Stereo Cascaded OTA VCF

Stereo analog filter with internal frequency cross modulation & multi outputs


There are 2 independent but identical analog filters that are controlled as stereo from stereo frequency - stereo resonance - stereo CV and stereo V\O.
Each filter has 2 different inputs with level control, one input for high pass and band pass and the other input for 2 different low pass .
There are 2 outputs at each filter , the one that appears as HP+LP gives 2 pole high pass and 1 pole low pass and the other out that appears as BP+LP gives 4 pole band pass and 3 pole low pass .
Because of this special feature of different inputs and outputs you can use each filter as a voltage control cross fader too.
Another feature is that when the filters reach the self oscillation they can generate a sine-triangle wave with 4 octaves good volt per octave tracking! And the frequency can go low enough too to become an LFO!
Last as the RF DPVCO the RF SCOTA VCF has internal cross modulation for FM of each other, so here the madness begins...!
About the inputs there is internally normaled connected both inputs of Alpha filter into Beta filter for making stereo instantly any source .
Also because the potentiometer levels of low pass inputs can be driven and saturate or overdrive , for a clean sound don't push them over 50-60 %.
About tuning the core filters for stereo use you must get the frequency knobs of Alpha and Beta at the middle and the Stereo frequency at the middle too, then get the resonances of both filters and the stereo resonance fully clockwise to self oscillate, then tune them at the same note precisely by tweaking a bit the beta or alpha frequency knob, and that's it! you can get your resonances at the middle or less for not oscillation and use the filter as stereo by tweaking only the stereo knobs.
Another important thing to mention is that the stereo frequency and stereo resonance knobs work as offset for both filters Alpha and Beta.
For volt per octave control voltage there are 3 cv inputs : one it is the stereo v/o and two v/o for Alpha and Beta filters separately .
There will be more info soon but if you are interested you can contact me for further details ;)

  • 60 mA +12V
  • 60 mA -12V
  • 0 mA 5V
  • 50 mm deep
  • Ø 5.00 (1 Votes) Average Rating

This Module is currently available.

$292 Price in € submitted Feb 7th 2020, 00:35 by radicalfrequencies | last Change Mar 4th 2020, 19:52 by radicalfrequencies

5 Users are observing this