A Filter of Crows

Multi-Mode Overdrive Filter

A Filter of Crows is a unique filter module that builds on the concept of the highly sought-after Safari Series #1 module, “Crow”. It combines three 100% analog Pittsburgh-designed technologies.

Ultra-High_Gain Preamp
The first is an ultra-high-gain preamp circuit. The preamp, taken directly from the original Crow offers a unique up to 75x of variable gain overdrive. This circuit provides unmatched dimensions of overdrive without sounding harsh. Additionally, the circuit can be completely bypassed to allow for a completely clean exploration of the other aspects of the module.

PGH Filter
Next is a 12db State Variable “no-dead-spot” Filter, our classic PGH Filter with manually selectable and stackable filter responses. Lowpass, bandpass, and highpass filter responses can be enabled or disabled individually for instant parallel processing.

The PGH filter has been continually refined over the last 12 years of research and altered to fit the demands of each system that it has been a part of. One of its unique defining characteristics is its ability to offer a complete sweepable range without any noticeable dead spots. Dead spots are uneven / muted portions of the swept range due to non-linearities in the circuitry. The PGH filter has no noticeable dead spots and is voiced to interact well with the high-gain preamp circuit. The result is a rich, even, fully sweepable range.

Resonant Stability Circuit
Lastly is our Resonant Stability Circuit. This circuit enables the PGH filter to provide near-infinite resonance without slipping into self-oscillation, unless the user wants it to. Set to stable, Crows will not self-oscillate. It operates as a clean, organic filter. Set to unstable mode, the character of Crows changes dramatically. At normal settings, the incoming signal modulates the self-oscillating filter to produce harmonically complex sounds. In more extreme settings, Crows will start to struggle with controlling the oscillating resonance, adjusting the resonance shifts from ringing fuzz to heavy distortion to an extremely musical total failure.

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