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Dual Analogue Transistor Ladder Filter


Dual Analogue Transistor Ladder Filter

The sound of an analogue 4-Pole Transistor Ladder Filter has been hailed for decades. Synth lovers and music fanatics around the world fell instantly in love with its sound.

With Filton, you can inject the rich characteristics of a true analogue 4-Pole Ladder Filter with Transistor drive into your Eurorack setup. This 20HP module delivers two discreet filter signal paths that can also run in a stereo mode. With its carefully designed user interface, Filton allows direct control access to all important parameters.

Filter audio with the powerful sound of true analogue dual transistor ladder filter circuitry, inherited from Modal’s legendary 002 synth

Morph seamlessly from four pole 24db per octave lowpass through bandpass to one pole 6db per octave lowpass

Gain thick and warm timbres with saturated transistor overdrive and resonant harmonic peaks

Process two input signals or one stereo signal through two discrete filter paths, with individual or summed audio output

Connect four analogue CV sources to control FM, Resonance, Morph and Level, plus pitch tracking by the 1V/Oct input

Integrate it with its sleek 20HP matte powder coated aluminium panel into your Eurorack system


Back for Good

Modal has a vital history in designing a modern transistor ladder filter, used in legendary products, like the Modal 002 and 001 synthesisers. The vibrant harmonics and smooth transistor drive deliver precisely the sound that demanding sound designers and musicians want from a modern reincarnation of this classic filter concept.


Filton’s transistor filter drive delivers organic textures ranging from warm subtle saturations to thick overdriven textures. Ideal for sound design, this dials in resonant harmonic peaks that can push sounds over the edge.


Filton’s polesweeping capabilities exceed the limitations of traditional filter designs and provide a playground for sculpting new and unusual sounds. Morph seamlessly from a 4-Pole Lowpass to a 1-Pole Highpass characteristic and turn the sonic content of your music upside down.

Audio In and Out

With carefully designed signal paths, Filton enables flexible patching options. Because Filton houses two discreet signal paths, you can process either a stereo signal, two mono sources independently or one mono signal in series or parallel processing.

Take Control

Each filter features an audio input, four analogue CVs with attenuverter controls for FM, Resonance, Morph and Level, pitch tracking provided by the 1V/Oct input, an audio output and a mixed output. All CV inputs on Filter A have been normalled to Filter B, meaning any CV signal plugged into Filter A is automatically sent to Filter B if nothing is plugged into the corresponding input.

Built to last

Filton comes with a sleek and stylish white 20HP matte powder-coated aluminium panel to fit right into any standard Eurorack system. The premium controls and connectors guarantee worriless operations for years to come.


  • Dual Analogue Transistor Ladder Filter Module
  • 2 x 24dB per octave four pole transistor ladder filters, with some very unusual morphing characteristics or ‘polesweeping’, enabling transition from four pole through bandpass to one pole 6db per octave, or anywhere in between
  • Processes two sound signals independently or allows for series or parallel processing of a single source
  • Saturated transistor drive with LED indicator when filter input level reaches drive threshold
  • 4 x controls for Cutoff, Resonance, Morph and Level per filter
  • 2 x analogue FM CV inputs per filter, one with 1v/oct pitch tracking and one exponential with a bipolar attenuvertor
  • Analogue CV inputs for Resonance, Morph and Level with a bipolar attenuvertor per filter
  • All CV inputs on Filter A have been normalled to Filter B meaning any CV signal plugged into Filter A is automatically sent to Filter B if nothing is plugged into the corresponding input
  • 1 x audio input with LED indicator and 1 x audio output per filter plus 1 x mixed output
  • Matte powder coated aluminium panel
  • Power: Standard +/-12V with 10 pin header
  • +/-5V for CV inputs
  • 20HP Eurorack