Rupert Neve Designs Dual Diode Bridge Compressor

The harmonically rich tonality of the DualDiode Bridge Compressor is built to produce a wide range of colors – and built to help you make a statement with your music. Based on the dynamics circuit originally developed for the acclaimed ShelfordChannel, the 5254 is outfitted for dual mono or stereo use with Rupert Neve Designs’ customtransformers and class-A electronics, tailor made for a compact 1U 19” enclosure.

Fifty years after Mr. Rupert Neve created his first compressor designs, the Dual Diode BridgeCompressor reimagines the larger-than-life personality of these classic circuits with new levels ofprecision and control, enhanced creative power, and increased punch to your tracks, mixes, and masters.

The Diode Bridge
Where the VCA compressor found in the Portico II Channel and Master Buss Processor providesunmatched clarity, the weighty, harmonically rich tonality of diode bridge compression can be essential inpushing key sources like vocals, electric guitars, bass and drums to the forefront of a mix.

By understanding the limitations of the vintage units’ topologies, painstaking effort was taken to reproducethe unique tone of these classics while improving the noise floor, expanding inflexible time constants,adding full wave sidechain detection for improved dynamic response, and widening the range of thresholdand ratio controls. Delivering the powerful sound of these iconic designs with enhanced flexibility for themodern age, the Dual Diode Bridge Compressor is a dynamic tool equipped to make a bold statement onvirtually any mix or track.

Timing is Everything
The unified TIMING control consists of six selectable settings, carefully chosen for different applications –a major departure from the slow, fixed attack of the vintage units.

FAST and MF settings are designed tohelp clamp down on more transient signals like drums, plucked string instruments and fast vocals. MEDand MS have slightly slower attacks and releases which allow more transients through, while having aslightly longer recovery. Lastly, SLOW and AUTO are both significantly slower and feature complexnonlinear release times, with smoother, less audible level control.
FAST mode increases the speed of both the attack and release for each setting, also effectively doublingthe number of time constants from 6 to 12. The FAST mode also allows for a dramatic increase in speedas compared to the Dual Diode Bridge Compressor’s renowned ancestors, providing significantly moretonal & operational versatility.

Faster TIMING settings will generally lead to higher peak-to-peak control voltage ripple, and thereforeinduce more harmonic content, translating into more color in the main audio path. Slower TIMING settingswill smooth the control voltage significantly, and thereby reduce the harmonic content added to the audiopath, resulting in more transparent compression. It is also worth noting that due to the nature of thistopology, these time constants inherently adapt themselves slightly depending on several factors:compression ratio, threshold, and source material. This dynamically generated timing shift and harmoniccontent is what gives the Dual Diode Bridge Compressor its unique personality.

The Right Blend
Given the naturally colored sonic signature of the 5254’s diode bridge, this built-in parallel compressionability is especially useful. The BLEND control allows the user to inject smaller amounts of extremecompression into an otherwise unaffected signal, creating an enhanced yet natural sound that maintainsdynamic range with blendable color and punch.

Take Control
In addition to the TIMING control, the diode bridge compressor can be further manipulated by the RATIO,THRESHOLD, GAIN, S/C HPF, S/C INSERT and LINK controls. The RATIO control has six selectablepositions on the rotary switch and allows the user to set the slope of the compressor curve with ratios of1.5:1 through 8:1. The THRESHOLD control allows the user to adjust the point at which compressionbegins, ranging from -25dBu to +20dBu.

The GAIN control adds make-up gain ranging from -6dB to+20dB. The S/C HPF is 12dB/octave with continuously variable frequency control from 20Hz to 250Hz.This feature can be immensely useful for making the compressor respond less to the powerful – and oftenmore sustaining – low frequencies in a mix or instrument, which might otherwise give the compressor amore “mushy” response.

The SC INSERT is comprised of an always-active send and return for thecompressor side chain, which can be used to insert a more fine-tunable EQ to further sculpt thecompressor response, or as a way to insert a key signal into the return, controlling the compression via aseparate source to “duck” the signal when the key source is above the threshold. LINK connects thecontrol voltage between the two channels – so when one channel is triggered, it will trigger the otherchannel  equally. This can often help maintain a solid center image in a stereo source. Note: for stereosources, it is always worth auditioning the “unlinked” sound as well, as linking can sometimes clamp downon the effective stereo width when the compressors are triggered by one side.

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