Scaling Processor

Scaling Processor is a compact, three-section voltage and audio utility inspired by the classic STS Scaling Processor found on the original CV Processor M-Class panel. Designed in the Serge tradition, this module focuses on clarity, flexibility, and hands-on control, making it an indispensable tool for shaping control voltages, audio signals, and modulation relationships in any 4U system.

The module provides three independent two-channel processing sections, each optimized for fast patching and intuitive signal conditioning. From simple attenuation and mixing to voltage range limiting and peak/trough extraction, Scaling Processors excels as a behind-the-scenes workhorse that quickly becomes central to complex patches.

A built-in stable +5V reference output is included for offsets, biasing, and quick utility duties anywhere in your system.

Key Features

• Three independent processing sections

• DC-coupled throughout (suitable for CV and audio)

• Bipolar attenuation on all controlled inputs

• Dedicated +5V reference output

• Serge-compatible 4U format and signal levels

Section Overview

Top Processor

• One bipolar attenuated input

• One non-attenuated input

• Single summed output

Ideal for quick scaling and mixing where one signal needs precise level control while another passes at unity gain.

Middle Processor

• One bipolar attenuated input

• One non-attenuated input

• Single summed output

Functionally identical to the top processor, allowing parallel or cascaded processing for more complex voltage shaping.

Bottom Processor

• Two bipolar attenuated inputs

• Dedicated ±5V offset control

• MIN output (lowest voltage of the two inputs)

• MAX output (highest voltage of the two inputs)

• SUM output (standard mixed output)

This section operates similarly to a classic Peak & Trough processor, enabling dynamic voltage comparison, range limiting, and logic-like CV behavior while still offering traditional mixing.

+5V Output

A precision +5V reference source is provided for:

• Adding fixed offsets

• Biasing CV paths

• Creating manual modulation sources

• Feeding processors that expect a known reference voltage

This voltage is internally stable and designed to be safely used throughout a Serge-style system. LOW-LGE030C-SCH

User Manual

Signal Compatibility

• Accepts audio and control voltages

• Designed for Serge-level signals

• Fully DC-coupled signal path

Attenuation Controls

All attenuated inputs are bipolar, allowing:

• Positive scaling

• Negative inversion

• Complete signal nulling

Center position corresponds to zero gain.

Offset Control (Bottom Processor)

The OFFSET knob introduces a variable DC voltage (±5V range) into the bottom processor’s signal path. This is especially useful for:

• Shifting LFOs into unipolar ranges

• Biasing random voltages

• Creating windowed modulation effects when combined with MIN/MAX outputs

MIN / MAX Outputs

• MIN outputs the lowest instantaneous voltage of the two inputs

• MAX outputs the highest instantaneous voltage of the two inputs

Common uses include:

• CV range limiting

• Envelope following and comparison

• Creating stepped or conditional modulation paths

• Generative and logic-style patches without digital logic

Patch Examples

Classic Scaling

• Patch an LFO into an attenuated input

• Use the output to precisely control modulation depth

Offset Random Voltages

• Patch a random source into the bottom processor

• Use OFFSET to shift the voltage range

• Extract MIN or MAX for constrained randomness

CV Logic / Windowing

• Patch two envelopes into the bottom processor

• Use MAX to select the dominant contour

• Use MIN for inverse or subtractive motion

Audio Mixing

• Mix two oscillators or waveforms

• Apply bipolar attenuation for phase inversion and blending

Design Notes

Scaling Processor follows the philosophy of the original Serge and STS utilities: simple building blocks that reveal deeper functionality through patching. Rather than prescribing behavior, the module encourages experimentation, making it equally valuable for beginners and experienced patchers.
Internally, the design adheres to proven Serge-style topologies and precision reference handling as shown in the module schematics, ensuring stable operation and predictable results in performance and studio environments.

DIY Build Documenation:

LGE030 Bill of Materials
LGE030 PCB Layout w/ Designators
LGE030 Main Board Schematic (Coming Soon)
LGE030C I/O Board Bill of Materials
LGE030C I/O Board Layout w/ Designators
LGE030C I/O Board Schematic (Wiring Diagram)

Mechanical Parts BOM generally required for building Low-Gain Electronics Modules

Calibration: Monitor Minimum Processor output with volt meter. Adjust Offset Trimmer so that it reads as close to 0V as possible.

Serge Modular Ecosystem Compatibility
Modern Serge-style 4U systems use two primary mounting standards: Loudest Warning–style and Random*Source–style.
Low-gain Electronics modules follow the Loudest Warning–style mounting format (unless stated otherwise) and are electrically
compatible with all Serge-style systems, though mounting (panels) and power adapters may be required for some installations.
Please contact us if you have further questions about this.