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SKU: Instruō_.tràigh Maker: Types: ,


Transistor Ladder Voltage Controlled Low-pass Filter

Nothing quite beats the comforting sound of multiple rich sawtooths softened by a warm, squishy filter! The tràigh is based on classic discrete circuit designs pioneered by Moog in the 1970’s – a classic transistor ladder low pass filter with a -24dB/octave slope (4 pole). The only op-amps used are at the mixer summing stage and for buffering the output signal. Everything else is transistors and fuzzy caps. The approach in sonic character is vintage through and through and if you ask us, it sounds great. 

Input signals will hit approximate unity level when channel faders are at the midway point. Increasing them will add gain in a soft wave-shaped manner.

With resonance maxed out, the tràigh will self oscillate with a stable sine wave.

With rich input signals, the resonance will tighten up the cut-off slope and accentuate overtones from a soft squelch to full blown formant madness when a touch of FM is introduced.

tràigh | traːj | noun (coastal tide) the rising and falling of the sea due to the attraction of the moon, to ebb, recede, settle, empty



  • Transistor ladder circuit architecture 24dB/octave low-pass
  • 1V/octave, Coarse and Fine cut-off frequency controls
  • Linear FM with attenuator
  • Output with master output level control
  • 3 channel input mixer


  • Width: 18HP
  • Depth: 27mm
  • +12V: 40mA, –12V: 20mA