Pittsburgh Modular - Filter

The Filter is a voltage controlled, analog, state variable filter designed by Pittsburgh native and electronics experimenter Michael Johnsen. The state variable topology was chosen because it allowed us to produce a very smooth and natural sounding filter, in addition to offering several other modes of operation, each with a unique sound and energy all their own.

There Is No Sweet Spot
This Filter defines the sound of Pittsburgh Modular. It offers a warm, organic sweep through the full frequency range. The lowpass filter is gummy and relaxed while the highpass is clean and defined. The goal was to produce a filter that did not have a sweet spot; where the every turn of the frequency knob produced something interesting.

Modes of Sound
Multiple filter responses are available simultaneously including lowpass, highpass, and bandpass. The fourth filter response is a variable response that shifts between lowpass, notch, and highpass.

Switch It Up
Two switches, Gain and Mode, further expand the capabilities of the Filter. The Gain switch modifies the functionality of the Q while the Mode switch toggles between filter and oscillator modes. Setting the Gain switch to "1" converts the Q setting into a VCA circuit for the audio input. Switching the Gain switch to "Q" returns the standard filter Q response.

Mode switches between Filter and Oscillator modes. Set to "Filter", the Pittsburgh Modular Filter will not self oscillate. Set to "Oscillator" the Filter produces a high quality voltage controlled sine wave. Adjusting the Q while in Oscillator mode modifies the shape of the waveform. At more extreme settings the Q adds anything from warm fuzz to heavy distortion the incoming audio.