904A - Synthesizer BEHRINGER - Free user manual and instructions

Product Type	Eurorack Synthesizer Module
Module Width	12 HP
Module Depth	30 mm
Power Consumption	50 mA (+12V), 30 mA (-12V)
Main Function	Voltage-Controlled Low-Pass Filter (VCF)
Cutoff Frequency Range	20 Hz – 20 kHz
Resonance Control	Adjustable up to self-oscillation
Inputs	CV Cutoff, CV Resonance, Signal In (3.5 mm)
Outputs	Signal Out (3.5 mm)
Controls	Cutoff, Resonance, CV Attenuator
Construction	Aluminum front panel, steel chassis
Power Connector	10-pin Eurorack ribbon cable
Weight	Approx. 120 g
Operating Temperature	0°C – 40°C
Country of Origin	China
Warranty	3 years limited warranty
Repairability	Module designed for easy access; spare parts available
Cleaning	Use a dry cloth; avoid liquids

Frequently Asked Questions - 904A BEHRINGER

What is the Behringer 904A?

The Behringer 904A is a Eurorack module that emulates the classic Moog 904A voltage-controlled low-pass filter. It offers a cutoff frequency control and resonance with CV inputs.

What power supply does the 904A require?

It requires a standard Eurorack power supply with +12V and -12V rails. Typical consumption is 50 mA on +12V and 30 mA on -12V.

How do I connect the 904A to my modular system?

Use the included 10-pin ribbon cable to connect to your Eurorack bus board. Ensure correct orientation: red stripe indicates -12V.

Can the 904A self-oscillate?

Yes, turning up the resonance control past a certain point will cause the filter to self-oscillate, producing a sine wave output.

What are the CV inputs for?

The CV Cutoff input modulates the filter cutoff frequency, and CV Resonance modulates the resonance. An attenuator adjusts the CV amount.

What is the response curve of the filter?

It features a classic 24 dB/octave low-pass response, characteristic of the Moog ladder filter design.

Is the 904A compatible with other Eurorack modules?

Yes, it is fully compatible with any Eurorack system using standard 3.5 mm patch cables and CV/gate signals.

How do I clean the module?

Disconnect power and wipe the front panel with a dry, lint-free cloth. Do not use any liquids or sprays.

What is the warranty period?

Behringer offers a 3-year limited warranty covering defects in materials or workmanship. Keep your receipt.

Where can I find the user manual?

The user manual is available for free download on the Behringer website or through notice-facile.com.

USER MANUAL 904A BEHRINGER

Legendary Analog Low Pass VCF Module for Eurorack

Controls

VOLTAGE CONTROLLED LOW PASS FILTER FIXED CONTROL VOLTAGE 1 2 3 4 5 FREQUENCY RANGE 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 0 10 1 0 9 1 0 8 1 0 7 1 0 6 1 0 5 1 0 4 1 0 3 1 0 2 1 0 1 SIB IN SIB OUT CONTROL INPUTS 90 kA behringer 6

FIXED CONTROL VOLTAGE – Also referred to as "cutoff frequency", this knob manually determines the frequency above which frequencies are attenuated. The resulting frequency will depend on this knob's setting as well as voltage received from the control inputs.

2 FREQUENCY RANGE – Select one of 3 frequency bands in which the fixed control voltage operates. Position 1 is 1 Hz to 5 kHz, position 2 is 4 Hz to 20 kHz, and position 3 is 16 Hz to 80 kHz.

3 REGENERATION – This knob varies the amount of internal feedback, creating a resonant peak at the cutoff frequency. At higher settings this becomes self-oscillation.

4 SIGNAL INPUT – Connect the incoming signal via 3.5 mm TS cable.

5 SIGNAL OUTPUT – Send the processed signal to another module via 3.5 mm TS cable.

6 CONTROL INPUTS – Connect control voltage signals from other modules to affect the cutoff frequency. The sum of the voltage received doubles the frequency cutoff point for each 1 V increase.

Power Connection

P1 Red Stripe P2 2 1 10 9 400 mm ±10 15 16 +0V ±0 +12V GROUND -12V +12V GROUND -12V Connect end P1 to the module socket Connect end P2 to the power supply

The 904A 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.

Specifications

Controls
Fixed control voltage +/-6 V, summed with CV inputs
Frequency range selector	1 = 1 Hz to 5 kHz,24 dB per octave
	2 = 4 Hz to 20 kHz,24 dB per octave
	3 = 16 Hz to 80 kHz,24 dB per octave
Regeneration Off to full feedback
Signal Input
Type 3.5 mm jack, DC coupled
Impedance 10 kΩ, unbalanced
Maximum input level +10 dBu
Signal Output
Type 3.5 mm jack, AC coupled
Impedance 1 kΩ, unbalanced
Maximum output level +10 dBu
Output noise <-78 dBu, 22 Hz - 22 kHz
Control Inputs
Type 3 x 3.5 mm jacks, summed
Impedance 100 kΩ, unbalanced
CV range 1 V / octave,	12-octave range
Power
Power supply Eurorack
Current draw 65 mA (+12 V),	50 mA (-12 V)
Physical
Dimensions 40 x 129 x 38 mm	(1.6 x 5.1 x 1.5")
Rack units 8 HP
Weight 0.10 kg (0.22 lbs)

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, Auratone and Coolaudio are trademarks or registered trademarks of Music Tribe Global Brands Ltd. © Music Tribe Global Brands Ltd. 2019 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 musictribe.com/warranty.

Zhongshan Eurotec Electronics Limited

No. 10 Wanmei Road, South China Modern Chinese Medicine Park, Nanlang Town, 528451, Zhongshan City, Guangdong Province, China