Mini VCO 103 Build Guide

Assembly Instructions

The Mini VCO 103 module has no particular build requirements not already covered in the ‘General Build Info' page.

Calibration

1. Power up module and allow to ‘warm up’ for 15 minutes
2. Measure mV across TP1 pins and adjust Pr5 ‘Null’ until as close to 0mV as possible
3. Put the supplied red jumper on JP1. Adjust Pr1 ‘Set C5 with JP1’ until pulse output frequency is 523.25Hz. Then remove the red jumper, it is no longer required.
4. Set coarse pot fully CCW, Fine pot fully CW
5. Apply an accurate CV of 5V to the V/Oct input. Adjust Pr2 ‘Set C5 @ 5V CV’ until pulse output is 523.25Hz
6. Reduce the CV from 5V to 0V. Adjust Pr4 ‘Scale’ until pulse output is 16.35Hz.
7. Increase CV from 0V to 8V and adjust Pr3 ‘HF Trim’ until pulse output is 4186Hz
8. That completes the calibration. The V/Octave tracking should be excellent from 16.35Hz through to 4186Hz and beyond subject to accurate CV calibration voltages and accurate frequency measurement. Aim for better than 0.05% accuracy from your test equipment for best results.

PCB Parts List

 *See below for MOTM or MU Potentiometers

 Module Parts List

PCB Layout