Pittsburgh Modular LPG
Triple Mode Filter, VCA, Lopass Gate
The Pittsburgh Modular Lopass Gate module is a new take on a classic. Our intention was not to clone but to reengineer and expand on the original idea. Our module includes an amazing new self-oscillating resonance circuit and a quieter vactrol based VCA circuit with true unity gain. Voltage control of the module is handled using an invertible, attenuated input and ping input. The ping input takes any gate or square wave and converts it into a very tight trigger used to ping the vactrol.
In lowpass filter mode, frequency sweeps are warm and buttery and resonance is smooth and controlled until it gets near self oscillation. At this point the Pittsburgh Modular LPG module turns into a shouting beast. High resonance creates an edgier, shattered, more direct sound. It never loses control but is always teetering on the edge. Having both the smooth and snarling responses available creates a filter that is perfect for almost any situation.
In VCA mode, we worked very hard to reduce the bleed associated with most lopass gate circuits without resorting to tricks like adding an a traditional VCA after the vactrol circuit. After considerable effort, we succeeded in creating a vactrol based VCA that is identical or better in performance to our 2164 based Dual VCA module.
All the work we did on the filter and VCA come together with the lopass gate mode. The buttery warmth of the filter teams with the best attributes of the vactrol based VCA to create an impressive take on the original lopass gate.
LPG CONTROL DESCRIPTIONS
Frequency Control Knob:
In filter mode, the frequency knob controls the center frequency of the filter. In VCA mode, the frequency knob controls the pass through signal level. In lopass gate mode, the frequency knob controls both the center frequency of the filter and the pass through signal level.
Resonance Control knob:
In filter mode, the resonance knob controls the amount of resonance. In VCA mode and lopass gate mode, the resonance knob is not active.
Switch between the 3 module modes. VCA position (up) enables VCA mode, LPG position (center) enables lopass gate mode, and FILTER position (down) enables low pass filter mode.
Frequency CV Input Control Knob, CV Input, and Invert Switch:
CV input controls. The CV input knob attenuates the incoming cv signal. Invert switch inverts the incoming CV signal.
Gate or trigger input used to ping the vactrol and quickly modulate the frequency of the module.
- Size: 8hp
- Module depth with ribbon cable attached: 36.5mm
- Power Usage: +12v 20mA, -12v 20mA. Does not require +5v.