Oakley VCO 5U - Manual (Page 7)

SCL2 – This trimmer sets the scale of the KCV2 output
Repeat the above but with your second VCO and use the Key-CV2 output.
The purpose of both SCL trimmers is to ensure that the VCO Controller adds nothing to the
CV signal when the two depth pots are at their minimum settings and the switches are in their
middle positions.
+OCT – This trimmer determines the note played when any octave switch is set to +1.
Play a note somewhere in the middle of the keyboard, say a low A at 440Hz. It should be in
tune. Now flick the top switch to +1 and the VCO that is connected to KCV1 should go up in
pitch. Adjust +OCT so that the pitch is exactly one octave higher than it was when the switch
was in its middle position. Flick it back and forth a few times to make sure the interval is
exactly an octave.
-OCT – This trimmer determines the note played when any octave switch is set to -1.
Play the same note on the keyboard. Now flick the top switch to -1 and the VCO that is
connected to KCV1 should go down in pitch by about an octave. Adjust -OCT so that it is
exactly an octave lower.
Ensure that the KCV2 output is similarly affected. There should be no appreciable difference
in octave intervals between KCV1 and KCV2.
Note that tweaking +OCT will affect the -1 octave setting as well as the +1. If you tweak the
+OCT trimmer for some reason, you will have to re-tweak the -OCT one as well.
OFFSET – This trimmer adjusts the control breakthrough of the internal VCA.
Plug an unconnected patch lead into VCA IN and let the other end hang so that it doesn't
touch anything. Now connect your amp or mixer to the VCA OUT socket (not the VCA CV
OUT) so you will be able to hear what is the VCA is doing. Keep the volume down low for
the moment. Connect the SQR OUT of the module into the VCA CV IN. And turn up the
volume slowly. You should be able to hear a thumping in time with the modules LFO. Turn
the rate up a bit if its going too slow.
Now adjust the OFFSET trimmer until the thumping is minimised. You may have to turn your
amp up a bit to make sure the last remnants are reduced to their lowest settings.
Now unplug everything. It's time to create the a nice sine wave. If you have a oscilloscope
then this will be easier but if not do not fret.
Using the 'scope adjust the two trimmers, SHAPE and SYM, until you get the best shape sine
wave from the SINE OUT socket.
If you haven't got a 'scope, you can use your ears. Turn the LFO RATE pot all the way up.
Listen to the sine wave output. You will hear a deep bass tone. Adjust the SHAPE and SYM
pots until you get the dullest sound with minimal overtones.
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