Filters - Resonators

OVERVIEWEntirely dicrete VCA combined with a vactrol controlled low pass filter. The sound is gorgeous somewhere between wood and acid and the input stage can distort really well when desired. Did we already mention the lack or any ICs in the signal path? In best old school fashion this thing is bui..

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-101-6 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..

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..

Module A-108 is a completely new voltage-controlled low pass pass filter based on the well-known transistor ladder (Moog ladder). The module has internally an 8 stage low pass filter with different slopes available: 6, 12, 18, 24, 30, 36, 42 and 48 dB per octave. In addition it features an band pass..

Module A-120 is a voltage controlled low-pass filter, which filters out the higher parts of the sound spectrum, and lets lower frequencies pass through. The Cut-Off Frequency determines the point at which filtering takes effect. You can control this manually, or by voltage control (filter modulation..