modular systems » Eurorack modules » sound processors » filters & resonators

Comb filter with knobs as well as CV inputs for cutoff frequency, resonance and feedback damping. The module's results range from soft, Phaser-like colorations to harsh, metallic effects. The basic character is rather cold. With the help of a white noise source, you can generate string sounds.

Comb filter with knobs as well as CV inputs for cutoff frequency, resonance and feedback damping. The module's results range from soft, Phaser-like colorations to harsh, metallic effects. The basic character is rather cold. With the help of a white noise source, you can generate string sounds.

Extremely versatile resonant filter with six bandpass filters/resonators which have a variable frequency and can even be tuned to scales!! These can be modulated ... and all of a sudden the SMR starts to live, to hover, to move chord structures.
All that with an incredibly fluid, beautiful, organic, deep sound ... and even in sync to the beat!

Besides of this you can use it as a tunable 6-band EQ, for pinging/plucking/striking and thus for creating percussive sounds or to quantize audio to certain scales. With two SMRs you can create a vocoder.

In our eyes and ears this was the highlight of both 2015's NAMM and Musikmesse!

Advanced low-pass design – The Discrete Core Ladder VCF shines with crisp sound, a very low noise-floor and a multitude of technical gimmicks. The module features a three-channel input mixer with saturation capabilities. Four outputs provide audio material filtered with -6 dB, -12 dB, -18 dB and -24 dB edge steepness. Each connector is phase-shifted by 90 degrees compared to the prior socket. Cutoff and resonance are voltage controllable. While self-oscillating, the filter can be played chromatically. This means, that the Discrete Core Ladder VCF is usable as a quadrature VCO as well. Thanks to a boost knob, the bass fundament can be kept intact at high resonance settings. A high-pass filter in the feedback path allows users to alter the resonance behavior. Compared to Moog’s classic Ladder design, the sound of the ACL circuit is considerably rougher. Saturation effects lead to roaring results. Tip: Be sure to try out filter FM patches!

The Dual State Variable VCF consists of two multimode filters with high-pass, band-pass, notch and low-pass outputs. The circuits feature an edge steepness of -12 dB per octave. Routing options allow serial or parallel connection. Thanks to normalizations and a total of three cutoff potentiometers, stereo material can be processed as comfortably as mono signals. Furthermore, a well-known feature from the Oberheim SEM synthesizer was implemented in the Dual State Variable VCF: The notch characteristic can be weighted more to the high-pass or low-pass side.
The basic character of the Dual State Variable VCF is rather soft, yet full-bodied. The resonance sounds extraordinarily rich and wet, even high values never sound all too harsh. While self-oscillating, the filters can be played like sine oscillators. By modulating both circuits in opposite direction, users are able to achieve interesting stereo effects.

Following the ADDAC103 T-Networks this new module is inspired by it’s simplicity. This is a 4 voice Square Oscillator with VCA, FM switch and a slew decay for the incoming Trigger IN. All voices are then sent through a Multimode Filter.

The ADDAC module 603 is a fully voltage controllable triple bandpass filter based on the modern version of SSM2164 from CoolAudio for pristine sound quality. The three filters are normalised allowing to be used either for the same input source or to process three independent sources. Each filter features a switchable slope of -6dB or -12dB, a phase inverter and high input gain to create soft to hard distortions. Additionally each filter output has a VCA to allow volume modulations and a feedback knob so that each filter could self-oscillate.

The 611 is a bandpass filter with a three-channel mixer at the input section. - The module is not exactly meant for precise audio processing, but rather a specialist for beefy tube saturation and distortion. - That's also why there is a mix control (dry / wet).

The Fixed Filter Bank 914 from AJH Synth is based on the sought after 914 Fixed Filter Bank from the 1960’s Moog 900 series modular synthesiser system. The design was revisited and adapted for eurorack.

The Fixed Filter Bank 914 from AJH Synth is based on the sought after 914 Fixed Filter Bank from the 1960’s Moog 900 series modular synthesiser system. The design was revisited and adapted for eurorack.

The Gemini 2412 is a smooth and fat sounding dual filter based on the circuits of Oberheim’s SEM. In addition to high-pass, band-pass and low-pass, the module features a variable mode, which allows you to crossfade between several filter types. The resonance is, at least subjectively, a little more aggressive than known from the SEM. Thus, the Gemini 2412 can sound more vigorous. Thanks to routing and jointly used modulation options, it is possible to flexibly combine both filter channels.

The Gemini 2412 is a smooth and fat sounding dual filter based on the circuits of Oberheim’s SEM. In addition to high-pass, band-pass and low-pass, the module features a variable mode, which allows you to crossfade between several filter types. The resonance is, at least subjectively, a little more aggressive than known from the SEM. Thus, the Gemini 2412 can sound more vigorous. Thanks to routing and jointly used modulation options, it is possible to flexibly combine both filter channels.

The backbone of a modular synthesizer is made up of modules that are as simple as possible with specific functions and a wide range of applications thanks to their linear behaviour and simplicity. The Lunar Module is the other extreme: A composition of several subfunctions that pursue a concrete goal. Namely: To make everything that runs through it sound as if it were radioed from a spacecraft to the earth via space-ground transmission. And the whole thing in the 70s.

Reinvention of a classic – The DH-ADSR is based on the envelope design of Moog’s Minimoog synthesizer. However, in terms of functionality, AJH’s module exceeds the vintage instrument’s circuits by far. The modulator offers a complete ADSR characteristic with addable Delay section and Hold stage. Two control ranges for all time-sensitive parameters allow detailed editing of short, percussive sounds as well as slowly evolving atmospheres. A re-trigger option makes it possible to employ the circuit as a complex LFO. Results can be tapped off a normal and an inverted output. Despite all this additions, behavior and curve shapes of the DH-ADSR resemble the Minimoog a lot. – An expressively playable, very musical envelope.

Reinvention of a classic – The DH-ADSR is based on the envelope design of Moog’s Minimoog synthesizer. However, in terms of functionality, AJH’s module exceeds the vintage instrument’s circuits by far. The modulator offers a complete ADSR characteristic with addable Delay section and Hold stage. Two control ranges for all time-sensitive parameters allow detailed editing of short, percussive sounds as well as slowly evolving atmospheres. A re-trigger option makes it possible to employ the circuit as a complex LFO. Results can be tapped off a normal and an inverted output. Despite all this additions, behavior and curve shapes of the DH-ADSR resemble the Minimoog a lot. – An expressively playable, very musical envelope.

Version in vintage black design

Faithful clone of the early Minimoog lowpass filter with all transistor pairs selected and matched by hand what was nt the case with the later Minis. The circuitry runs internally with exactly the same operational voltages and the transistors have the same specifications as 45 years ago. AJH Synth added voltage control of reconance and selectable overdrive.

Faithful clone of the early Minimoog lowpass filter with all transistor pairs selected and matched by hand what was nt the case with the later Minis. The circuitry runs internally with exactly the same operational voltages and the transistors have the same specifications as 45 years ago. AJH Synth added voltage control of reconance and selectable overdrive.

Version in black vintage design

The Sonic XV is a -24dB per octave steep diode filter with voltage controllable resonance. The filter circuit originates in the less-known vintage synthesizer Musonic Sonic V which has a quite different character from transistor ladder filters. The module features addtionally a 6dB low pass and a band pass output as well as voltage controllable wave shapers at the audio intput and in the resonance loop (!)

The Sonic XV is a -24dB per octave steep diode filter with voltage controllable resonance. The filter circuit originates in the less-known vintage synthesizer Musonic Sonic V which has a quite different character from transistor ladder filters. The module features addtionally a 6dB low pass and a band pass output as well as voltage controllable wave shapers at the audio intput and in the resonance loop (!)

Mum M8 is a low-pass with distinctive sound. It was modelled after the filter circuit known from the Akai S950 sampler. Compared to the original, the module offers various enhancements, including a resonance parameter, several CV inputs and an integrated VCA with clipping. Despite the new functions, the sound has remained classic. If you like classic drum & bass, jungle and breakbeat records, you’ll love the Mum M8.

This low pass filter is a very good -24dB/octave Moog filter, based on the classic Moog cascade with selected, low-noise transistors.

The new RS-100N version features all the improvements from the RS-100S regarding stability, tracking, distortion behavoiur and also the frequency range. Thanks to a new front panel and bus concept, this version of the RS-100 is fully compatible to Doepfer-style Eurorack systems.

This low pass filter is a very good -24dB/octave Moog filter, based on the classic Moog cascade with selected, low-noise transistors.

Being the successor of the RS-100, the new "S" version features several improvements regarding stability, tracking, distortion behavoiur and also the frequency range.

The RS-110 is a resonant analog multimode filter with excellent sound, resonance and four simultaneously available filter types. An insert function in the feedback loop allows you to insert other audio processors.
Thanks to a new dual-bus concept, this circuit is fully compatible to Doepfer’s Eurorack standard.

The RS-110N is a resonant analog multimode filter with excellent sound, resonance and four simultaneously available filter types. An insert function in the feedback loop allows you to insert other audio processors.

The RS-110N is a resonant analog multimode filter with excellent sound, resonance and four simultaneously available filter types. An insert function in the feedback loop allows you to insert other audio processors.
Thanks to a new dual-bus concept, this circuit is fully compatible to Doepfer’s Eurorack standard.

Filterbank module with eight fixed filter frequencies, each one octave apart. It is the successor of the RS-210 which was based on a rare 70ies filter bank from EMS. The newer version has different frequencies for a wider frequency range and the filter have a higher slope.

The RS360 Vocal / Phase Filter contains three voltage controlled resonant multimode filters that are summed at the outputs. The low pass and high pass filters with a slope of -24db/octave whilst the band pass and notch filters work with -12dB slope. The module is suited for creating vocal-like sounds and formants.

Genuine EMS Synthi filter. This legendary filter can be switched between pre 1974 and post 1974 filter type and response. For the first time response can be voltage controlled which was designed on the circuit board but not available on the matrix. This module is made under license from EMS.
Thanks to a new dual-bus concept, this circuit is fully compatible to Doepfer’s Eurorack standard.

Genuine EMS Synthi filter. This legendary filter can be switched between pre 1974 and post 1974 filter type and response (aka resonance). For the first time response can be voltage controlled which was designed on the circuit board but not available on the matrix. This module is made under license from EMS.
Thanks to a new front panel and bus concept, this version of the RS-500 is fully compatible to Doepfer-style Eurorack systems.

Voltage controlled multi mode filter of state variable topology. Not only being small in size but also sounding very tasty and unique. The slopes are rather flat with -12 and -6dB, providing for a rather smooth sound, unless you actvate the switches for the special parameters for resonance character and overdrive, as it will get wild, gnarly and dirty.

Befaco's dual low/high pass filter BF-22 is inspired by the filter of the early MS-20 which is based on the Sallen-Key filter topography. The tendency of sound is obvious- the filter freaks out, screams and is pretty dirty. The resonance is more present than in the original, though and thanks to befaco it is voltage controllable.
The two filters can be used individually and connected in series.

The Noise VCA not only consists of a noise generator and a VCA, but an analog multimode filter as well. In combination with one or two external envelopes, you get a full-blown drum and percussion voice. Add a VCO plus maybe an LFO and you have a full-blown mini synthesizer. The VCF has a a very precise feel to it.The noise generator can also be used as a random CV source. In version 2 the arrangement has changed: the polarizer button VCF-CVin has been replaced by a potentiometer switch combination. Furthermore, Q can now be turned up to self-resonance, the 1V/oct. tracking has been improved and the VCA lin mode has been refined.

The DMF-2 module consists of two identical filters with two modes: lowpass and a quasi-bandpass which are available simultaneously at separate outputs. Each filter works selectively with different filter slopes and allows overdriven sound by saturation. By lots of in- and output combinations the module can be used as two independent filters or as a parallel dual filter.

We currently do not accept pre-orders for Cwejman products. If you are interested in this module, please use the availability notification. The number of Cwejman circuits is limited. Therefore, we recommend you to order online IMMEDIATELY when a module becomes available. Enquiries via e-mail or telephone are usually not fast enough. (More detailed information can be found on the product page.)

The successor of the dignified MMF-1 bases on its capabilities as a ultra-clean multi-mode filter with seven selectable filter types and two slopes, expanding it by voltage controllable saturation with compression and second harmonic emphasis, then a MIX parameter for fine timbre tuning between original and processed distorted sound or a VCA at the output. The module combines the clear sound of the old MMF-1 with the saturated timbre of the MMF-6.

We currently do not accept pre-orders for Cwejman products. If you are interested in this module, please use the availability notification. The number of Cwejman circuits is limited. Therefore, we recommend you to order online IMMEDIATELY when a module becomes available. Enquiries via e-mail or telephone are usually not fast enough. (More detailed information can be found on the product page.)

The module Cwejman MMF-2 is a stereo multimode filter. It can be used as a true stereo filter or like two independent filters. Besides the cwejman´esque clean sound the filter has a switchable saturation stage allowing you for creating distorted wild sounds. Lots of filter types, voltage controlled parameters and also the dry/wet parameter make this filter a complex tool for sound processing.

We currently do not accept pre-orders for Cwejman products. If you are interested in this module, please use the availability notification. The number of Cwejman circuits is limited. Therefore, we recommend you to order online IMMEDIATELY when a module becomes available. Enquiries via e-mail or telephone are usually not fast enough. (More detailed information can be found on the product page.)

The Cwejman MMF-6 is a flexible multi-mode filter with six simultaneously available filter types at individual outputs. Besides the clear sound known from Cwejman the module also has "saturated" outputs for a nice nasty sound. Way cool!

We currently do not accept pre-orders for Cwejman products. If you are interested in this module, please use the availability notification. The number of Cwejman circuits is limited. Therefore, we recommend you to order online IMMEDIATELY when a module becomes available. Enquiries via e-mail or telephone are usually not fast enough. (More detailed information can be found on the product page.)

The big, sorry HUGE brother of the great RES-4 even outperforms it's concept by far. This module are four ultra stable multimode filters / resonators with three different resonance modes, three switchable filter types (plus a fixed notch), individual in- and outputs per filter and the Master section known from the RES-4 plus dry/wet controls.
What a monster module for filter and resonator use, generating drum sounds, equalizing etc.

We currently do not accept pre-orders for Cwejman products. If you are interested in this module, please use the availability notification. The number of Cwejman circuits is limited. Therefore, we recommend you to order online IMMEDIATELY when a module becomes available. Enquiries via e-mail or telephone are usually not fast enough. (More detailed information can be found on the product page.)

The RES-4 is a voltage controllable quad resonance filter. It bases upon Cwejman´s VC-EQ module but features explicitely greater parameter ranges and thus it is possible to create somewhat extreme sounds. An awesome module.

We currently do not accept pre-orders for Cwejman products. If you are interested in this module, please use the availability notification. The number of Cwejman circuits is limited. Therefore, we recommend you to order online IMMEDIATELY when a module becomes available. Enquiries via e-mail or telephone are usually not fast enough. (More detailed information can be found on the product page.)

Vactrol-based multimode filter based on a schematic by Nyle Steiner. Separate inputs for lowpass, bandpass and highpass.

Vintage edition with black faceplate and custom knobs.

Vactrol-based multimode filter based on a schematic by Nyle Steiner. Separate inputs for lowpass, bandpass and highpass.

Vactrol based combination of resonant 12dB lowpass filter and/or VCA. Inspired by the Buchla 292.

Vintage edition with black faceplate and custom knobs.

Vactrol based combination of resonant 12dB lowpass filter and / or VCA. Inspired by the Buchla 292.

Like any module of the 101-X series also Opto VCF resorts to opto-electronic parts but in this case so-called Opto-FETs are used instead Vactrols which have a avery different behaviour. The module consists of six 6dB filter stages arranged in series. Each stage can act individually as lowpass, highpass or as one of two all-pass filters. Plenty of options to experiment with, from usual filtering to phase shifting effects due to all-pass filters.

Reproduction of the legendary british diode lowpass filter. Resonance is possible up to self-oscillation but the behavior changes with the cutoff-frequency.

18dB low pass filter based on a modified Moog cascade. Resonance goes up to self-oscillation. The module sounds similar to the TB-303.

Based on the formant filter form the Trautonium the A-104 offers four resonant filter, switchable between low pass and band pass. Especially in band pass mode is good for creating static resonances, formats and vocal sounds.

The A-105 is a 24dB low pass filter that bases on the SSM 2044 chip that was used amongst others in following units: Korg Polysix, Korg Mono/Poly, Fairlight II, PPG Wave 2.2 und 2.3, Emu SP-1200, Siel DK600, Siel Opera 6. The first Prophets used the SSM2040 - the precedessor of the 2044 - that generates a very similar sound. The filter convinces with a very powerful sound. The resonance starts quite early to color the signal and makes a big range of sounds possible up to self-oscillation. The latter provides a very clean sine wave - no wonder, because the SEM2044 chip wasn´t designed only as a filter core but also as a sine wave oscillator.

The A-105-4 is a quad filter for polyphonic patches. It is based on the SSM2044 / SSI2144 chip, meaning the same component used in Korg Polysix, Mono/Poly, Fairlight II, PPG Wave, Emu SP-1200 and many other classic synthesizers. The filter has a very rich sound character. Its resonance begins coloring the sound rather early. High settings lead the module into self-oscillation. Then, the A-105-4 emits clean sine waves. Thanks to a gain stage at the input, signals can be distorted before reaching the filter. On top of that, there are lots of CV inputs for modulation purposes.

More than a MS-20 filter clone! X-tremly flexible 12dB lowpass and 6dB highpass with separate ins for the filters and endless combinations of how to mix the filters and their polarities. An extreme, exceptional and experimental module with very strange behavior!

Another filter that uses the circuitry of a classic. This time it´s the Oberheim SEM (Synthesizer Expander Module), that was used in the Four-Voice and Eight-Voice for instance. The filter has a saturated fat sound and especially in lowpass mode it growls in the bass range, very mighty and powerful. The very sensitive audio input allows distortion of the audio signal which forms the sound even more.