behringer 921B OSCILLATOR Oscillator Thomann Norway User Guide

behringer 921B OSCILLATOR Oscillator Thomann Norway

Specifications

• Product: 921B OSCILLATOR
• Type: Analog VCO Module for Eurorack
• Version: 3.0

Product Information

The 921B OSCILLATOR is a legendary analog VCO module designed for Eurorack systems. It features a range of controls for adjusting frequency and generating audio and sub-audio frequencies.

Usage Instructions

Safety Instructions

1. Read and follow all instructions provided in the manual.
2. Avoid exposing the apparatus to water, except for outdoor products.
3. Clean the unit only with a dry cloth.
4. Ensure ventilation openings are not blocked and install the unit as per manufacturer’s instructions.
5. Avoid placing the unit near heat sources like radiators, stoves, or amplifiers.
6. Use only attachments/accessories specified by the manufacturer.
7. Be cautious when using carts, stands, or tables to prevent tip-over.
8. Avoid installing the unit in confined spaces like bookcases.
9. Keep the unit away from naked flame sources.

Controls

• FREQUENCY: This knob manually adjusts the frequency in semitones for the 921B oscillator circuit, generating both audio and sub-audio frequencies.
• RANGE: Sets the general frequency range of the oscillator in octaves, adjustable by semitones with the FREQUENCY knob.
• 921AB LINK FREQ: Accepts frequency connectors for parallel wiring with 3.5mm TS connectors.

FAQ

Q: Where can I find warranty information for the 921B OSCILLATOR?
A: For warranty terms and conditions, as well as additional information, please visit community.musictribe.com/support.

Quick Start Guide
921B OSCILLATOR
Legendary Analog VCO Module for Eurorack

Safety Instruction

1. Please read and follow all instructions.
2. Keep the apparatus away from water, except for outdoor products..
3. Clean only with a dry cloth.
4. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
5. Do not install near any heat sources such as radiators, heat registers, stoves or other apparatus (including amplifiers) that produce heat.
6. Use only attachments/accessories specified by the manufacturer.
7. Use only specified carts, stands, tripods, brackets, or tables. Use caution to prevent tip-over when moving the cart/apparatus combination.
8. Avoid installing in confined spaces like bookcases.
9. Do not place near naked flame sources, such as lighted candles.
10. Operating temperature range 5° to 45°C (41° to 113°F).

LEGAL DISCLAIMER

Music Tribe accepts no liability for any loss which may be suffered by any person who relies either wholly or in part upon any description, photograph, or statement contained herein. Technical specifications, appearances and other information are subject to change without notice. All trademarks are the property
of their respective owners. Midas, Klark Teknik, Lab Gruppen, Lake, Tannoy, Turbosound, TC Electronic, TC Helicon, Behringer, Bugera, Aston Microphones and Coolaudio are trademarks or registered trademarks of Music Tribe Global Brands Ltd. © Music Tribe Global Brands Ltd. 2024 All rights reserved.

LIMITED WARRANTY

For the applicable warranty terms and conditions and additional information regarding Music Tribe’s Limited Warranty, please see complete details online at community. musictribe.com/support.

921B OSCILLATOR Controls

Controls

1. FREQUENCY – This knob manually adjusts the frequency in semitones for the 921B oscillator circuit. This oscillator can generate both audio and sub-audio frequencies for control or audio.

2. RANGE – This knob sets the general frequency range of the oscillator in octaves, numbered to match pipe organ notations, which can then be adjusted up or down by semitones with the FREQUENCY knob.

3. 921AB LINK FREQ – These parallel jacks accept frequency control voltage signals from a 921A module via cables with 3.5 mm TS connectors. The parallel wiring of the jacks also allows a control voltage signal to be sent through and back out to drive additional 921B modules.

4. 921AB LINK WIDTH – These parallel jacks accept 921A control voltage signals for the rectangular wave width parameter via cables with 3.5 mm TS connectors. The parallel wiring of the jacks also allows a control voltage signal to be sent through and back out to drive additional 921B modules.
   NOTE: If the 921B input voltage exceeds the range of 0 to +6 V, the excess voltage could result in the width being 0% or 100%, which means no waveform will be present at the square wave output until the control voltage is returned to the normal range. When using 921B with a 921A driver, the 921A’s WIDTH OF RECTANGULAR WAVE knob can offset the control voltage output from 921A to compensate. For example, when 921A’s WIDTH knob is set to 50%, the 921A’s normal control voltage range into 921B becomes -3 V to +3 V.

5. SYNC WEAK/OFF/STRONG – Use this switch to set how closely 921B follows the sync signal routed in via the SYNC IN jack. If the SYNC IN input is not required, select the center OFF switch position.

6. SYNC IN – Use this jack to route an external sync
   signal into the 921B module via cables with 3.5 mm TS connectors. A sawtooth waveform is recommended to produce the best sync results.

7. AC MOD – Use this AC-coupled input jack to control frequency modulation via a control signal.

8. DC MOD – Use this DC-coupled input jack to control frequency modulation via a control signal.

9. WAVEFORM OUTPUTS – Use these jacks to route oscillator signals out of the module via cables with 3.5 mm jacks. Four waveforms are available: sine, triangular, sawtooth and rectangular.

Power Connection

The 921B OSCILLATOR module comes with the required power cable for connecting to a standard Eurorack power supply system. Follow these steps to connect power to the module. It is easier to make these connections before the module has been mounted into a rack case.

1. Turn the power supply or rack case power off and disconnect the power cable.
2. Insert the 16-pin connector on the power cable into the socket on the power supply or rack case. The connector has a tab that will align with the gap in the socket, so it cannot be inserted incorrectly. If the power supply does not have a keyed socket, be sure to orient pin 1 (-12 V) with the red stripe on the cable.
3. Insert the 10-pin connector into the socket on the back of the module. The connector has a tab that will align with the socket for correct orientation.
4. After both ends of the power cable have been securely attached, you may mount the module in a case and turn on the power supply.

Installation

The necessary screws are included with the module for mounting in a Eurorack case. Connect the power cable before mounting.
Depending on the rack case, there may be a series of fixed holes spaced 2 HP apart along the length of the case, or a track that allows individual threaded plates to slide along the length of the case. The free-moving threaded plates allow precise positioning of the module, but each plate should be positioned in the approximate relation to the mounting holes in your module before attaching the screws.
Hold the module against the Eurorack rails so that each of the mounting holes are aligned with a threaded rail or threaded plate. Attach the screws part way to start, which will allow small adjustments to the positioning while you get them all aligned. After the final position has been established, tighten the screws down.

This procedure tunes the 921B OSCILLATOR module’s “octave scaling” to an exact 1 V/oct. calibration to facilitate precise control.

1. Power up the 921B module and allow it to warm up for a few minutes.

2. Prepare the following control settings on 921B:

   • Set the SYNC toggle switch to the center OFF position.
   • Set the RANGE switch to 2’.
   • Set the FREQUENCY control knob to exactly  on the scale.
   • Make sure no 921AB LINK FREQ jacks are connected.
     Note : All adjustment trimmers are accessible from the 921B module’s underside. Note the positions of the FREQ ADJ, SCALE, HI ADJ multi-turn trimmers and the OCT ADJ single-turn trimmer. Make sure you have suitable tools to adjust the trimmers if required.

3. Carry out an initial FREQUENCY control calibration by adjusting the FREQ ADJ trimmer so that the 921B sawtooth output shows exactly 640 Hz when checked with an accurate frequency meter.

4. Fine-tune the 921B oscillator’s low-frequency scaling via the following steps:

   • Make sure the FREQUENCY control knob remains at 0 on the scale during this procedure.
   • Apply exactly -2 V to a 921AB LINK FREQ input jack. (A 921A module can be used to supply the -2 V or use a similar low-impedance stable-voltage source.)
   • Trim the SCALE trimmer to set 160 Hz, then remove the -2 V input and readjust the FREQ ADJ trimmer to 640 Hz.
   • Repeat this cycle until both 160 Hz and 640 Hz are accurate to ±1 Hz when the -2 V is plugged in and out of the 921AB LINK FREQ input jack.

5. Fine-tune the 921B oscillator’s high-frequency scaling via the following steps:

   • With no 921AB LINK FREQ jack connected, check the frequency is still set for 640 Hz output, then apply exactly +5 V to the 921AB LINK FREQ input.
   • Trim the HI ADJ trimmer to set the 921B sawtooth output to exactly 20.48 kHz.
   • Re-check that 640 Hz is still correct when the +5 V input is removed.
   • Repeat as required.

6. Make a final fine-tune of the RANGE rotary switch scaling, if required, via the following steps:

   • With no 921AB LINK FREQ jack connected, check the frequency is still set to 640 Hz on the RANGE knob 2’ setting.
   • Set the RANGE switch to 32’ and adjust the OCT ADJ trimmer for 40 Hz at the 921B sawtooth output.
   • Re-check to make sure that 2’ = 640 Hz and adjust the FREQ ADJ trimmer if required.
   • Repeat as required.

Specifications

Signal Connections

1 V/16%

Input Impedance| 100 kΩ, unbalanced
Maximum input level| 0 V to +6 V
Width range| < 10% to > 90%
Sync input| 1 x 3.5 mm jack, AC coupled
Sync input impedance| 1.5 kΩ, unbalanced
Sync input lock range| ± 6 semitones
Sync input response| 10 Hz to 20 kHz, > -10 dBu
Maximum input level| +15 dBu
AC / DC mod input| 2 x 3.5 mm jacks, AC/DC coupled
AC / DC mod input impedance| 100 kΩ, unbalanced
AC / DC mod response| 10 Hz to 10 kHz, > -10 dBu
Maximum input level| +4 dBu
Waveform outputs| 4 x 3.5 mm jacks, mono
Waveforms| Sine, triangular, sawtooth, rectangular
Output Impedance| < 800 Ω, unbalanced
Output level| Typically -4 dBu
Controls

Frequency| 1 x rotary knob

±12 semitone, selectable

**** Range| 1 x rotary switch

LO / 32′ / 16′ / 8′ / 4′ / 2′,

selectable

Sync selector

| 1 x 3-position toggle switch

Weak / off / strong, selectable

Power|
Power supply| Eurorack
Current draw| 45 mA (+12 V),

45 mA (-12 V)

Physical|
Dimensions| 58 x 40 x 129 mm

(2.3 x 1.6 x 5.1″)

Rack units| 8 HP
Weight| 0.14 kg (0.31 lbs)

FEDERAL COMMUNICATIONS COMMISSION COMPLIANCE INFORMATION

Behringer
921B OSCILLATOR

Responsible Party Name: Music Tribe Commercial NV Inc.
Address: 122 E. 42nd St.1,
8th Floor NY, NY 10168,
United States
Email Address: legal@musictribe.com

FCC

921B OSCILLATOR
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.

Hereby, Music Tribe declares that this product is in compliance with Directive 2014/30/EU, Directive 2011/65/EU and Amendment 2015/863/EU, Directive 2012/19/EU, Regulation 519/2012 REACH SVHC and Directive 1907/2006/EC.
Full text of EU DoC is available at https://community.musictribe.com/
EU Representative: Music Tribe Brands DK A/S
Address: Gammel Strand 44, DK-1202 København K, Denmark
UK Representative: Music Tribe Brands UK Ltd.
Address: 8th Floor, 20 Farringdon Street London EC4A 4AB, United Kingdom

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.

References

• Music Tribe
• Music Tribe
• Music Tribe

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