User manual
mitted at a rate of nearly 2MHz unless you
patch an external clock signal to the adc clk
jack in Drezno. Jena’s processed data may be
delivered to its output synchronously with the
incoming clock period, or it can be re-sampled
with the internal (also very fast) clock. Ex-
ternal/internal clocking is selected using the
setup mode. Setting the internal clock may be
advantageous when your data is clocked slow-
ly at the source (e.g. Drezno) but you still want
to apply a quick modulation to the wave.
Regardless of the currently selected clock
source, processing in Jena occurs within
two distinctive regimes. With asynchronous
operation, every new input digital value is
translated almost instantly (there is a several
microsecond delay due to processing) to the
sample value of the current shape. This type
of operation is best suited for waveshaping
applications (e.g. folding and warping CV sig-
However, if you want to use Jena as an oscil-
lator you may prefer the input data to scan
the entire phase range of the waveform to
avoid the cycle being abruptly cut off before
edge of your ramp scans the waveshape and
may produce an audible glitch when not per-
fectly sharp. The synchronous regime does
not require the input data to scan the entire
range of 0…255 accurately and with a sharp
returning edge. Instead, it uses an algorithm
to analyze the incoming data and determine
its current frequency and phase. It then inter-
nally generates a perfect virtual ramp that
scans the function cycle in accordance with
the input cycles. This enables easy generation
of undistorted waveforms from the bank, like
in a classic wavetable oscillator, but with the
addition of through-zero phase modulation
from the phase jack. The disadvantage of the
synchronous operation is that there is a little
lag after each abrupt pitch change when the
new period length is computed. Also, modu-
lating the shape of the driving wave may con-
fuse the algorithm and cause pitch artifacts.
To select between external or internal clock
as well as to select between asynchronous
and synchronous regimes, press and hold the
encoder knob for a second. The display then
shows e or i
clock source, and a semi-graphical represen-
tation of the signal model (rising or falling
ramp) or off (indicating asynchronous op-
eration). Turn the encoder knob to cycle be-
5
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various input cv signals
transformed with the same
nonlinear shaping function
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Input CVInput CV
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Output CVOutput CV
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Input CVInput CV
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Output CVOutput CV
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Input CVInput CV
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Output CVOutput CV