1V/Oct calibration procedure:
The Corgasmatron is capable of being tuned to track 1V/Oct over a range of about
three to four octaves. You can tune the tracking using the dedicated 1V/Oct trimmers on
the back of the pcb. The calibration can be done by ear or using a frequency meter.
All you need is a voltage source capable of playing octave intervals (e.g. midi keyboard
+ cv converter).
Filter A:
1. Turn Q to max, Q Drive to zero and then adjust Freq to the base note you would like
to use (i.e the lowest note you plan to play).
2. Plug your CV source capable of playing 1 Octave intervals (i.e. 1V increments) into
the left "1V/Oct" jack.
3. Plug your frequency meter into Out A or use headphones/speakers to listen to the
output if tuning by ear.
4. Make note of your base frequency and then using your CV source increase it by one
octave. If the new octave is sharp relative to the base note then adjust the trim pot to
make the note
sharper
(note this may be counterintuitive). If the new octave is flat
relative to the base note then adjust the trim pot to make the new note
flatter
.
5. Repeat step 4, alternating between two intervals until it sounds in tune (or the
frequency meter is showing a close to perfect doubling of the frequency between the
base note and the first interval).
Filter B:
Follow the same procedure but monitor Out B instead.
NOTE: make sure the SERIES/PARALLEL switch is set to "PARALLEL" so that none of
Filter A is influencing the tuning.
Corgasmatron Manual v1.0
Page 6 of 10
