Passive Dual LPG with Linked Two-Pole Resonant Filters - Herzlich Omen - 4hp passive dual LPG for Eurorack
The Omen is a dual LPG with a bit more than you might be used to. Like you, I once was lost in the world of low pass gates, seeking something more, something bigger and somehow juicier. The inspiration came to me as I was reading a particularly heavy book on passive filters, and I realized it was possible to make far more interesting LPG designs than the standard we've become so accustomed to.
In a convergence of old-school LPG design and more modern components, the Omen boasts two -6dB resonant filters, custom built vactrols, built in CV attenuation and no less than three cutoff modes per filter. Filter 1 is soft and light, imparting a gentle, naturally gated touch of filtering on your sound, while Filter 2 is darker and more resonant, and can turn downright growly and distorted when left wide open.
Designed to give you as many creative options as possible, the Omen has the unique ability to function as either two discrete LPG, or as one 4-pole resonant LPG. When plugging a signal in to Input 1, and with no signal plugged into Input 2, the output will be present at both Output 1 and Output 2, with Output 2 producing the signal as it passes through both filters. Tweaking both filters independently will generate a wide array of soft and sometimes harsh tones, ranging from Buchla bongos to early synthesis brass and organ sounds. There is much to love here.
CV is similarly handled, by plugging in only one CV source, it will act on both channels - this is useful for creating musically similar outputs as well as when using the dual filter operation. However, the dual filter mode greatly benefits from having two CV inputs: use an envelope in CV1 to act as a VCA, and an LFO in CV2 to create tremolo, for instance.
Using custom designed, hand built vactrols, care has been taken to mitigate the less desirable aspects of passive LPGs - in most modules, the user can expect zero bleed through on the LPG channels, and signal attenuation is minimal even with the 4-pole filter settings engaged. Of course, many of the natural features of vactrols remain, such as subtle memory effect when engaging the vactrol for long periods.
DIY enthusiast? Rejoice! The Omen is now available as a fully loaded DIY kit - everything you need to build your very own Omen packed in one place, so you can easily build one in the comfort of your own home. It is not a difficult DIY project, an ambitious beginner or someone with experience from a few easy builds can tackle the Omen in an afternoon. The build is all through-hole aside from three SMD components, which are easily soldered by hand due to their large size.
Finally, you receive maximum blinkenlights as LED's on the front panel simulate the action of the vactrols, so you'll always know what's going on under the hood. No collection of fancy LPG's is complete without the Omen.