The Quantus Ampla from Noise Engineering is a 6HP Eurorack module that's a voltage-controlled amplifier and a voltage-controlled attenuator. They say that it has four channels of linear DC-coupled goodness for all your VCA needs: ducking, mixing, CV-controlled leveling, and more. Here's their brief description of it...
Quantus Ampla is a compact four-channel VCA. But it's not just any VCA: with some unique normaling, mixing, and CV options, you can use it for a plethora of tasks. Each channel has two modes: Amplify, which gives you normal VCA response, and Attenuate, which makes the VCAs close instead of open in response to positive CV. The CV inputs are circularly normalled, so you can easily create ducking effects over multiple voices, volume fades, and transitions, all with minimal patching. Plus, the outputs mix down, so it can be two two-channel mixers, a 3 channel mixer, a 4 channel mixer... Oh, and did we mention that it's DC coupled so it can process CV signals, too? The possibilities are endless.
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