Intellijel mVCF User manual

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µVCF Manual
µVCF
State Variable Filter
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Manual Revision: 2018.09.13
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Table of Contents
Table of Contents
Compliance
Installation
Installing Your Module
Overview
Features
Front Panel
Controls
Inputs and Outputs
Instructions
Technical Specifications
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Compliance
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This device 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.
Changes or modifications not expressly approved by Intellijel Designs, Inc. could
void the user’s authority to operate the equipment.
Any digital equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to radio
communications.
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This device meets the requirements of the following standards and directives:
EMC: 2014/30/EU
EN55032:2015 ; EN55103-2:2009 (EN55024) ; EN61000-3-2 ; EN61000-3-3
Low Voltage: 2014/35/EU
EN 60065:2002+A1:2006+A11:2008+A2:2010+A12:2011
RoHS2: 2011/65/EU
WEEE: 2012/19/EU
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Installation
Intellijel Eurorack modules are designed to be used with a Eurorack-compatible case and power
supply. We recommend you use Intellijel cases and power supplies.
Before installing a new module in your case, you must ensure your power supply has a free
power header and sufficient available capacity to power the module:
● Sum up the specified +12V current draw for all modules, including the new one. Do the
same for the -12 V and +5V current draw. The current draw will be specified in the
manufacturer's technical specifications for each module.
● Compare each of the sums to specifications for your case’s power supply.
● Only proceed with installation if none of the values exceeds the power supply’s
specifications. Otherwise you must remove modules to free up capacity or upgrade your
power supply.
You will also need to ensure your case has enough free space (hp) to fit the new module. To
prevent screws or other debris from falling into the case and shorting any electrical contacts, not
leave gaps between adjacent modules, and cover all unused areas with blank panels. Similarly,
do not use open frames or any other enclosure that exposes the backside of any module or the
power distribution board.
You can use a tool like ModularGrid to assist in your planning. Failure to adequately power your
modules may result in damage to your modules or power supply. If you are unsure, please
contact us before proceeding.
Installing Your Module
When installing or removing a module from your case
always turn off the power to the case and disconnect the
power cable. Failure to do so may result in serious injury
or equipment damage.
Ensure the 10-pin connector on the power cable is
connected correctly to the module before proceeding.
The red stripe on the cable must line up with the -12V
pins on the module’s power connector. The pins are
indicated with the label -12V, a white stripe next to the
connector, the words “red stripe”, or some combination of
those indicators.
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Most modules will come with the cable already connected but it is good to double check the
orientation. Be aware that some modules may have headers that serve other purposes so
ensure the cable is connected to the right one.
The other end of the cable, with a 16-pin
connector, connects to the power bus board of
your Eurorack case. Ensure the red stripe on
the cable lines up with the -12V pins on the
bus board. On Intellijel power supplies the
pins are labelled with the label “-12V” and a
thick white stripe:
If you are using another manufacturer’s power
supply, check their documentation for
instructions.
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Once connected, the cabling between the module and power supply should resemble the
picture below:
Before reconnecting power
and turning on your modular
system, double check that
the ribbon cable is fully
seated on both ends and
that all the pins are correctly
aligned. If the pins are
misaligned in any direction
or the ribbon is backwards
you can cause damage to
your module, power supply,
or other modules.
After you have confirmed all
the connections, you can
reconnect the power cable and turn on your modular system. You should immediately check that
all your modules have powered on and are functioning correctly. If you notice any anomalies,
turn your system off right away and check your cabling again for mistakes.
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Overview
The µVCF state variable filter features three simultaneous filter outputs: a 2-pole 12 dB/octave
low pass, a 2-pole 12 dB/octave high pass, and a 1-pole bandpass. It tracks 1 V/octave pitch
input over a wide range and can be used as a low-distortion sine VCO when self-resonating.
This is another great David Dixon design offering a very clean and precise filter. It responds very
well to frequency modulation and the small size makes it an ideal choice for a smaller system.
Features
● Low pass (LPF) 2-pole, high pass (HPF) 2-pole and bandpass outputs (BPF) 1-pole.
● FM1 input acts as 1V/Oct when fully clockwise. Tracks very well over 4+ octaves
● FM2 input has a bipolar attenuator
● At full Q the output produces very low distortion sine waves with a range of 2Hz to 20Khz
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Front Panel
Controls
1. FREQ - Sets the cutoff frequency of the filter. The knob
position is combined with the FM1 and FM2 inputs.
2. Q - Sets the resonance of the filter.
3. FM2 - Controls the amount and polarity of the FM2 input.
The input passes unmodified when the knob is fully
clockwise, inverted when fully counter-clockwise, and
has no effect when at the 12 o’clock position.
4. Input Attenuator - Attenuates the level of the filter input
signal. The signal is unattenuated when the knob is fully
clockwise.
5. FM1 Attenuator - Attenuates the control voltage of the
FM1 input. When fully clockwise the input is
unattenuated and tracks 1V / octave.
Inputs and Outputs
A. INPUT - Audio input to the filter.
B. FM1 - CV input for the cutoff frequency. Attenuation is
controlled by the FM1 Attenuator.
C. LPF - 2-pole (12 dB / octave) lowpass filter output.
D. FM2 - Another CV input for the cutoff frequency.
Attenuation / inversion is controlled by the FM2 knob.
E. BPF - 1-pole (12 dB / oct) bandpass filter output.
F. HPF - 2-pole (12 dB / oct) highpass filter output.
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Instructions
Start by plugging the signal that you want to be filtered into the IN input and turn up the Input
Attenuator until the signal reaches the desired volume level. Then, one of the LPF, BPF, or
HPF outputs and connect that to your VCA or main output. If you are fairly new to eurorack and
filters, using a white or pink noise signal may be helpful to gain a better understanding of the
different filter types and their effect.
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Adjusting the FREQ knob will change the frequency range passed by the filter, and increasing
the Q knob will add resonance at the FREQ cutoff frequency. Now try connecting a modulation
source like an LFO or envelope to FM1 and/or FM2. Adjust the FM1 Attenuator and FM2 knob
to dial in your desired amount of modulation. The FM1 input will track melodies if the FM1
Attenuator is turned fully counter clockwise, and if Q is fully counter clockwise the µVCF will
output a sine wave with no input connected.
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Technical Specifications
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Width
6 hp
Maximum Depth
21 mm
Current Draw
25 mA @ +12V
24 mA @ -12V
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