A-100 analog modular Website
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
The Vactrol filter has several special features. Most striking: There is a separate input for each of the operating modes lowpass, bandpass and highpass. This allows several very different sound sources to be treated differently in a single filter. Only the cutoff-frequency and the resonance (and resonance control) are common. If that’s too much for … Read more
Like the A-120, the A-108 filter is also based on the Moog transistor cascade, but uses not only 4 poles, but 8 and can therefore have a maximum slope of 48 dB. That sounds sensational at first, but in real synthesizer life it’s not that extremely spectacular. What is striking, however, is the fantastic and … Read more
The Wasp Filter uses the somewhat idiosyncratic filter circuitry of the 1978 EDP Wasp synthesizer. The 12 dB filter produces very peculiar, “wild” distortions at higher resonances, which, however, always remain very easy to control. Possibilities and structure of the module (but not the layout of the front panel) are similar to the A-106-5 SEM … Read more
