CALIBRATION
1) Connect the VCO to the PSU. Let it "heat up" for ~10mins.
2) Turn the VCA Envelope potentiometer all way CW, TUNE potentiometer to 12:00 and all other
potentiometers all way CCW! Set waveform select switch to the SAW, VCF mode switch - to LP!
Install the VCF configuration jumper to Attenuator position (lowest).
3) Connect the main output to a chromatic tuner, and then to the mixer with headphones or monitor
speakers.
4) Rotate the Cutoff knob and you should hear VCF opening and closing. Adjust the trimpot R140 so
that the VCF closes completely at full CCW setting of the Cutoff knob.
5)
Now it’s time to tune the VCO! The VCO SCALE
trimpot is accessible thru a small hole on the front
panel. Connect ka keyboard/midi-CV interface that generates 1V/oct CV to the 1V/oct input!
6) Play C4 on the keyboard and use TUNE potentiometer on the front panel to adjust tuning so that
tuner shows C4!
7) Play C5 on the keyboard and see the tuner reading!
8) If the tuner shows something higher that C5 use SCALE tripmot to INCREASE the frequency of the
VCO slightly. If the tuner shows something lower than C5, use SCALE trimpot to DECREASE
frequency slightly!
9) Play C4 again and use TUNE potentiometer to adjust tuning so tuner shows C4 again.
10) Play C5 and see, what you get. The tuning should be more precise. If it’s not exactly C5, go back to
the step 6!
11) Once you are happy with C5, check what you get on C6, C7 and C3. You may need to adjust it little
bit more as described on step 6.
12) The trimpot R24 is for high frequency scale adjustment, but in most of the cases you just leave it in
the mid setting.
NB! In some cases you may experience malfunctioning of the suboscillator at low frequency settings
of the principal oscillator. The reason is that the pulse wave has distinct peak on the rising edge and
the suboscillator is triggered twice, so it generates the same frequency as the principal oscillator.
There are two ways, to solve this:
1) Replace C42 and C45 by 47nF; R96 and R110 by 20k, or
2) Cut a trace that leads from C43 and C44 to the OSCSQR (TP6) and use a wire to connect the C43
and C44 to the OSCSAW (TP5) as shown in the picture below. You may also desolder bottom pins of
C43 and C44, connect them above the PCB and use a wire to connect to the TP5.
If you succeeded with calibration
–
congratulations
–
you have completed the most advanced module
of Erica Synths DIY line! Enjoy!
If you have any questions about the construction and troubleshooting, please refer to
All our DIY kits are numbered and photos of kits are registered on closed Facebook group, so in case
some parts are missing form kits, please, send an email to
and we’ll take care of
every issue.
We do not provide warrantee on DIY kits, as we can’t take responsibility on built quality, but we provide
repair services, and cost is 25EUR/hour.
GUIDE TO ASSEMBLY OF ERICA SYNTHS BASSLINE
cut
connect
