9 1V/Oct INPUT :
This is a frequency cutoff modulation input with a fixed control level corresponding to
one volt per octave. It can be useful to patch a pitch cv to this input so that the filter
automatically “opens” at this rate as the pitch gets higher. This input can be used simulta-
neously with the other frequency control inputs FCV and D-FCV.
Also, when the filter is in SELF OSCILLATION mode then applying a pitch control voltage
to this input allows the filter to be used as a Sine wave VCO with reasonably accurate
tracking over a four octave range, however do note that there is no temperature compen-
sation on this, so it is calibrated to only track well at regular room temperature (21
degrees C)
10 VCF FCV Input :
This is the main frequency control input for the filter, and voltages or signals patched to
this input control the cutoff of the filter at a level (and inversion) set by the Freq CV Level
control.
The FCV input can be a fixed voltage or a waveform, either at low frequency from an LFO
or similar for modulation or at audio rates from a VCO.
The accepted signal range is -5V to +5V. Any voltages higher or lower than this will be
capped to +5 or -5V. Maximum permissible voltage to this input is +/-12V.
13 BP Output :
This is the Band pass output, the slope is 6db per Octave.
11 VCF Input :
This is the audio input to the filter, and it is routed to the Input level control (6).
In no input is patched to VCF 2 Input (IN 2) then it is normalised to Input 1 if the
Dual/Cascade switch is set to DUAL, and it is normalised to the OUPUT of VCF1 Mode
switch if the Dual/Cascade switch is set to CASCADE. Plugging a patch cable into IN 2 will
defeat this normalising and the external signal patched in then takes priority.
Please note: This filter (like many vintage synth filters) is intended for processing audio signals
only as it is AC coupled - so is therefore it is not suitable for processing control voltages
through the audio input. It won’t cause a problem, the input capacitor simply blocks any DC
voltages.
12 LP Output :
This is the Low Pass output, the cutoff slope is 12db per Octave.
14 HP Output :
This is the High Pass output, the cutoff slope is 12db per Octave.
Description of individual filter controls (cont.)
VCF1 and VCF 2 are identical and independent, these labels apply to both.
