, and fast release smoothed the overall dynamics. No Grit or Bloom was needed, as the compressors already added just the right amount of thickness. Grit, along with the Blend control, could certainly add a wide range of distortion if appropriate.
On drum bus, and especially on snare tracks, engaging the FET with Grit added an impressive amount of tone and energy. Another great sound was achieved with the Opto applied below 300 Hz and the FET above, effectively splitting duties between low-frequency density and high-frequency punch. This compressor can operate transparently or push drums or other instruments right to that White Stripes–style, hairy-edge-of-destruction saturation. For both electric and upright bass, I found that splitting the Opto for the lows and the FET for the highs allowed for a wide range of compression styles – from smooth, acoustic-friendly control to aggressive, distorted squashing. In every case, the OptoFET delivered results that would make any bass player grin.
One feature conspicuously missing from the OptoFET is stereo linking. That omission might raise some eyebrows, but in practice I didn’t find it to be a problem. While mastering a jazz quartet album featuring pianist Bill Cunliffe, I used two units across the stereo mix and matched their settings in Opto mode with a 50 ms attack, slow-ish release, 2:1 ratio, and Bloom engaged. Around 2 dB of gain reduction delivered just enough control and low midrange richness. Thanks to the detented knobs, matching the two units was straightforward, and using test tones I confirmed the levels’ behavior between the two units matched extremely well. I ultimately mastered the entire album through the pair, occasionally adding the FET section (before the Opto) at 4:1 with moderate time constants for added peak level control.
The OptoFET invites comparison to the classic Universal Audio 1176 and LA-2A combination. In most cases, I’m confident it can stand in for that revered pairing and achieve very similar – if not more flexible – results. The OptoFET exceeds the ranges of those classics with its expanded routing, sidechain flexibility, and Blend controls. Each compressor sounds excellent on its own, but together they unlock an extremely powerful and musical tool. Plus, the OptoFET’s noise floor was never a consideration, even in mastering, which can’t be said for many vintage analog units. The OptoFET is a rare processor that can live equally well on a vocal, on instruments, on a mix bus, or in the mastering chain.