OVERVIEW

The Serpent Audio SB4001 is a stereo VCA bus compressor designed specifically for the Karno SEPIA platform, combining classic mix-bus behaviour with modern control and tonal flexibility. Its quad VCA architecture delivers exceptional stereo accuracy and stability, while wide threshold and ratio ranges allow everything from subtle glue to assertive compression.

Engineered for professional hybrid and analogue workflows, the SB4001 integrates advanced sidechain filtering, stepped and adaptive release modes, internal parallel compression and optional harmonic drive. With its flat frequency response, true bypass switching, and ±16 V power rails, it offers transparent operation when required – or characterful impact when pushed – all within a recallable SEPIA module environment.

KEY HIGHLIGHTS

Quad VCA Stereo Precision

A four-VCA gain-reduction topology ensures tight stereo imaging, consistent tracking and reliable bus compression across complex programme material.

Classic Dynamics, Modern Control

Six ratios, ten attack times, stepped and adaptive release modes, plus variable release control, provide both vintage time constants and contemporary envelope shaping.

Advanced Sidechain Shaping

Selectable high-pass filters, boost and slope modes, and an external key input give detailed control over how the compressor responds to low-end energy and rhythmic content.

Harmonic Colour & Parallel Blend

Grind mode introduces valve-inspired harmonic saturation, while the wet/dry blend enables internal parallel compression for punch without loss of dynamics.

SEPIA-Optimised Integration

Designed exclusively for the Karno SEPIA system, with true bypass switching and high-headroom ±16 V rails for seamless integration into modular studio workflows.

FEATURES

• Stereo VCA bus compressor designed specifically for the Karno SEPIA module
• Quad VCA gain reduction architecture for enhanced stability and precision
• Classic bus-compressor envelope with stepped attack and release options
• Alternate auto-release mode for program-dependent dynamics control
• Variable release control for fine envelope shaping
• Grind harmonic mode for valve-inspired saturation and density
• Wet/dry blend stage for internal parallel compression
• High-pass filtered sidechain for low-frequency control
• Additional sidechain boost and slope modes for advanced detection shaping
• External key input for creative sidechain processing
• True bypass switching for instant A/B comparison

TECHNICAL SPECS

Type: VCA Bus Compressor

Channel Configuration: Stereo

Gain Reduction Topology: Quad VCA

Threshold Range: –20 dB to +20 dB

Ratio Range: 1.5:1 to 10:1

Attack Times: 10 selectable settings

Release Options: Stepped release settings, variable release, and auto release

Frequency Response: ±0.11 dB, 20 Hz – 20 kHz

Sidechain Filters: 60 Hz, 90 Hz, 120 Hz

Sidechain Modes: Boost mode, Slope mode

Sidechain I/O: 1 × 1/4″ external key input

Parallel Compression: Internal wet/dry blend control

Bypass: True bypass

Power Supply Rails: ±16 V DC

Module Format: Karno SEPIA compatible module