Tags: VCF module

Notes: Dive deep into the world of sound manipulation with our Slimline Voltage Controlled Filter in a space-saving 2HP modular format. This module is ideal for all synthesizer lovers who are looking for intense and precise filter control in a compact design. Its powerful features allow you to shape your sounds with impressive detail.

Notes: Module A-106-5 is a 12dB multimode filter that is based on the filter circuit of the Oberheim SEM module.

The filter is equipped with a band pass output and a combined low/notch/high pass output. For this output a control knob defines the relation between low and high pass signal. If both signals appear at the same level (i.e. middle position of the Mix knob) one obtains a notch filter. Otherwise the low or high pass signal predominates.

The module does not feature self-oscillation in contrast to most of the other filters of the A-100 system.

The module generates a distorted audio signal if the level control is set to about 50% (i.e. centre position) or more with A-100 standard signals like VCOs.

Notes: A-101-6 is a new filter module that uses so-called opto FET's to control the filter frequency. Opto FET's are very similar to Vactrols, but use light dependent field effect transistors (FET's) instead of light dependent resistors (LDR's). An opto FET is a combination of a light-dependent FET and an LED, both put into a small light-proof case. The advantage, compared to vactrols, is a much faster response of opto FET's compared to LDR's - this allows much faster attack/decay times and even FM effects.

The variable resistors corresponds to the opto FET. The brightness of the Opto FET LED's, and consequently the filter frequency, can be adjusted manually (Frequ. control) and controlled by means of an external control voltage (CV) with attenuator. The LED at the front panel reflects the LED brightness inside the opto FET's.

The type of filter is chosen by jumpers on the PC board (factory setting: low pass). The type of filter determined by the jumpers positions can be marked by means of a water-resistant felt pen at the front panel.

The resonance is controlled by the Feedback control up to self-oscillation. By means of a trimming potentiometer the maximal feedback can be adjusted. High feedback values can be used mainly in the all-pass mode to obtain very extreme self-oscillation sounds. Even an external feedback signal can be used instead of the internal feedback connection (FB In socket). Whenever the filter type is changed by means of the jumpers the trimming potentiometer for the maximal feedback has to be re-adjusted.

The Mix control is used to pan between the original signal (CCW position) and the effect signal (CW position). In filter mode (LP/HP) this control is usually set fully CW. In the all-pass modes one obtains phasing sounds at centre position or "pure" all-pass sound in fully CW position.

Notes: What does this do?

This is an analogue filter based on the 1974 SEM filter. The original early design did not self oscillate into a sine wave. This one also does not self oscillate. The sound, however, makes up for that. You get the original notch sweep, and incredible band pass mode at such a low friendly price.

Added Features

-Onboard VCA
-Onboard envelope generator (decay)
-Variable trigger input circuit. Emulates a Vactrol.
-Dual audio input possible

Width: 10HP
Depth: 1 PCB stack, skiff compatible

Notes: HN VCF is a state variable filter having 12 db Low Pass, 12 dB High Pass, 6 dB Band Pass plus 18 db Low Pass marked as "LP!", because it has extra drive. All three parameters: "Freq", "Resonance" and "Drive" have dual knobs with outer knobs controlling bipolar CV amount. These affected CVs are then shown by the relative green/blue LEDs.

The possibility to have CV over "Resonance" and "Drives" makes it a very capable 6 HP filter.

"LP!" output has 6 dB steeper slope (18 dB) compared to ordinary 12 dB "LP" output. Plus it has much more drive.

Dimensions
6 HP
35 mm deep

Current Draw
55 mA +12V
65 mA -12V

Notes: The SetonixSynth Marsupial is a new dual filter design based around the re-issued AS3350 filter IC, originally used in rare synths such as the Synton Syrinx, Crumar Spirit and Rhodes Chroma but never widely utilized. Normalization between the control inputs and a Series/Parallel switch makes it simple to dial in a huge variety of unique and musical filter sounds.

Current draw: 36mA @ +12V; 35mA @ -12V

Eurorack width/depth: 8hp; 25mm

Notes: The Low Fat is a new 2hp Eurorack module by AJH Synth, it's a High Pass filter, with frequency control by either manual pot, and/or external CV with attenuator. It's intended to compliment other filters, particularly low pass VCF modules, in practical tasks such as removing excessive low frequencies, for example when the bass is swamping a mix. It can be switched between 6dB (1 pole) response and 12dB (2 pole) response.

By patching a CV signal to the FCV input it can be voltage-controlled and used musically as with any other VCF. When used in conjunction with a LP filter it forms a fully customisable band pass filter, allowing the range of passbands to be cherry-picked. Feeding in a 1V/Oct pitch CV and setting the FCV pot to a suitable level allows it to track an incoming pitch CV, so the amount of High Pass filtering remains constant as the pitch of the incoming VCOs traverse up and down the frequency range. This can be particularly useful in creating percussive sounds, such as snares and hats, but also on sequenced bass lines. Since it is only 2HP it's a great way to occupy one of those frustrating gaps in your eurorack modular case with something that is deceptively useful, and adds another dimension to the classic bass monster that is the Transistor Ladder Filter.

Dimensions:
2 HP
26 mm deep

Current Draw:
9 mA +12V
12 mA -12V
0 mA 5V

Notes: Belgrad is an all-analogue voltage controlled filter module which - on par with our other modules - brings something new to the table. While it can be used as a traditional VCF for "academic" subtractive synthesis, we guarantee countless hours of exciting timbral explorations thanks to its unique character, flexibility, and features. The most prominent feature is that it offers a multitude of frequency responses with two resonant peaks.

- Eurorack synth compatible
- 14HP, skiff friendly
- Current draw: +45mA / -42mA
- Reverse power protection