
Design notes
Full-wave rectification (FWR) transforms a bipolar AC signal so that the negative amplitude portions of the
signal become positive. It does cool and interesting things to harmonics. For example, a FWR sine
waveform loses its fundamental and has a new fundamental at twice the frequency. This forms the basis for
the module: 1 is the dry signal. 2 FWRs the incoming signal. 4 FWRs the signal resulting from 2, and so
on.
Most modules in the NE lineup start as one of our conceptions and we champion it. This one was one of
Stephen’s. He has been interested in full-wave rectification distortions for a long time: he built his first one
in high school! It was only a matter of time before he convinced the rest of team NE that we needed to make
one in Eurorack.
Pura Ruina started as a simple full-wave rectification module long before we dreamed up the Distortion-of-
the-Month series. We initially conceived of it as more of a simple 4hp “anti-filter” that would do really cool
things. Then we prototyped it and it did not do really cool things. It did not even do vaguely cool things.
We tweaked and tweaked and at least Stephen remained convinced that there was a kernal of...something
there. The rest of us were skeptical but believe it might have merit. We sat on it for a few months.
And then there was the fateful day when we decided to do a series of distortions. Although the concept for
the series was based on other circuits and modules, Pura Ruina quickly slotted in. We revised it to fit that
line.
The first go with this revision blew us away. A simple sine wave in with a bit of modulation sounded almost
like polyphony. He was vindicated! The idea had been good after all!
The sonic possibilities PR opens up are way beyond what we hoped for with this one. Where our other
distortions can do pretty EQ, crazy drive, hella resonance...this one is a beast entirely of its own.
The first version remained 4hp. It full-wave rectified, but didn’t stage split, and wasn’t CV-able. It was
better than the previous incarnation, but Stephen pretty quickly spotted the potential this time around and
slapped the circuit together.
4