
Circuit Slices, LLC Dual Parallel VCO User Manual CS023
Calibration
The two VCOs are on separate PCBs that plug into 26-pin header sockets. Each board has three
ulti-turn tri ers. P1 is adjusted for a 1-volt-per-octave pitch response. P2 is used for high-
frequency tracking, if needed. Finally, P3 is used to adjust the shape of the sawtooth output.
This odule ships factory calibrated. If it beco es necessary to adjust one or both oscillators, a
frequency counter and oscilloscope will be needed. Adjust P1 for a one octave shift fro 100Hz
to 200Hz for a 1 volt control voltage change. Then adjust the FREQ control to 2000Hz and ake
an increase in the CV by 1 volt for a change to 4000Hz. Adjust P2 if necessary. After the high
frequency tracking adjust ent, you ay need to re-adjust P1. You ay have to co pro ise a
little to get it tuned over the entire range. The oscillator pitch ay beco e “sharp” as you go
above the usically useful range (8 kHz) but will still respond, increasing up to and above the
hearing range. Adjust P3 so that the sawtooth output displays a s ooth ra p on your
oscilloscope.
The FINE controls were designed to give the ost range and still retain enough sensitivity to
tune an interval between the two VCOs. So, you ay find the FINE controls a little ore
‘course’ than you would expect, but still pretty easy to adjust.
Output I pedance
Each output includes a series 1K oh resistor, like classic VCO designs. While not really
necessary for output protection with today’s op-a ps, the resistors ake it possible to
passively add two signals together using “stackable” cables or a passive “ ultiple”. This eans
you can patch two outputs into a single VCF or VCA input, without needing to use a ixer. Try
co bining different wavefor s for interesting ti bers.
This odule is warranted for one year with parts, under nor al use – not including the
application of reverse or over-voltage power by custo er. Return shipping to Circuit Slices
fro custo er not included. Return to Circuit Slices, LLC for repairs. Circuit Slices, LLC reserves
the right to replace the odule if necessary. Please keep your receipt / packing slip for
warranty infor ation.
Circuit Slices, LLC
10028 Windja er Trail
Aurora, OH 44202