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.
