This is a rungler module in Kosmo format.
Rob Hordijk developed the rungler, including it in his well known Benjolin synth. (He also designed a synth module called Rungler, but it is somewhat more elaborate than the Benjolin rungler used as the basis for this module.) It is a control voltage sequence generator based around a digital shift register, somewhat resembling the well known Turing Machine module. Unlike the Turing machine, the rungler is deterministic, not random, though it is unpredictable enough to render the distinction somewhat moot.
It takes two inputs: A clock to advance the sequencer to the next step, and an input signal which governs when new bits are injected into the shift register. The clock is normally a periodic gate or trigger, but either signal can be periodic or not, and can be binary (gate, trigger, or pulse/square wave) or otherwise (ramp, triangle, sine, whatever). As long as the clock signal goes above and below a threshold of about 1.2 volts it will cycle the rungler. The input will affect the sequence as long as it goes above and below a threshold that can be anywhere in the range -9 V to +9 V, set by a knob on the front panel. The threshold knob does nothing very useful if the input is binary, but can have an effect when using non binary input signals.
Also on the front panel are:
- A feedback switch. This enables or disables sending the output of the last stage of the shift register to be XORed with the input to determine the next bit to be loaded in. Feedback on is the “normal” configuration, hard wired in the Benjolin, but you may find it useful to turn it off sometimes.
- A loop offset switch and knob, as introduced (I think) by Tseng Kweiwen. When the switch is turned on, the knob controls a DC voltage level to be mixed with the input. When fully counterclockwise or clockwise this DC level dominates, so the input does not affect the shift register and the result is a repeating loop of length 8 or 16 clock pulses, respectively. (Feedback must be turned on for this to work.) When centered, the rungler operates in its normal mode with the inputs XORed with the fed back signal. Somewhere above the center position it switches to a mode where the output is simpler and more repetitive, but does change now and then. Somewhere below the center position the output becomes a DC level.
The input threshold knob and the feedback switch are modifications not typically seen in Benjolin or rungler builds.
There are two copies of the output sequence available on front panel jacks. Two more jacks provide GATE, the state of the last stage of the shift register, and the XOR of the input and GATE (as 0 and ~5 V levels). Indicator LEDs show the state of the clock, input, GATE, and XOR.
