The Euterpe Vertice Analogue Filterbank is a 4U, 19″ rack-mountable, hand-built, fully analogue filterbank, featuring three customisable 12dB/octave Sallen-Key filters, CV control, loopable ADSR envelope, overdrive and VCA distortion stages, handcrafted Italian wooden cheeks, and audio-grade through-hole components.

Handcrafted Analogue Engineering

The Vertice Seconda Serie represents an uncompromising approach to analogue sound processing. Euterpe built it entirely using through-hole audio-grade components, soldered by hand on Italian-made PCBs, housed in a rugged chassis with handcrafted wooden side cheeks. There is no automation or CNC machining involved in its construction—each unit embodies old-world craftsmanship. Even the cosmetic details echo 1970s design, with Bakelite knobs, submarine-style switches, chrome handles and retro brown-and-orange panel printing.

Vintage Filters with Modern Routing

At its core, the Vertice features three multi-mode 12dB/octave filters based on the Steiner-Parker Synthacon’s Sallen-Key architecture, originally designed by Nyle Steiner in 1974. Each filter includes low-, band- and high-pass modes, adjustable cutoff frequency, and emphasis (resonance). Users can switch between Diode and Transistor resonance types per filter—Diode providing sharp, soaring tones and Transistor delivering heavier, metallic textures. These filters can be arranged in series, parallel or stereo configurations, routed through mono and stereo outputs available on both front and rear panels.

Comprehensive Gain Staging and Distortion

Each of the three filters has its own dedicated audio input with gain control, allowing users to push the preamps into musical overdrive at around +17dB. Filter A includes an additional distortion circuit, delivering a massive +40dB gain for aggressive tonal shaping. The output VCAs also allow for further distortion, controlled via the ‘staccato/continuo’ knob or modulated with a control voltage through the amplitude modulation (AM) input. These gain stages enable rich analogue overdrive across the signal path.

CV Control and Envelope Modulation

The front panel provides extensive CV control over each filter’s frequency, with attenuators for precise modulation. The master frequency also accepts two CV inputs—one with an attenuator, the other with a V/Oct input, although chromatic accuracy is limited. A built-in loopable ADSR envelope can be triggered via button or gate input and includes three time ranges (percussive, smooth, slow). It can modulate either the master cutoff frequency or output VCAs, and users can invert or loop the envelope for additional modulation complexity.

Stereo and Summing Capabilities

While Vertice is ideal for mono signal shaping, it also offers stereo processing by routing audio through Filters A and B independently. This configuration can generate subtle or extreme stereo imaging depending on filter settings. Additionally, users can employ the unit as a summing mixer—combining stereo inputs on Filters A and B with a mono signal on Filter C for layered analogue colouration.

Connectivity and Modulation Integration

On the rear panel, users will find direct outputs for Filters A and B, a master stereo output, and an envelope output—ideal for complex patching or integration with modular systems. The unit handles CV ranges up to ±10V without issue, and audio-rate modulation yields everything from harmonic expansion to chaotic sidebands when patched into the frequency CV inputs.

Sound Quality and Build Philosophy

Every switch, knob, and control element on the Vertice contributes to a tactile and precise experience. There is no signal bypass; every input undergoes analogue processing that imbues character, even with conservative gain settings. The build and tonal results reflect a philosophy rooted in analogue purity—no digital compromise, just warmth, saturation, and dynamic responsiveness reminiscent of 1970s studio gear.