instruo-aradh

Instruo àradh

Transistor ladder filter and VCA with envelope follower, comparator gate, and strike input in 6HP

6 HP Eurorack module

The àradh is a transistor ladder low-pass filter with an integrated VCA, building on the original Instruo tràigh design. It combines classic filter functionality with a VCA that can be routed pre or post-filter, an envelope follower with adjustable attack and release, a comparator gate output, and a strike input with variable decay for impulse envelope modulation. A user-definable CV input can target multiple parameters simultaneously via the CV Assign system, making it a versatile sound-shaping tool for both east and west coast synthesis approaches.

Features

  • Low-pass transistor ladder filter
  • Integrated VCA with pre/post-filter routing
  • Strike input with variable decay impulse envelope
  • User-definable CV input with primary and secondary parameter assignment
  • Envelope follower with adjustable attack and release
  • Comparator gate output with adjustable threshold
  • Self-oscillating resonance with auto-gain compensation
  • Audio-rate strike triggering for percussive effects
  • Factory reset via button combination

Controls & Jacks (15)

  • CV Attenuverter— Sets the depth and polarity of modulation applied to the targeted user-defined parameter from the CV input. Center position fully attenuates
  • Bias— Sets the level of the VCA. Center position provides unity gain with no CV present. Also sets the threshold voltage of the comparator.
  • CV/FM— Bipolar control voltage input for the VCA amplitude, filter cutoff, resonance, and/or decay time based on the CV Assign setting. Scaled by t
  • CV Assign— Assigns which primary parameter the CV input targets. Cycles through off (unlit), VCA (white), filter cutoff (amber), or both (white/amber).
  • Fc— Controls the cutoff frequency of the transistor ladder low-pass filter. At fully clockwise position, the filter self-oscillates and generate
  • 1V/Oct— Bipolar 1 volt per octave pitch tracking input for the filter cutoff frequency. Summed with the Fc knob value for keyboard tracking.
  • Q— Sets the resonance emphasis at the filter cutoff frequency. Auto-gain compensation maintains consistent output level as resonance increases.
  • Out— AC-coupled audio output from the low-pass filter and VCA.
  • Pre/Post— Configures VCA routing relative to the filter. Post (up) routes VCA after the filter for east coast style. Pre (down) routes VCA before for
  • Gate/Follow Out— Outputs either a comparator gate (0-5V) or envelope follower signal (0-8V) based on the Gate/Follow toggle position. Envelope source set by
  • In— AC-coupled audio input to the low-pass filter and VCA.
  • Decay— Controls the decay time of the impulse envelope triggered by the Strike input and Strike button. Also sets the release time of the envelope
  • Strike In— Gate/trigger input for the impulse envelope which modulates both the filter cutoff and VCA amplitude. Can be triggered at audio rate.
  • Strike— Manual trigger for the impulse envelope. Also used with CV Assign to access secondary user-defined parameters, envelope follower settings, a
  • Gate/Follow— Three-position toggle setting the output mode: up for comparator gate signal, center to disable, down for envelope follower output.

How-To Guides

  • East Coast Synth Voice
  • Impulse Envelope Ping

Explore the interactive àradh panel on BleepDex — tap any control to learn what it does.

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