Doctor Octature can be used in two different ways. On the one hand it is a octature-LFO which means it´s a sinewave LFO with eight outputs, shifted 45° in phase to each other. On the other hand it is a lowpass filter with eight outputs. It´s design is similar to the analog filters from Roland.
The basis of the module is a 4-pole LPF inspired by the classic “cascaded OTA” design, but realized instead with superior-quality 2164 VCAs. The cascaded OTA design was used eg. in the Jupiter-6 and the SH-101.
If the filter is in self-oscillation you can output eight sine waves which are each 45° apart in phase.The filter can track 1V/oct and thus you get a “octature VCO/LFO”. Used as a filter the eight outputs are pairs of 6dB-, 12dB, 18dB und 24dB-low pass filters. If you mix different filter outputs new filter types can be created!
Coarse and Fine tuning
Range switch for LFO (0.002Hz to 300Hz) and VCO (17Hz to 24kHz) modes
VC Resonance with logarithmic response for smooth control
1V/Oct temperature stable tracking
Mono/Quad resonance gain distribution switch for classic or enhanced performance
Monopolar FM1 and Bipolar FM2 attenuated CV inputs
Single pcb design (very shallow/skiff friendly)