SAlut
Thank you for purchasing this Xaoc De-
vices product. Sofia is a fully analog volt-
age-controlled oscillator (VCO) based
on an original waveforming principle.
It features a modern, well-calibrated,
temperature compensated triangle core
and two elaborate waveshaping and
modulating sections. The sound is a mix-
ture of a warm, saturated base tone and
two ripple components. Besides its main
output, Sofia offers access to individual
components of the sound plus a multi-
tude of modulation inputs allowing for
extensive self-patching and animation
of the waveform. To better understand
the device, we strongly advise the user to
read through the entire manual before
using the module.
InStAllAtIOn
The module requires 24hp worth of free
space in the Eurorack cabinet. Always
turn the power off before plugging the
module into the bus board using the sup-
plied ribbon cable. Pay close attention to
power cable pinout and orientation. The
red stripe indicates the negative rail and
should match the dot or –12V mark on
the bus board as well as the unit. Sofia
is internally secured against reversed
power connection; however, rotating
the whole 16-pin header
may cause se-
rious damage
to other components of
your system, because it will short circuit
the +12V and +5V power lines. Always
pay close attention to the proper orien-
tation of your ribbon cable on both sides!
The unit should be fastened by mounting
the supplied screws before powering up.
OPerAtInG PrIncIPle
Sofia implements and extends the classic
computer music method for synthesis
of formant sounds called FOF (fonction
d'onde formantique), which uses a com-
bination of simple, time-domain com-
ponents (decaying sinusoidal waves) to
achieve desired spectral characteristics
(see infobox, page 7).
In Sofia, two of such ripple elements are
added on top of a slightly saturated sinu-
soidal base tone. Each new cycle of the
2
module
explained
0 0.005 0.01 0.015 0.02
Time (s)
fig. 1: example waveforms
