Thread: Filters as noise sources
Addendum: After a couple searches online, I can't find any hardware Eurorack modules that have an absolute value function. That seems weird―software modulars always have it.
As a substitute, you can square the feedback signal with a four-quadrant multiplier, but this is less effective. The square function further attenuates quiet signals (making the chaotic behaviour harder to initiate), and further amplifies loud ones (which tends to peg the filter to +10 volts) so the range of filter parameters that will produce noise becomes very narrow.