DWS: Diode wave-shaper (14HP)
5 in stock.
DWS, also known as the 'Diodular Wave Strangler' - an object lesson in what sort of generally weird things you can down with a bunch of diodes and an op-amp. The circuit is based on a public domain schematic that I ran across whilst idly browsing and I figured it might be fun to see what it sounded like.
The circuit is pretty simple - it consists of 8 diode 'stages' which rectify the incoming signal and then mix and amplify the results with the 'main' signal. It's a very interesting effect and is a bit like the Lockhart wavefolder on crack.
The exact output is very much dependent on what you put in, and even small changes can result in some entertaining effects. The controls can be a bit on the twitchy side (again, depending on other settings and the nature of the input) but the results are, I think, well worth it.
If you want instant gratification, this module probably isn't for you (wait for the slimmed-down, 4-stage version which offers a bit more immediacy) but if you like fiddling and dig weird timbres, this might be right up your street - whilst it can be used in more 'dynamic' pieces, I feel it is particularly suited to drones and the like.
It's important to note that you're likely to get more discernable results from stages 5-8 if you've got a strong input signal - each diode stage will knock around 0.3V off the input due the effect of the Schottky diodes (0.6V if you built it with 1N4148s or similar), so for a 5V input, by the time the signal reaches stage 8 it has been reduced to around 3V - you may be able to recover some of the voltage loss through use of the output gain (that's what it's there for!)
You won't find any voltage control here - this one is very much for the knob twiddlers; there are 'shape' and 'slope' pots (this is what was on the schematic - I'm still trying to work out where they fit into the grand scheme of things) plus control pots for the voltage dividers on each of the diode stages. Finally, there's an output gain pot to give the shaped signal a bit more presence. On top of that, there's an input and an output.
You'll get best results from sine or triangle-based waveforms - square waves are affected very little (or at all) and sawtooths are somewhere in between. You won't have much luck processing audio-level signals unless you amplify them (a lot) - this module is designed for modular-level waveforms.
Whilst this module isn't particularly deep (around 20mm) it is wide at 14HP. That being said, since the only active component on board is a quad op-amp(!) the power consumption is actually pretty low (figure on around 30mA, tops)
THIS IS A PCB/PANEL SET - it is up to you to source appropriate components and complete the build. The following items are supplied:
- 2x5 pin Eurorack power header
- Power cable
- 8x SD101C Schottky diodes for the diode stages (use 1N4148s for everything else).
The BOM and schematic can be found here: https://github.com/yorkmodular/dws