Erica Synths SUPER-SYNCABLE VCO, Руководство по сборке

Страница: 8 / 9

CALIBRATION
Ensure all components are placed correctly and soldered well. Check
for possible short circuits that may be left after soldering.
Ensure power supply voltages are as e12.00V and -12.00V as
possible.
Allow some minutes for the VCO to warm up.
Connect a precise voltmeter with range at least +/-15V to the Test Point
1 (TP1).
Set panel FREQUENCY pot to 12 ‘o’clock. When tuning VCO2, set
DETUNE pot to 12 ‘o’clock. Set CV level pots to zero.
Switch around various octave settings. Check the voltage change on
the voltmeter between octaves. Ideally it should be 1.00V per octave.
Tune tirm pot VR1 so that octave steps are as close to 1.00V as possible.
Mostly you can just switch between two center settings, and adjust the
trim pot, only occasionally checking voltages on other settings.
If voltage change step between octave switch steps is wider than
necessary (more than 1.00V), turn the trim pot clockwise. If voltage
change step between octave switch steps is narrower than necessary
(less than 1.00V), turn the trim pot counterclockwise.
If 1.00V steps can only be acquired on certain octave switch settings,
mismatch in octave divder resistor array.
After successful tuning, voltages on the output of octave selector should
be like, for example, -9.62V at -3 (or lowest octave setting), -8.62V at
-2, -7.62V at -1, -6.62V at 0, -5.62V at +1, -4,62V at +2, -3,62V at +3 (or
oscillators, what is important, is the exact 1.00V relation between steps.
Select SAW waveform.
Ensure panel FREQUENCY pot is 12 ‘o’clock, and both modulation pots
are set to zero. When tuning VCO2, set DETUNE pot to 12 ‘o’clock.
Set the octave switch to some middle-low setting, -1 oct for example.
Connect a precise frequency meter or even better – a chromatic tuner
to the VCO module output.
Connect CV keyboard or midi keyboard through midi-CV converter.
Play C4.
standard it is in the middle position.
Note the frequency on the frequency meter of tuner. Play around
several octaves. Check the ratio of frequency relative to the previous
one. Ideally it should change twofold for every octave when going
higher, and should half per every octave step when going lower.
For example: Say, you have written down the frequency X Hz at the
setting C4 (or the tuner shows C4), when playing C5 output frequency
should read 2*X (or tuner show C5).
Tune trim pot VR3 so that octave steps in measured frequency are as
close to the shown above as possible. Mostly you can just play between
two octaves and adjust the VR3, only occasionally checking frequencies
on other octaves.
Turning the trim pot VR3 clockwise with make octave steps narrower,
while turning counterclockwise - wider. Overall tuning will also change
at the same time - this is not a malfunction. So, if the octave frequency
step is too wide, turn the TP3 clockwise a bit, and check the octave step
again. If it is too narrow, turn the TP3 counterclockwise.
---
When you are happy with tuning, play C4 on the keyboard, and check
frequencies on frequency meter or chromatic tuner, when switching
octave switch. You may need to adjust VR1 to get ideal tune, when
changing octaves by octave switch.
---