Additional calibration for the SVCO-B
TUN (main board):
This is the tune trimmer and it sets the range over which your VCO acts.
You are trying to set this so that the SVCO behaves in the same way as your other VCOs or
other musical instruments.
Set the frequency pot to the middle position, which is indicated by a small line on the
suggested front panel. Using the INC/DEC switch ensure that the module is set to the 8'
octave. Adjust TUN so that the SVCO produces the same pitch note as your other VCOs. The
range of the TUN trimmer is around three octaves so it should be wide enough to cope with a
variety of requirements.
As far as I am aware there is no standard amongst modular systems that defines what pitch
corresponds to what CV input. However, I choose to make my VCOs produce middle C (C4)
at their typical settings when the 1V/octave input is at 5.00V. Thus, I would expect the
SVCO-B to be producing 261.6Hz when its KeyCV input is 5V, the frequency pot set to 12
o'clock and the octave in the 8' position.
Synthesizer.com do things a little differently. Indeed, if you were to use an Oakley/MOTM
build of the SVCO you would find your SVCO would operate some four octaves lower than
your other Dotcom VCOs. The parts lists provides a Dotcom option on two of the resistor
values to allow for this.
With Dotcom build of the SVCO-B you need to adjust the TUN trimmer so your SVCO-B
produces a C of 130.8Hz with the octave setting at 8', the tune pot at 12 o'clock and no
KeyCV input at all.
OCT (main board):
This sets the sensitivity of the SVCO main board to the octave board's
CV output. Use the INC/DEC switch to put the module into 8” and set the frequency pot to
the middle position if it's not already. Play an A on your keyboard and using the front panel
frequency pot set the frequency to be exactly 220.0Hz. Now flip the INC/DEC switch so that
the module is now in 2”. Adjust OCT so that the note heard is 880Hz +/- 1 cent. Check that
selecting the 4” octave produces 440Hz.
OCT2 (octave board):
Reset the SVCO to 8”. Now play a note on your keyboard that gives
you a 880Hz output, it should be another A but two octaves higher. Using the DEC switch
take the module down to 32”. Now adjust OCT2 so that you get 220Hz +/- 1 cent. Check that
16” produces 440Hz.
Be aware that changing OCT on the main board affects all octave settings except 8”. While
OCT2 only changes 16” and 32”. OCT should therefore always be calibrated before OCT2.
LOF (octave board):
This sets the operating frequency of the SVCO-B when it is in LFO
mode. Ensure that the LO LED is lit and you have no external CV inputs patched in or via the
Oakley Buss. Now turn up the frequency control to its maximum setting. Now adjust LOF
until the SVCO is producing a signal of around 450Hz to 550Hz.
Now you have set up your SVCO-B and you are ready to go.
10