Doepfer A-105-4 Quad Poly VCF
- Order number: 180277
- Depth: 50
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.
The A-105-4 is a quadruple low-pass filter based on the SSM2044 / SSI2144. It features an edge steepness of -24 dB per octave. Each filter channel is equipped with its own audio input and output as well as a FM input. Thus, the A-105-4 can be easily used as part of polyphonic patches. Simply connect VCOs and envelopes with audio and FM inputs. Then, add a quad VCA (plus additional envelopes) after the filter module and voila, the polyphonic patch is ready to go. Input level, cutoff frequency, resonance and FM intensity are controlled by just one set of potentiometers to guarantee consistent results in all four voices. Additionally, there is a CV input with attenuator for each of the four parameters. High level settings result in distorted sound.
HE: | 3 |
TE: | 8 |
Depth: | 50 |
Power consumption +12V: | 70 |
Power consumption -12V: | 70 |
A-105-4 @Doepfer
WIth a long trajectory building synths, MIDI keyboards and designing bespoke devices for music pioneers Kraftwerk, Dieter Doepfer decided to design his own modular synthesizer in 1995 based on existing electrical and mechanical specifications of lab equipment he used during his years at university. The official presentation of the system at 1996 Frankfurt Musikmesse caught everyone by surprise and created lots of interest. After Doepfer published the specifications on his website, many instrument designers and engineers saw the potential of the new Eurorack format. Doepfer continues expanding their catalog of over 200 modules (and counting), operating from their modest offices in the outskirts of Munich.