Rupert Neve Designs Shelford Channel

Important Safety Instructions

Please read and keep these instructions. Heed all warnings and follow all instructions. Do not use this apparatus near water and clean only with a dry cloth. Ensure ventilation openings are not blocked and install according to manufacturer's instructions. Avoid heat sources and do not defeat safety features of plugs. Protect power cords from damage. Use only manufacturer-specified attachments and accessories, and exercise caution when using carts to avoid tip-over. Unplug during lightning storms or long periods of disuse. Refer all servicing to qualified personnel. Do not expose to dripping or splashing, and do not place liquid-filled objects on the apparatus. Avoid overloading outlets. This apparatus requires a protective earth connection. The power switch is on the rear panel and should remain accessible. The mains plug or coupler serves as the disconnect device and must remain operable.

FCC/Canadian Compliance: This equipment has been tested and found to comply with Class B digital device limits, designed to provide reasonable protection against harmful interference. Changes or modifications not expressly approved by Rupert Neve Designs LLC could void the user's authority to operate the equipment. The apparatus does not exceed Class A/B radio noise emission limits set by the Canadian Department of Communications.

Noise Exposure Warning: Exposure to extremely high noise levels may cause permanent hearing loss. The U.S. Government's OSHA has specified permissible noise level exposures. To prevent potentially dangerous exposure, use hearing protectors when operating equipment capable of producing high sound pressure levels. The document includes a chart detailing permissible noise exposure durations and corresponding sound levels (dBA, Slow Response) with typical examples.

Warning Symbols: The lightning flash symbol with an arrowhead indicates the presence of uninsulated "dangerous voltage" that may constitute a risk of electric shock. The exclamation point symbol indicates important operating and maintenance instructions are present in the accompanying literature.

Shelford Channel User Guide

Thank you for your purchase of the Shelford Channel. This unit represents the definitive evolution of Rupert Neve's classic console modules, refined for the 21st-century studio. It features Rupert Neve's first new transformer-gain, class-A microphone preamplifier in over 40 years, an inductor EQ section, a Diode Bridge Compressor, variable Silk saturation, and a new dual-tap transformer output stage.

The Shelford Channel offers richly-colored tonal options and precisely-engineered controls, maintaining the soul of classic Rupert Neve designs with modern versatility.

Please note the safety concerns and power requirements before using this product.

Shelford Channel: Block Diagram

The block diagram illustrates the signal flow. Audio enters via MIC INPUT, DIRECT IN, or LINE INPUT. The signal passes through the MIC PRE (with controls for Phantom Power, Phase, Gain, Trim, HPF) and can be routed through the EQ (with controls for EQ In, Low Freq, LF Peak, Mid Hi Q, Mid, Mid Freq, HF Peak, 8k/16k, HF) either before or after the compressor. The compressor section includes controls for COMP IN, Threshold, Ratio, Timing, Blend, Make-Up Gain, Silk, Texture, and features like HPF to SC, Pre EQ, and SC Insert. The signal then proceeds to the MAIN OUTPUT, with options for a -6dB output and a VU Meter to display output level or gain reduction.

Shelford Channel: Front and Back Panels

Front Panel Controls: The front panel features:

• MIC/DI/LINE: Selects Mic/DI or Line input.
• THRU: Passive loop out for the DI input.
• HPF Freq: Selects the high-pass filter frequency.
• Trim: Provides +/- 6 dB gain adjustment.
• Signal: LED indicating signal presence (green) or near clipping (red).
• HPF: Engages the high-pass filter.
• EQ In: Engages all EQ bands except HPF.
• Low Freq: 4-position switch for low band EQ frequencies.
• Mid Freq: 6-position switch for mid band EQ frequencies.
• Mid Hi Q: Adjusts the Q width of the mid band.
• 8k/16k: Selects high band frequency between 8 kHz and 16 kHz.
• DI Jack: For direct injection or instrument inputs.
• GND Lift: Separates audio ground from chassis earth.
• Mic Gain: 12-position rotary switch for 0-66 dB gain.
• Phase: Inverts signal polarity.
• 48V: Engages phantom power for microphone input.
• LF: Adjusts low frequency EQ boost/cut.
• LF Peak: Selects between Shelf and Peak mode for LF EQ.
• Mid: Adjusts mid frequency EQ boost/cut.
• HF Peak: Selects between Shelf and Peak mode for HF EQ.
• HF: Adjusts high frequency EQ boost/cut.
• COMP IN: Engages the compressor.
• Threshold: Sets the compressor's threshold level.
• Ratio: Sets the compressor's slope.
• Timing: Selects compressor attack/release speed.
• Blend: Mixes compressed and uncompressed signals.
• Make-Up Gain: Adjusts output level after compression.
• Silk: Engages harmonic enhancement circuitry (Red/Blue modes).
• Texture: Fine-tunes the Silk circuitry.
• VU Meter: Displays output level or gain reduction.
• Peak LED: Indicates peak level reached.

Back Panel Connections:

• -6dB LINE OUT: Transformer-coupled, balanced output.
• SIDE CHAIN SEND/RETURN: For external processing of the compressor sidechain.
• LINK: For stereo linking of multiple units.
• LINE IN: Balanced line input.
• MIC IN: Transformer-balanced microphone input.
• AC Input: IEC connector for power.
• Chassis Ground Lift: Separates audio signal ground from chassis earth.

Detailed Control Descriptions

Input Controls

DI and Thru Jacks

These 1/4" jacks accept mic/direct injection (DI) or instrument/line inputs. Inserting a plug here bypasses the rear MIC input. They feature a 2.2 megohm input impedance for minimal source loading. Selecting 'Line' via the MIC/DI/LINE switch overrides these jacks.

MIC/DI/LINE Switch

Toggles between microphone/direct injection input (button out) and line input (button in).

Gnd Lift

This switch separates the direct connection from audio signal ground to chassis earth.

Signal Present LED

Indicates "Signal Presence" (minimum -20dBu) in green. Indicates 2-3dB below input stage clipping (+23 dBu) in red.

Mic Gain

A 12-position rotary switch controlling gain from 0 to 66 dB in 6 dB steps.

Trim

A detented potentiometer providing continuous gain adjustment over a +/- 6 dB range.

48V

Engages phantom power for the microphone input. It is recommended to mute or lower monitor/headphone levels before engaging +48V. Dynamic, ribbon, and some tube condenser mics do not require +48V, while most condenser mics do.

Phase

A push-button switch that inverts the polarity of the signal path. Illuminates when engaged. The symbol "Ø" is often used for opposite polarity.

HPF

Engages a 12dB/octave high-pass filter. The HPF potentiometer is variable from 20Hz to 250Hz, used to filter unwanted low frequencies or shape source material in conjunction with the EQ. Engaging the HPF to S/C switch routes the HPF to the compressor's side-chain.

HPF Freq

Selects the frequency (-3dB point) where the 12 dB/octave Bessel filter rolls off low frequencies. Designed to preserve timing information while reducing low-frequency noise. A lower setting is generally safer for recording.

EQ Controls

EQ In

Engages all EQ frequency bands except the HPF.

LF

Adjusts up to 15 dB of boost or cut at selected low frequencies. Can be used as a gentler alternative to the HPF. Reduce signal level to prevent clipping when boosting.

Low Freq

A 4-position rotary switch selecting corner or center frequencies for the low band EQ: 35 Hz, 60 Hz, 100 Hz, and 220 Hz.

LF Peak

When out, the LF band is in shelf mode (boost/cut diminishes above corner frequency at ~6dB/octave). When the HI PEAK button is pressed, the LF band switches to peak mode with a bell-shaped curve. Combined with LF FREQ, this offers 8 tonal variations for the low end.

Mid Hi Q

When out, the mid band's resonance (Q) at maximum boost is typically 2. When pressed, the Q narrows to approximately 3.5. The Q widens with less boost/cut, typical for passive EQ. The Q is asymmetrical: narrower for cuts than for boosts.

Mid

Adjusts up to 15 dB of boost or cut at selected mid frequencies. Reduce signal level to prevent clipping when boosting.

Mid Freq

A 6-position rotary switch selecting the center frequency of the mid band EQ: 200 Hz, 400 Hz, 900 Hz, 1.8 kHz, 3.5 kHz, and 7.5 kHz. The 200 Hz setting is useful for cuts in dense mixes.

HF Peak

When disengaged, the HF band is in shelf mode (~6dB/octave boost/cut above corner frequency). When the HI PEAK button is pressed, it changes to peak mode with a bell-shaped curve, utilizing inductor and capacitor circuits.

8k/16k

A switch that selects the high band center/corner frequency between 8 kHz (out) and 16 kHz (pressed). Combined with the HI PEAK switch, this offers 4 different EQ curves for the high frequencies.

HF

Adjusts up to 15 dB of boost or cut at selected high frequencies.

Compressor-Limiter Controls

THE SIDE CHAIN INSERT JACKS

These unbalanced jack pairs allow external EQ or processing of the compressor's side-chain signal. Changes in the side-chain affect compressor sensitivity. For example, cutting low frequencies in the side-chain makes the compressor less responsive to bass dynamics. Boosting high frequencies can make it sensitive to sibilance, acting as a de-esser. While unbalanced, they often work with balanced EQs.

Comp In

Engages the compressor section.

Threshold

Sets the level (-25 dB to +20 dB) at which the compressor begins to attenuate. Fully clockwise means minimal/no compression; counter-clockwise increases gain reduction.

Ratio

Sets the compression slope from 1.5:1 to 8:1. For example, a 3:1 ratio means a 15 dB signal rise over the threshold results in a 10 dB attenuation, allowing only a 5 dB output rise.

When setting Threshold and Ratio, the VU meter is helpful, but listening and using the "COMP IN" (Bypass) button for comparison is ultimately key.

SC Insert

Inserts an external device into the side-chain signal path via the rear panel jacks.

HPF to S/C

Routes the High Pass Filter into the compressor's side-chain. This reduces the compressor's sensitivity to low frequencies, which can cause excessive compression. It helps regulate perceived loudness by preventing low-frequency energy from triggering the compressor.

Gain

Known as Make-Up Gain, this control restores the output level after compression, compensating for the attenuation of peaks.

Timing

A six-position control adjusting the attack/release speed of the compressor. See page 18 for specific timing values.

Link

Links the side-chain control of multiple units for stereo operation.

Pre EQ

In normal operation, the compressor follows the EQ. Pushing the PRE EQ button reroutes the compressor ahead of the EQ. This can make EQ changes have a greater impact on output levels and compressor behavior. Adjusting Threshold after EQ is set is advisable.

Blend

Allows mixing of the uncompressed signal with the compressed signal. Fully counter-clockwise monitors the uncompressed signal (like bypass). Fully clockwise monitors the compressed signal. This feature offers flexibility not found on vintage compressors.

Fast

When pressed, this mode speeds up both attack and release times of the selected compressor time constant.

Compressor Settings Advice: Listen carefully to levels and mix values rather than relying on hearsay settings. View the compressor as a semi-automatic volume control and be aware of potential artifacts. Listen for changes in tonality from altering transient and plosive strength.

Output Controls

VU Select

Switches the VU Meter between output level and gain reduction metering.

Silk

Engages the "Silk-Red" or "Silk-Blue" circuitry to add harmonic content and saturation to the output transformer. "Silk Blue" emphasizes lows/low-mids, while "Silk Red" accentuates high-mids/highs.

Texture

Fine-tunes the "Silk" modes, allowing control over the amount of harmonic saturation, from absent to levels exceeding vintage products. These controls offer a wide range of tonal options.

VU Meter

Calibrated in dB to show either the final average output level or the amount of gain reduction.

Peak

An LED that illuminates when peak level has been reached.

Specifications

Mic Pre

• Input Impedance: 2200 Ohms
• Maximum Input: +21.5dBu from 150Hz to 22kHz; +8dBu 20Hz to 22kHz
• Gain Steps: 12 positions from 0 dB to 66 dB in 6 dB steps.
• Noise: Un-weighted, 22Hz-22kHz, source impedance 150 Ohms balanced: Main Out @ unity gain -100.9dBu; -6dB Out @ unity gain -106.6dBu; +30dB gain (Main Out) -91.37dBu; +66dB Gain (Main Out) -64.1dBu; Equivalent Input Noise -121.37dBu
• Frequency Response: +/-0.25dB from 17Hz to 45kHz

Direct Input

• Maximum Input: 8dBu @ 20Hz to 120kHz
• Noise @ Main Output: -100dBu (22Hz to 22kHz)

Line Input

• Maximum Input Level: +30.5dBu 20Hz to 30kHz
• Total Harmonic Distortion and Noise: @ 1kHz, +20dBu output level, no load: Better than 0.002%; @ 20Hz, +20dBu output level, no load: 0.05% Typical (2nd and 3rd harmonic)
• Noise @ Main Output: -101.1dBu (Un-weighted, 22Hz-22kHz, source impedance 40 Ohms balanced, no load.)
• Frequency Response: +/- 0.25dBu from less than 10Hz to 110kHz; -0.32dB @ 120kHz
• Maximum Output Level: +26dBu @ 16Hz to 20kHz
• Total Harmonic Distortion and Noise with SILK engaged:
  • RED: TEXTURE @ min: 0.0131% (mostly 3rd harmonic); TEXTURE @ max: 1.66% (mostly 2nd harmonic) at 100Hz, +20dBu input.
  • BLUE: TEXTURE @ min: 0.0079% (mostly 3rd harmonic); TEXTURE @ max: 0.941% (mostly 2nd harmonic) at 100Hz, +20dBu input.
• High Pass Filter: Continuously variable swept frequency from 20Hz to 250Hz. Slope: 12dB/Octave

EQ

• Noise: Un-weighted, 22Hz-22kHz, -92dBu

Signal Present / Overload Indicator

• Signal Present: Illuminates GREEN when input stage signal level reaches -20dBu
• Overload: Illuminates RED when input stage signal level reaches -23dBu

Diode Bridge Compressor

• Noise (BW 22Hz – 22kHz): 0 dB Makeup Gain: -84.5 dBu; +20 dB Makeup Gain: -64.2 dBu
• Time Constants: Measurements taken represent full range achievable between 1.5:1 Ratio and 8:1 Ratio setting using a 0 dBu I/P 1kHz Burst Tone.
  • Fast (TC1): Attack 180µS – 1.8mS // Release 100mS – 150mS
  • MedFast (TC2): Attack 750µS – 5.25mS // Release 160mS – 250mS
  • Med (TC3): 2.7mS – 18mS // Release 350mS – 525mS
  • MedSlow (TC4): 4.6mS – 38mS // Release 600mS – 1S
  • Slow (TC5): 11mS – 72.5mS // Release 800mS – 1.25 S
  • Auto (TC6): 5.75mS – 35.5mS // Release T1 400mS – 850mS, T2 TBD
  • "Fast" Mode Multiplier: Modifies aforementioned TC's by 70% of original value.

Frequency Response Charts

The following sections present graphical data from Audio Precision tests, illustrating the performance characteristics of the Shelford Channel across various settings and frequency bands. These charts detail the effects of EQ boosts and cuts, filter responses, and compressor timing.

• Low Frequency Peak Response: Graphs showing boost and cut curves for 35Hz, 60Hz, 100Hz, and 220Hz settings.
• Low Frequency Shelf Response: Graphs showing shelf boost and cut curves for 35Hz, 60Hz, 100Hz, and 220Hz settings.
• Mid-Band Low Q Frequency Response: Graphs illustrating boost and cut responses for mid-band frequencies (220Hz, 400Hz, 900Hz, 1.8kHz, 3.5kHz, 7.5kHz) with a low Q setting.
• Mid-Band High Q Frequency Response: Graphs illustrating boost and cut responses for mid-band frequencies (220Hz, 400Hz, 900Hz, 1.8kHz, 3.5kHz, 7.5kHz) with a high Q setting.
• High Frequency Peak Response: Graphs showing peak boost and cut curves for 8kHz and 16kHz settings.
• High Frequency Shelf Response: Graphs showing shelf boost and cut curves for 8kHz and 16kHz settings.
• HPF Frequency Response: Graphs showing the response of the high-pass filter at 20Hz and 250Hz settings.
• Texture Frequency Response: Graphs illustrating the effect of the Silk circuitry (Red and Blue modes at maximum texture) on the frequency response.

Product Warranty

Rupert Neve Designs warrants this product to be free from defects in materials and workmanship for a period of three (3) years from the date of purchase. The company agrees to remedy any defect identified within this period by repairing or replacing the product at its option.

Limitations and Exclusions

This warranty does not apply to products that have been improperly installed, misused, abused, damaged during shipping, damaged by batteries, or altered/modified. It extends only to the original end-user purchaser. Proof of purchase is required for warranty service. This express, limited warranty is in lieu of all other warranties. Rupert Neve Designs is not liable for special, incidental, or consequential damages. Some states may not allow these limitations.

Warranty Service

If a defect is suspected, contact Rupert Neve Designs technical support at 512-847-3013 or service@rupertneve.com for troubleshooting. If the device is malfunctioning, a Return Material Authorization will be issued with shipping instructions.

Model Number: 5035