Behringer System 55 Complete Eurorack Modular Synthesizer User Manual

1. Introduction

Welcome to the user manual for your Behringer System 55 Complete Eurorack Modular Synthesizer. This system is an authentic reproduction of a legendary 1970s modular synth, designed to provide a comprehensive and powerful platform for sound synthesis. It features 38 discrete all-analog modules, offering a vast array of sonic possibilities.

This manual will guide you through the setup, operation, maintenance, and troubleshooting of your System 55, ensuring you can fully explore its potential.

Figure 1: The Behringer System 55 Complete Eurorack Modular Synthesizer, showcasing its extensive array of modules across two interconnected Eurorack cases.

2. Important Safety Instructions

Please read and follow all safety instructions to prevent electric shock, fire, or injury. Keep this manual for future reference.

• Do not open the unit. No user-serviceable parts inside. Refer servicing to qualified personnel.
• Do not expose this appliance to rain or moisture.
• Do not use this apparatus near water.
• Clean only with a dry cloth.
• Do not block any ventilation openings. Install in accordance with the manufacturer's instructions.
• Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
• Protect the power cord from being walked on or pinched, particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
• Only use attachments/accessories specified by the manufacturer.
• Unplug this apparatus during lightning storms or when unused for long periods of time.

3. Setup

3.1 Unpacking and Inspection

Carefully unpack your Behringer System 55. Inspect the unit for any signs of damage that may have occurred during transit. If any damage is found, contact your dealer immediately.

3.2 Assembling the System

The System 55 is housed in two Behringer Eurorack Go cases. These cases need to be ganged together using the included brackets. Align the two cases carefully and secure them with the provided hardware. While possible to do alone, having a second person assist can make the process easier and ensure proper alignment.

3.3 Power Connection

Connect the power supply to the designated power input on the Eurorack cases. Ensure the power switch is in the OFF position before connecting to a power outlet. Once connected, you can switch the unit ON.

3.4 Initial Cabling

The System 55 is a modular synthesizer that requires patch cables for signal routing. You will need 3.5mm TS (Tip-Sleeve) patch cables for connecting modules within the system. For connecting the system's output to an external mixer or audio interface, you will find 3.5mm male to 6.5mm (quarter-inch) male cables useful, as the mixer module outputs are 3.5mm.

4. Operating the Behringer System 55

4.1 Understanding Modular Synthesis

Modular synthesizers operate by connecting individual modules together using patch cables to create complex signal paths. Each module performs a specific function (e.g., generating sound, filtering, modulating). Experimentation with patching is key to exploring the vast sonic landscape of the System 55.

4.2 Key Modules Overview

The System 55 includes a comprehensive set of modules:

• Oscillators (901A, 901B, 921, 921A, 921B): These modules generate the fundamental waveforms (sine, triangle, sawtooth, square) that form the basis of your sound. The 921A and 921B are often used in combination. Note that for the 921A/921B combo, if you intend to use the square wave, you must connect the width control; otherwise, the default width will be very narrow (5-10%) instead of the expected 50%.
• Filters (914 Fixed Filter Bank, Voltage Controlled Low Pass Filter, Voltage Controlled High Pass Filter): Filters shape the timbre of the sound by removing or emphasizing certain frequencies. The 914 Fixed Filter Bank offers a range of fixed frequency bands.
• Amplifiers (Voltage Controlled Amplifier): VCAs control the amplitude (volume) of a signal, often modulated by an envelope generator.
• Envelope Generators: These modules generate control voltages that change over time, typically used to shape the amplitude of a sound (ADSR: Attack, Decay, Sustain, Release) or other parameters.
• Sequential Controller: A step sequencer that generates a series of control voltages or gates, useful for creating melodic patterns or rhythmic modulation.
• MIDI-to-CV Converter: Allows the System 55 to be controlled by external MIDI devices, translating MIDI signals into control voltages (CV) and gate signals.
• Utility Modules (Control Voltages, Dual Trigger Delay, Attenuators, Interface, Sequential Switch): These modules provide essential functions like signal mixing, splitting, inverting, and logic operations, crucial for complex patching.

4.3 Patching and Sound Design Basics

The System 55 utilizes both V-trig and S-trig gate formats. Be mindful of the specific requirements of each module when patching gate signals. The system also provides fixed +/- 6V voltage outputs, which can be used to bring oscillators outside of the control range provided by their panel interfaces, allowing for broader frequency manipulation.

Start by connecting an oscillator to a VCA, and then an envelope generator to the VCA's control input. Connect the VCA's output to an audio output module, and finally to your mixer or audio interface. This forms a basic sound path. From there, introduce filters, modulators, and other modules to sculpt your sound.

5. Maintenance

5.1 Cleaning

Clean the exterior of the System 55 with a soft, dry cloth. Do not use abrasive cleaners, waxes, or solvents. Ensure no liquids enter the module jacks or controls.

5.2 Storage

When not in use for extended periods, store the System 55 in a dry, dust-free environment. Disconnect the power supply. If transporting, ensure the cases are securely closed and protected from impact.

6. Troubleshooting

6.1 Common Issues

• No Sound: Check all patch cable connections. Ensure the power supply is connected and the unit is turned on. Verify that the VCA is receiving both an audio signal and an envelope/gate signal. Check output levels on the mixer module.
• Unexpected Sound/Behavior: Review your patching. Modular synthesis can be complex, and unintended connections can lead to unusual results. Ensure all module controls are set as desired.
• Module Not Responding: Ensure the module is properly seated in its Eurorack slot and that its power connection is secure. Check if the module requires specific input signals (e.g., a gate signal for an envelope generator to trigger).
• Square Wave Sounds Thin (921A/921B): As mentioned in Section 4.2, ensure the width control is patched if you are using the square wave output from the 921A/921B oscillator combination.

If you encounter persistent issues, consult online resources, community forums, or the official Behringer support channels for more detailed assistance.

7. Specifications

8. Warranty and Support

For detailed warranty information, please refer to the warranty card included with your product or visit the official Behringer website. Warranty terms and conditions may vary by region.

If you require technical support or have questions not covered in this manual, please contact Behringer customer support through their official website or your local distributor. When contacting support, please have your product model (System 55) and serial number ready.