Soviet topology 4-pole morphing low-pass filter
During the 1980's, a Russian electronics designer realised that one could build a musical filter using a fairly unconventional method. Unlike most other filter topologies, this method did not use capacitors to employ an RC time constant in its core filter stages. Instead, the internal properties of a programmable amplifier chip are modulated by a special "programming" input found on these devices. One of the modified properties is bandwidth of the amplifier. Changing this particular attribute over time effectively limits the frequencies that can pass through the amplifier, resulting in filtering! Because attributes other than bandwidth are also changing at the same time, this filter stage has instabilities at certain frequencies along the audible spectrum, resulting in colourful distortions and a character all of its own. The resonance's character is especially profound, resulting in bubbly and sometimes screeching sci-fi tones. The Red Dragon achieves a 24dB/oct resonant low-pass response by cascading four of these stages. What's more, you can morph between the two pole extremes (6dB and 24dB) to change the slope of the filter on the fly, either manually or through voltage control.
Rich 4-pole filtering with a control set made just for modular synthesizers
This Module is currently available.$249 submitted Sep 7th 2016, 15:48 by hexinverterdotnet | last Change Nov 23rd 2016, 23:26 by hexinverterdotnet