Pope Audio DIRTY-C SEPIA Module

The Pope Audio Dirty-C Sepia Module is a mono analogue chorus processor powered by ±15 V DC rails, designed for Karno Sepia modular systems and built to reproduce the modulation topology, headroom and tonal density of the Roland RE-501 chorus while expanding it with modern performance controls, blend management and instrument-level interfacing.

Authentic RE-501 Modulation Architecture

Dirty-C Sepia uses the same multi-delay analogue modulation structure that defined the RE-501 chorus, delivering dense stereo-imaging behaviour within a mono signal path that produces wide perceived spatial spread, strong harmonic animation and a natural sense of movement that remains musically anchored even at extreme modulation depths. The circuit preserves the soft transient rounding, upper-mid shimmer and low-frequency solidity associated with tape-era modulation while maintaining modern stability and noise performance.

Expanded Rate and Depth Control

The module introduces continuously variable rate and depth controls that allow the modulation engine to move from slow dimensional widening through to fast vibrato-style pitch displacement and unstable spectral warping. Rate determines the speed of modulation cycles while depth governs pitch excursion, allowing the unit to function as a thickening processor, animated ensemble effect or extreme motion generator.

Blend Control and Hi-Z Instrument Input

A dedicated mix blend control allows continuous balancing between dry and modulated signals, enabling precise placement within complex modular signal chains or direct instrument processing. The integrated hi-Z input allows guitars, basses and other high-impedance sources to interface directly with the module without external buffering, preserving transient detail and harmonic integrity.

Three Modulation Modes

Dirty-C Sepia offers three selectable modulation engines that reinterpret the original chorus circuit in different harmonic directions. Vibrato mode produces fully wet pitch modulation for liquid movement, microtonal drift and warped tape character. RE501 mode recreates the original chorus voicing, delivering dimensional thickening, shimmering movement and subtle spatial bloom. Ring Mod mode reshapes the modulation topology into aggressive spectral motion, introducing metallic sidebands, animated overtones and three-dimensional instability for experimental sound design.

Power and System Integration

The module operates on ±15 V DC rails to deliver wide dynamic range, strong transient headroom and stable analogue performance within Karno Sepia modular environments. Mono channel architecture ensures compatibility with modular routing schemes while preserving the spatial illusion created by the modulation network.

Why Choose Dirty-C Sepia

• Adds depth, motion and harmonic richness to static modular voices

• Allows direct connection of guitars and line instruments into a modular system

• Delivers authentic tape-era chorus character with modern reliability

• Moves seamlessly from subtle width enhancement to radical spectral animation

• Expands creative modulation options without adding digital artefacts

• Mono analogue chorus processor designed for Karno Sepia modular systems
• ±15 V DC rail operation for extended dynamic range and headroom
• Authentic RE-501 modulation topology
• Continuously variable rate control
• Continuously variable depth control
• Blend control for dry and effected signal balancing
• Hi-Z instrument input for direct guitar and bass connection
• Vibrato mode for full wet pitch modulation
• RE501 mode for classic chorus voicing
• Ring Mod mode for metallic and experimental spectral motion

This item, like everything we supply, comes with the complete support of our expert team. Our excellent technicians have been specifying, building and supporting studios for over twenty years. If you have any problems with installation, setup or everyday use, they’re never more than a click away, and always happy to help.

You can contact them here.