Quick Start Guide904A VOLTAGE CONTROLLEDLOW PASS FILTER
Legendary Analog Low Pass VCFModule for Eurorack
Controls
- 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 the voltage received from the control inputs.
- 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.
- REGENERATION – This knob varies the amount of internal feedback, creating a resonant peak at the cutoff frequency. At higher settings this becomes self-oscillation.
- SIGNAL INPUT – Connect the incoming signal via 3.5 mm TS cable.
- SIGNAL OUTPUT – Send the processed signal to another module via 3.5 mm TS cable.
- 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
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.
- Turn the power supply or rack case power off and disconnect the power cable.
- 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.
- 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.
- 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 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 is aligned with a threaded rail or threaded plate. Attach the screws partway 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 | +1-6 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 kO, unbalanced |
| Maximum input level | +10 dBu |
| Signal Output | |
| Type | 3.5 mm jack, AC coupled |
| Impedance | 1 kO, 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 kit 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 Ibs) |
LEGAL DISCLAIMERMusic Tribe accepts no liability for any loss which may be suffered by any person who relies either wholly on 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, Oberheim, Auratone,Aston Microphones and Coolaudio are trademarks or registered trademarks of Music Tribe Global Brands Ltd. © Music Tribe Global Brands Ltd. 2021 All rights reserved.
LIMITED WARRANTYFor the applicable warranty terms and conditions and additional information regarding Music Tribe’s Limited Warranty, please seecomplete details online at musictribe.com/warranty.
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/SAddress: Ib Spang Olsens Gade 17, DK – 8200 Aarhus N, Denmark
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