Behringer 921B OSCILLATOR User Manual

1. Introduction

This manual provides essential information for the proper installation, operation, and maintenance of your Behringer 921B OSCILLATOR module. The 921B is a vintage-sounding Voltage Controlled Oscillator module designed for Eurorack systems, faithfully reproducing the circuitry from the classic "Modular 55 & 35" Series.

Please read this manual thoroughly before using the module to ensure safe and optimal performance.

2. Important Safety Instructions

To reduce the risk of electric shock, fire, or damage to the module, always observe the following safety precautions:

• Power Supply: Only connect the module to a Eurorack power supply that meets the required specifications (typically +12V, -12V, +5V). Ensure the power supply is off before connecting or disconnecting the module.
• Ventilation: Ensure adequate ventilation around the module. Do not block any ventilation openings.
• Moisture: Do not expose this apparatus to rain or moisture. Do not place objects filled with liquids, such as vases, on the apparatus.
• Heat: Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
• Servicing: Do not attempt to service this product yourself. Refer all servicing to qualified service personnel.
• Cleaning: Clean only with a dry cloth.

3. What's in the Box

Upon opening the packaging, please verify that all components are present and in good condition:

• Behringer 921B OSCILLATOR Module
• Power Cable (Ribbon Cable for Eurorack)
• Mounting Screws
• Quick Start Guide / Safety Information (this manual)
• Bag (as per product specifications)

Figure 3.1: Front view of the Behringer 921B OSCILLATOR product box.

Figure 3.2: Side view of the product box, displaying an image of the 921B OSCILLATOR module.

4. Product Overview

The Behringer 921B OSCILLATOR is a core component for analog synthesis, providing rich and versatile waveforms. It is designed to integrate seamlessly into your Eurorack modular system.

Figure 4.1: Front panel of the 921B OSCILLATOR module, showing all controls and patch points.

Figure 4.2: Angled view of the 921B OSCILLATOR module, highlighting its compact Eurorack form factor.

Key Features:

• Vintage-sounding VCO module from the '70s era.
• Can be controlled via the 921A OSCILLATOR DRIVE module, or used as a free-running LFO.
• Authentic reproduction of the circuitry from the "Modular 55 & 35" Series.
• Separate audio outputs for each of the four waveforms: sine, triangular, sawtooth, and rectangular.

5. Setup

The 921B OSCILLATOR is a Eurorack module and requires a compatible Eurorack case with a power supply.

5.1. Installation into a Eurorack Case:

1. Power Off: Ensure your Eurorack case's power supply is completely turned off before proceeding.
2. Locate Space: Find an available space in your Eurorack case that accommodates the module's width (14 HP).
3. Connect Power: Connect the included ribbon cable to the 921B module's power header. Ensure the red stripe on the ribbon cable aligns with the -12V pin on both the module and your Eurorack power bus board. Incorrect connection can damage the module.
4. Mount Module: Carefully place the module into the desired position in your Eurorack case. Align the mounting holes with the rails.
5. Secure Module: Use the provided screws to secure the module to the Eurorack rails. Do not overtighten.
6. Power On: Once the module is securely installed and powered correctly, you may turn on your Eurorack case's power supply.

6. Operation

The 921B OSCILLATOR provides a range of controls for shaping its output waveform and frequency.

6.1. Controls and Inputs/Outputs:

• FREQUENCY Knob: Adjusts the fundamental frequency of the oscillator. This is a fine-tune control.
• RANGE Switch: Selects the octave range of the oscillator (32', 16', 8', 4', 2'). This acts as a coarse frequency control. The 'LO' setting allows the oscillator to operate at sub-audio rates, functioning as an LFO (Low Frequency Oscillator).
• SYNC Switch (WEAK/STRONG): Selects the type of synchronization.
  • WEAK: Resets the oscillator phase at each sync pulse.
  • STRONG: Forces the oscillator to restart its cycle at each sync pulse, regardless of its current phase.
• SYNC IN Jack: Input for external synchronization signals.
• AC MOD Jack: Input for AC-coupled modulation signals, typically used for vibrato or frequency modulation (FM).
• DC MOD Jack: Input for DC-coupled modulation signals, typically used for pitch control (e.g., from a keyboard or sequencer).
• Waveform Outputs (Sine, Triangle, Sawtooth, Rectangular): Dedicated outputs for each of the four primary waveforms generated by the oscillator. Connect these to other modules for further processing.
• WIDTH Jack: Input for modulating the pulse width of the rectangular waveform.
• 921AB LINK FREQ Jack: This jack is used to link the frequency control with a Behringer 921A OSCILLATOR DRIVE module for combined control.

6.2. Basic Patching Examples:

• Simple Tone: Connect any of the waveform outputs (e.g., Sine) to an audio mixer or VCA (Voltage Controlled Amplifier) in your Eurorack system, then to your audio interface or speakers.
• Pitch Control: Connect a CV (Control Voltage) output from a keyboard or sequencer to the DC MOD input to control the pitch of the oscillator.
• Frequency Modulation (FM): Connect an LFO or another oscillator's output to the AC MOD input to create FM effects.
• Pulse Width Modulation (PWM): Connect an LFO or envelope generator to the WIDTH input to dynamically change the timbre of the rectangular waveform.

7. Specifications

8. Troubleshooting

If you encounter issues with your 921B OSCILLATOR, consider the following common troubleshooting steps:

• No Sound/Incorrect Pitch:
  • Check power cable connection: Ensure the ribbon cable is correctly oriented (red stripe to -12V) and securely connected to both the module and the bus board.
  • Verify power supply: Confirm your Eurorack case's power supply is on and providing stable power.
  • Check patch cables: Ensure all audio and CV cables are securely connected to the correct inputs and outputs.
  • Adjust Frequency/Range: Make sure the FREQUENCY knob and RANGE switch are set to an audible range.
  • Check modulation sources: If using DC MOD, ensure the incoming CV is within the expected range.
• Unstable Pitch:
  • Allow warm-up time: Analog oscillators can take a few minutes to stabilize after being powered on.
  • Check power supply stability: A fluctuating power supply can cause pitch instability.
  • Environmental factors: Extreme temperature changes can affect analog circuitry.
• No Sync Response:
  • Verify sync signal: Ensure the signal patched into the SYNC IN jack is a strong, clean gate or trigger signal.
  • Check SYNC switch: Experiment with both WEAK and STRONG sync settings.

If problems persist, consult the Behringer support website or contact their customer service.

9. Maintenance

The Behringer 921B OSCILLATOR is designed for reliable operation with minimal maintenance.

• Cleaning: Use a soft, dry cloth to clean the module's front panel. Do not use abrasive cleaners, solvents, or waxes.
• Environment: Keep the module in a clean, dry environment, away from direct sunlight, excessive dust, and extreme temperatures.
• Connections: Periodically check all power and patch cable connections to ensure they are secure.

10. Compliance Information

This section details the regulatory compliance of the Behringer 921B OSCILLATOR module.

Figure 10.1: Federal Communications Commission (FCC) and CE Compliance Information.

10.1. Federal Communications Commission (FCC) Compliance:

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation.

If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

This equipment complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) This device must accept any interference received, including interference that may cause undesired operation.

Important Information: Changes or modifications to the equipment not expressly approved by Music Tribe can void the user's authority to use the equipment.

10.2. CE Mark Compliance:

Hereby, Music Tribe declares that this product is in compliance with General Product Safety Regulation (EU) 2023/988, Directive 2014/30/EU, Directive 2011/65/EU and Amendment 2015/863/EU, Directive 2012/19/EU, Regulation 519/2012 REACH SVHC and Directive 2007/23/EC.

Full text of EU DoC is available at https://community.musictribe.com/

10.3. Disposal Information:

Correct disposal of this product: This symbol indicates that this product must not be disposed of with household waste, according to the WEEE Directive (2012/19/EU) and your national law. This product should be taken to a collection center licensed for the recycling of waste electrical and electronic equipment (EEE). The mishandling of this type of waste could have a possible negative impact on the environment and human health due to potentially hazardous substances that are generally associated with EEE. At the same time, your cooperation in the correct disposal of this product will contribute to the efficient use of natural resources. For more information about where you can take your waste equipment for recycling, please contact your local city office, or your household waste collection service.

11. Warranty and Support

For detailed warranty information, please visit https://community.musictribe.com/pages/support or contact your local Behringer distributor.

For additional learning resources and product information, you can visit the Behringer website or scan the QR code on the product packaging:

Figure 11.1: Product box side showing the "Learn" QR code.

Scan this QR code for more information: https://qr.music-group.com/gluc