Pulsers

A-101-1 Vactrol VCF Vintage Edition

Vactrol multitype input filter (Steiner)

Doepfer · 16 HP · U3

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A-101-1 VACTROL VCF
Vactrol Multitype Input Filter
CVF In 1
CVF In 2
CVF In 3
CVQ In 1
CVQ In 2
Frequ.
CVF2
CVF3
Emph.
CVQ2
LP
BP
HP
LP In
BP In
HP In
Out1
Out2
LP + BP + HP =
Notch

Panel · 81.3 × 128.5 mm Drag to explore →

Description

Doepfer's vactrol filter after Nyle A. Steiner's 1974 design: three audio inputs, one each for low pass, band pass and high pass, filtered and summed to a common output. Vintage Edition: black panel, black knobs with turned aluminium caps.

Key features

  • Three audio inputs with attenuators (LP, BP, HP), normalled LP to BP to HP; the same signal in all three gives any mix of the three responses, including a notch
  • Vactrols set frequency and resonance, so both are voltage controlled: three frequency CV inputs (two with attenuators) and two resonance CV inputs (one with attenuator)
  • Resonance (Emph.) up to self-oscillation
  • Out1 is the original circuit, whose level rises with resonance; Out2 compensates that rise with an additional vactrol
  • Two LEDs show the frequency and resonance control, the light inside the vactrols

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