HP VCF 111 Build Guide

Assembly Instructions

The HP VCF 111 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 10 minutes
2. Connect a 440Hz sine wave @ 10V Pk-Pk to Signal input 1. Resonance to 0%, Cut-off to 0%, Signal 1 Level to 100%.
3. Adjust Pr1 to give a 10V Pk-Pk output using an oscilloscope
4. Remove the sine wave signal from input 1. Set resonance to 100%. Connect a frequency meter to the output.
5. Adjust Cut-off to give 100Hz
6. Apply a CV of 4V to the COF CV in 1 input
7. Use Pr2 to calibrate at 1.6kHz (see note below)
8. Repeat from step 5 until 4V gives 1.6kHz

Note: If the frequency is flat (<1.6kHz), use Pr2 and make the frequency lower (flatter), if above target frequency, use the trimmer to make the frequency even higher, this can be counter-intuitive. You will soon get the feel of how much to increase or decrease the frequency by

PCB Parts List

*See below for MOTM or MU Potentiometers

Module Parts List 

PCB Layout