The first stage is to set the reference drive current

1. Remove the jumper on JP100
2. Remove the jumper on JP101
3. Apply 0V to [1V/OCTAVE] (J102)
4. Monitor TP1 (or [SAW])
5. Adjust P201 for a frequency of 880Hz. This is not a critical adjustment, it simply allows multiple VCO’s to be set to the same ‘initial operating’ conditions

The next stage is to calibrate the Volt/Octave response of the module

1. Fit jumper JP101
2. Turn P102 fully anti-clockwise
3. Apply a voltage of 0.0V to [1V/Octave] (J102)
4. Adjust the frequency at TP1 )or [SAW]) to 110Hz using [COARSE] and [FINE]
5. Apply a voltage of 5.0V to [1V/Octave] (J102)
6. Adjust P102 one full turn clockwise and note the frequency reading.
7. Repeat steps (3) to (6) until the reading approaches 3600Hz
8. Apply a voltage of 0.0V to [1V/Octave] (J102)
9. Adjust the frequency at TP1 to 110Hz using [COARSE] and [FINE]
10. Apply a voltage of 5.0V to [1V/Octave] (J102)
11. Slightly adjust P102 clockwise and note the frequency reading.
12. Repeat steps (8) to (11) until a 5-octave transpose is achieved (110Hz and 3520Hz)

The last stage is to 'tune' the VCO so that it can be used with 1V/Octave controllers such as a MIDI-CV.

1. Fit jumper JP100
2. Set [FINE] and [COARSE] to their mid-position ‘0’
3. Apply a voltage of 0.0V to [1V/OCTAVE] (J102)
4. Adjust P101 for a frequency of 261Hz

An alternate procedure is to connect the CV output of, say, your MIDI Controller and play Middle C (C4, MIDI Note = 60). Set the [COARSE] and [FINE] pots to your preferred default position and then adjust P101 for an output of 261.63Hz

The remaining calibration process is for setting the wave shaper outputs:-

SAWTOOTH Output

1. Monitor the [SAWTOOTH] output
2. Set the [COARSE] and [FINE] controls so that the output is running at around 256Hz
3. Adjust P201 until the waveform is centred around 0V

TRIANGLE Output

1. Monitor the [TRIANGLE] output
2. Adjust P302 until the waveform is centred around 0V
3. Adjust P303 until the output is about 5V pk-pk
4. Adjust P301 for optimum waveshape
5. Adjust P303 until the output is about 5V pk-pk
6. Repeat steps (2) to (5) for best triangle wave shape

SINE Output

1. Monitor the [SINE] output
2. Adjust P306 until the output is about 5V pk-pk
3. Adjust P305 for optimum symmetry (peak shape matches trough shape)
4. Adjust P304 for optimum waveshape
5. Adjust P306 until the output is 5V pk-pk
6. Repeat steps (3) to (5) for best sine wave shape