The Wrangler is all about interfacing between video modules and non-video modules. Video modules tend to work with voltages mostly in the 0V to 1V range, whereas non-video modules often use a much wider range of voltages, including negative voltages below 0V. The eurorack power supply rails are -12V and +12V, which sets the theoretical maximum range of voltages your modules might need to deal with. The controls on the Wrangler let you scale and offset the input voltage, and the front panel LEDs give an immediate indication of the results of that conversion.
When converting from +/-12V CVs for video use, the most important LED is the main (usually green) 0-1V LED in the middle of the meter – if it’s the only one lit then the output CV is safely in the video range. If the 0V LED on the left lights up then the signal contains voltages that are too low and may be ignored by video modules (i.e. interpreted as 0V, meaning “black” or “no modulation” etc.) Similarly, the +1V LED on the right lights up when the output voltage is too high for video modules and signal detail might be being lost. By watching these three LEDs and wiggling the offset and scale knobs any CV can be adjusted to make sure it falls within the useful range for video.
In the other direction, when processing video CVs for use with audio eurorack modules, the Wrangler can be used to scale the voltages up to the wider voltage range required, and optionally shift the signal to generate a bi-polar signal that is both position and negative. The -5V and +5V LEDs light up when the output voltages are below -5V and above +5V respectively, indicating that the output CV is spanning a more conventional eurorack voltage range.
My two favourite uses for the Wrangler is to boost a horizontal or vertical sync pulse up to a voltage that’s high enough to sync a non-video oscillator, and to convert an non-video oscillator’s wide range bipolar output into a 0-1V video signal.
The clipped output of the Wrangler guarantees an output voltage that will never be less than 0V, or greater than +1V. This can be useful when interfacing with modules that aren’t tolerant of wide voltage inputs, but can also be interesting as a waveform clipping or distortion effect, sharpening the corners of smooth input waveforms.
The Wrangler PCB includes two jumper options on the PCB: one to set whether the second input is inverting or non-inverting, and the other to enable or disable the clipping on the second output.
If you’d like to read more about video signal levels and why 0-1V is the more common “standard” for eurorack video modules then have a look at this 2010 forum thread for some historical perspective.
The word “wrangler” is derived from the German “wrangeln” meaning “to dispute” or “to wrestle” and is these days often used to describe “a person in charge of organising horses and other livestock on a ranch”, which is kinda what this module does – wrangling signals into the right voltage range! 🙂