Erica Synths Acidbox III Filter

In the eighties, you were nothing if you didn't have a TB-303 module: a mainstay of first-wave acid. A few decades later, and we're treated to the Erica Synths Acidbox III. This is a sort of next-step in the 303-style evolution, and while it's not the full-grown synthesizer that the 303 was, this filter can be used to tweak any signal to taste. Feed it the sound of a synth or even the sound of a guitar and it's squeezed through an envelope filter with an LFO to satisfying effect. While it doesn't offer a mass of features, it definitely gives you the essentials, and wraps them all up in a clear and quickly-workable package that's been 100% designed for the modern age of acid.