The latest additions to my setup are two STG Soundlabs modules, the Wavefolder and the Sea Devils filter.
Both circuits are based on Yves Usson designs.
The first, as its denomination suggests, will "fold" any incoming signal. By doing so, the Wavefolder will output a more complex signal and produce new harmonic content. Obviously , it works best on simple waveforms of audio signals. There's an Offset control that will determine at what "level" of the waveform the folding will occur. For instance, by adjusting the Offset appropriately, one could apply folding only onto the positive period of a bipolar signal. Fold mix control makes the balance between the original signal and the folded signal. Gain control is a VCA on the input stage of the folding circuit.
Voltage control is provided for Gain (with attenuator) and Offset.
Basic application of the Wavefolder is to render a rather dull waveform more harmonically rich.
Wave folding can produce comparable results to those obtained with wave shaping or wave multiplying.
The Wavefolder is not a module I use very often but its use can be very rewarding if set up correctly.
The Sea Devils filter is a diode ladder design inspired by the circuit found on second generation EMS Synthi A and AKS, with a 24dB slope.
As its pedigree suggests, that filter has bags of character, it "sings" very well at high resonance settings, with a huge frequency range and it tracks quite well to 1V/Oct...that makes the SDF a great sine oscillator to provide powerful bottoms with good definition and crispy, precise highs.
Also, it responds very well to fast, audio rate frequency modulation.
Volume drop at high resonance settings is not too obvious and there are lots of sweet spots just before and after the point of self oscillation.
At high input levels, the SDF delivers smooth saturation, which is very nice.
Voltage control is provided for Resonance, there are two 1V/Oct frequency modulation inputs and there's one scalable frequency modulation input with attenuator.
All of this makes the SDF my favorite in my current setup. I love it even more than the Analogue Systems RS-500e, which is also an EMS based diode ladder filter circuit.
Both modules are 14hp and benefit of roomy front panels. They are quite deep, so they won't fit into a skiff. Panel control layout is clear but positioning of the control input jacks can be somewhat confusing as they are not placed right next to or under their respective parameter. Build quality is excellent and working with these modules proves to be a very satisfactory experience.
Looking forward to grab a Post Lawsuit filter ...