Lowpass Filter PX-101

Name: Lowpass Filter PX-101
Brand: PastFX
Availability: OnlineOnly

Filter

Envelope Filter

Moog Moogerfooger MF-101 recreation with 2/4-pole filter, envelope follower, and expression input.

The PastFX PX-101 Lowpass Filter is a compact recreation of the discontinued Moog Moogerfooger MF-101, shrunk to less than one-quarter the size of the original (60 x 112mm vs 130 x 230mm). It uses an internal voltage converter for bipolar operation from a standard 9VDC supply.

Five external controls shape the sound: Drive adjusts input gain (with dual-color LED level indicator), Mix blends direct and filtered signals (clockwise = more filter), Resonance shapes the frequency response (capable of self-oscillation at extreme settings), Envelope Amount modulates filter cutoff intensity, and Filter Cutoff sets the operating frequency. A 2/4-Pole switch selects between brighter 2-pole or deeper 4-pole response, while a Smooth/Fast switch sets envelope follower response speed. An internal switch selects between true bypass or always-on preamp mode.

An expression pedal jack (50K-100K linear pot) can control Mix, Amount, Resonance, or Cutoff via internal DIP switch selection. Internal trimpots for sensitivity and frequency cutoff fine-tuning. 112 x 60 x 31mm enclosure drawing 120mA at 9VDC center-negative. Handmade in Brisbane, Australia.