Originally conceived in 2014 as a limited-run side project by ALM Busy Circuits, the Fizzle guts is one for the heads... Its heart is a repurposed piece of digital-sampling history: the Casio FZ1 filter chip. This specific hardware gives the module a sonic signature that is difficult to replicate, a "murky," lo-fi warmth that can transition from smooth, dark sweeps to aggressive, squelchy resonance in an instant.

The module features two independent filter cores (A and B), each equipped with dedicated manual and voltage-controlled resonance and cutoff. Beyond filtering, the Fizzle guts includes a "DCA" (Digitally Controlled VCA) for each channel and a dedicated Mix output for summing the two paths. When pushed with high modulation rates, the filter is known for its "squeaky" and "blippy" artifacts, making it a perfect choice for those who prefer "weird" and unpredictable analog textures over clinical precision.

While the design is now open-source, these specific units have been professionally assembled by a trusted partner to ensure high-quality performance from this classic ALM design.