“In the A-100, Doepfer have produced a capable and versatile analog modular synthesizer, built in the style of the classic modular systems of the seventies. The renaissance of analog synthesis in the last few years shows that analog sound production has a vital place alongside sampling and digital synthesis, and can produce sounds that are unobtainable by any other means. In addition to the unique sounds of its oscillators, filters, amplifiers, phasers, frequency shifters, and so on, analog synthesis can provide almost unbounded modulation opportunities, conventional and unconventional – limited only by the number and variety of modules available.
In designing the A-100, our priorities were: good sound quality; diversity of modules available; ease of integration into a MIDI system; and, maybe most important of all, affordability.
SSM 24dB Low Pass
“Module A-105 is another voltage-controlled low-pass filter with 24dB/octave slope. The A-105 is very similar to the A-122 that is made with a CEM chip. But in contrast to the A-122 the A-105 is made with the legendary SSM filter chip SSM2044. This chip was used e.g. in these synthesizers: 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 special feature of the 4 pole low pass SSM2044 is the patented so-called “true open loop design that delivers a characteristic fat sound not available from other devices” (extract from SSM2044 data sheet). The module will feature voltage controlled resonance and a sensitve audio input to obtain distortion – if desired. Regarding to the functions, controls and in/outputs the module is identical to the 24dB low pass filter A-122 that is built around a CEM chip. But the sound, the resonance behaviour and the distortion behaviour are completely different for both modules.”