User manual

4075 Filter Module
Description
The 4075 filter is a voltage controlled, discrete analog, 24/db/oct cascaded transconductance low-pass filter, employing hand-
matched transistors. In its lowest FREQUENCY setting it shaves off higher frequency harmonics; its RESONANCE or “Q” circuit
pushes those harmonics past the self-oscillation boiling point, projecting a thumpy, thrashing squeal, with explosive low to mid-
range power and depth. The design is actually pulled from the four-pole ARP 4072 (better: more parts and trims), sans the
12kHz design flaw which hamstrung the original’s high end. The 4075 name has stuck—no correcting our little misnomer.
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Our 4075 filter is the most requested of the Boomstar filter models, perhaps owing to its uniqueness. Has there ever been a
better match for a square wave? It weaves dreams with “glidey,” 70s basslines, is a natural in the lead department, and feels
as if a temper tantrum simmers a mere micron beneath its veneer of faux respectability. Aggressive and articulate, this fresh
ARP can snap punishing kick drum sounds out as well as color with bright, edgy, stringy tones for essential arpeggiations.
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Potentiometer Potential
Three attenuverter and four attenuation pots control the FREQUENCY, RESONANCE, FREQ CV 1, RESO CV, FREQ CV 2, INPUT
and OUTPUT, delivering smooth, detailed, and complex expression.
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Switch It Up
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Classic Minimoog FULL and HALF strength filter frequency keyboard/voltage tracking for rounder low end with brilliant highs.
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Patch It Up
Seven patch points: 1 V/O, FREQ CV 1, FREQ CV 2, RESO CV, INPUT and 2x OUTPUT direct the deepest manipulation.!
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