The Iron Ether Pithoprakta is a 16HP module for the Eurorack synthesizer format, which generates new rhythms in real time, based on a combination of randomness, looping, and evolution over time. Nearly all parameters can be controlled by external control voltages or gates.
At its core, Pithoprakta has 8 channels of random trigger or gate generation, all clocked by a common clock input. The probability values for channels 1 and 8 can be defined directly, with the Prob 1 and Prob 8 knobs, respectively, as well as their associated CV inputs, each with its own attenuator. The values of channels 2 through 7 are interpolated between these, allowing the user to create a spread of probabilities, and modulate the density levels in complex ways with only one or two external modulation sources.
When looping is engaged, the Prob 1 and Prob 8 knobs and CV inputs change from setting the probability of the outputs being on or off, to now setting the probability that a given step of the loop will be over-written on the next step. In other words, they become "probability of change" controls. Low settings will repeat the loop with small changes over time, eventually becoming something entirely different.
Pithoprakta also includes a bonus CV output, derived directly from the states of the gate outputs. This CV sequence will loop and evolve along with the gate outputs - useful for things like pitch sequences and random modulation of filter cutoff.
When the Div toggle switch is set to the right, Divider mode is engaged. Each output is now clocked by a different division and/or offset of the input clock. From left to right, the columns of outputs are divided-by-two, divided-by-four, divided-by-eight, and divided-by-sixteen. The upper four channels receive odd-numbered clocks, while the lower outputs receive even-numbered clocks. Musically, these correspond to downbeats and upbeats, respectively.
"Pithoprakta" is a Greek word coined by avant-garde composer Iannis Xenakis, to mean "actions through probability."
CV Out jack sends stairstep-type random looping CV sequences, based on the states of the 8 Gate Outputs
Trig/Gate switch sets outputs to send either gates or triggers - trigger and gate lengths can be set using the System Mode
Div Switch engages Divider mode
Reset pushbutton resets Loop and/or Divider count
Loop illuminated pushbutton engages looping and displays loop status
Current draw: +12V: 25mA, -12V: 1mA (using 5V power, 5V: 25mA, -12V: 1mA)
Metal shaft potentiometers, 100,000 cycle life, bolted to panel
Jumper selection for internal/external 5v power
Reverse polarity power protection, full over/under voltage protection on all CV/gate inputs
Header for the 8 outputs allows for future expander connection or your own DIY expanders
Binary inputs trigger at a threshold level of ~1.5V and are conditioned to trigger reliably even from non-pulse waveforms
Binary outputs are 0V when low and 5V when high
CV inputs are natively 0V to 5V; built-in attenuators and offsets allow any normal modulation signal to be accepted
CV output is in the range 0V-5V
Clock input accepts clocks up to 1kHz, or 1000 cycles per second for audio rate pitched noise and random wavetable oscillator purposes
Includes 16-page printed manual, four M3x6 mounting screws, 16-to-16-pin power cable