A-100 analog modular Website
The module is no longer in production. The A-105 (or A-105-1, there is now the polyphonic A-105-4) is also reminiscent of famous models. An analog SSM2044 filter circuit is used here, which was already used in synthesizers such as the Korg Mono / Poly, the Fairlight II, PPG Wave 2.2 / 2.3 and last but … Read more
The Doepfer Diode Low Pass Filter is a lowpass filter with a slope of 24 dB. In terms of technical structure, it is similar to a so-called “ladder filter” (which works with a “ladder” or cascade of transistors), such as the Moog low-pass filter. Instead of transistors, however, diodes are used, which make the filter … Read more
The Opto FET filter uses optical field effect transistors. That’s a statement you have to let sink in first. Maybe meditate on it too, it certainly won’t do any harm. Until then, very quietly, the question arises as to what on earth an optical field effect transistor could be and why you need something like … Read more
After the Curtis chip CEM3320 was no longer available, Doepfer had to stop production of the A-123 24 dB highpass filter. It’s a pity, because there were simply no other 24 dB high-pass filters on the market! In the meantime, however, a replica is available with the AS3320, so that there is now a 24 … Read more
The module is no longer in production. Of all the modules that are no longer in production for one reason or another (most often it was the unavailability of certain Curtis chips, like the CEM3320 here), the A-123 filter was probably the most difficult to replace. There were simply no other 24dB high-pass filters, neither … Read more
The module is no longer in production. The A-127 BOM is an extension for the A-127 Triple Resonance Filter. It supplements the module with individual inputs for each of the three filters, as well as separate outputs (per filter) for bandpass, highpass, lowpass and notch. The original A-127, on the other hand, only offered a … Read more
The concept of the triple resonance filter A-127 reminds me personally of the resonators in the Korg PS3100, which make this polyphonic analogue dinosaur sound so special. Technically, however, the three integrated filters in the A-127 are more comparable to the SEM filter (even if they are preconfigured differently). In terms of sound, just one … Read more
The module is inspired by Friedrich Trautwein’s Trautonium, a forerunner of today’s synthesizer. The Trautonium became particularly well-known through the work of Oskar Sala, who used it to produce the film music for Hitchcock’s “The Birds”. However, other composers of the 20th century also composed for the trautonium, such as Paul Hindemith. In principle, the … Read more
A fixed filter bank is a “distant relative” of the graphic equalizer. We find 15 frequency bands whose volume is individually adjustable. Behind this are 15 parallel bandpass filters (with 1/2 octave bandwidth), whose output signals can be faded in. In contrast to a graphic equalizer, the fixed filter bank does not have a linear … Read more
The 18dB filter was created on the model of a well-known and popular small bass synthesizer: In principle, a transistor cascade is used here as in the 24 dB Moog filter, but only with three poles instead of four, and thus with a slightly lower edge steepness. The design may have come from a cost-related … Read more
