Filters - Resonators

The updated "skiff friendly" design of the MML Filter now features bipolar "attenu-verters" for the CV controls as well as an all new RED MODE!This new mode activates a feedback distortion circuit capable of actually changing the pitch of the notes coming in to the filter in a musical way that adds ..

Module A-101-1 is a special multitype filter based on an idea by Nyle A. Steiner (published in Electronic Design, issue  25, December 1974, page 96 ff). The circuit uses the standard non-inverting amplifier filter design. Different filter types (low pass / LP, band pass / BP, high pass / HP) ar..

A-101-2 is a vactrol based combination of Low Pass filter (LP) and VCA and was inspired by the Buchla module 292. The term "Low Pass Gate" was created by Don Buchla and stands for a module that can be switched between low pass and VCA. The control (manually and via external CV) is responsible for fr..

A-101-6 is a new filter module that uses so-called opto FETs to control the filter frequency. Opto FETs are very similar to Vactrols but use light depending field effect transistors (FETs) instead of light depending resistors (LDRs). A opto FET is a combination of a light de..

Module A-102 is a reproduction of the legendary low pass filter design that uses diodes in the filter stage as frequency controlling elements resulting in "strange" resonance behaviour and frequency response as resonance and frequency are not independent from another.As for the rest the A-102 i..

Module A-103 is a voltage controlled low pass filter with 18dB/octave slope. The circuit is based on a modified transistor ladder (Moog ladder) and is a reproduction of the legendary TB303 filter.As for the rest the A-103 is identical to the A-120 Moog low pass filter (same controls, ..

A-104 is a fourfold formant filter as used in the Mixtur Trautonium by Oskar Sala.It is made of four parallel resonance filters, each filter can be switched to low pass or band pass or off. Frequency, resonance and level are controlled for each filter separately (no voltage control). The frequency r..

Doepfer A-105-2 24dB Low Pass (SSI-Type) FilterModule A-105-2 is a voltage controlled low pass filter with 24dB/octave slope. It is the successor of the A-105 which had to be discontinued because the obsolete SSM2044 filter circuit. The A-105-2 is based on the SSI2144 which is in turn the ..

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 colori..

Module A-106-1 has it's origin in our experiments to built a MS20 filter clone. The module is not exactly the same as the MS20 filter but similar. The famous original MS20 included two filters: a 12 dB lowpass and a 6dB high pass filter connected in series both with a very specia..

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 s..

Module A-106-6 is a multimode filter that is based on the filter circuit of the Oberheim Xpander. The module features 15 different filter types (those filters of the A-107 that were available in the Xpander) with 8 filters available simultaneously. The toggle switch Filter G..