Passive Low Pass Gate in 1U

Natural dynamics with the magic of vactrol's. Drop this module (or a few of them) into your 1U row, patch in some sound sources, and then ping them with gates and CV to get some instantly pleasing results. So simple and fun! The Intellijel Passive Low Pass Gate 1U is a simple, DC-coupled, vactrol based, 1-pole passive low pass gate, which is controlled by an external CV input. Without positive control voltage, the gate is completely closed and none of the LPG’s input signal is passed through to the output. Increasing amounts of positive CV open the gate — making the output signal both louder and brighter. At +5V, the gate is fully open and the input signal is passed through to the output. This makes LPGs sound very different (and more “acoustic”) than the traditional complement of envelopes, VCFs and VCAs that are employed in most subtractive synthesizers. Exciting the vactrol (via the CV input) with a trigger, noise blast, or short envelope will result in a very natural sounding filtered envelope that’s reminiscent of the sonic characteristics of struck objects, which are allowed to decay naturally.

In addition, because this is a passive circuit (no power is applied to it), its sonic characteristics are somewhat dependent upon the audio signal you feed into it, making it a very natural and organic way to shape a signal’s volume and tone.

In the Box
• The module itself