Electro-Harmonix EHX Pico Swello Polyphonic Attack Envelope Guitar Effect Pedal

Electro-Harmonix Pico Swello – Polyphonic Attack Envelope Pedal

Overview

One of Electro-Harmonix’s most popular and beloved effects is now available as a standalone pedal. Derived from the legendary POG2, the EHX Pico Swello brings you its unique attack filter, applying an attack envelope to each individual note played—whether you're playing single notes or full chords. This creates a highly musical, multi-voice effect that adapts beautifully to any musical style. The polyphonic attack filter is the beating heart of the Pico Swello, generating lush swells and reverse sounds with the added bonus of a modulated low-pass filter for even more expressive, synth-like tones.

Why Choose the Electro-Harmonix Pico Swello?

• Standalone POG2 Magic: You no longer need a massive POG2 to get that famous, lush attack envelope effect. The Swello packs that exact same highly sought-after polyphonic attack filter into a compact, pedalboard-friendly pico chassis.

• Polyphonic Attack Envelope: Unlike monophonic envelope pedals, the Swello processes each note individually, even within complex chords. This creates a very musical, multi-voice effect that responds perfectly to your playing dynamics.

• Subtle or Dramatic Swells: Implemented subtly, the Swello adjusts your guitar’s attack to sound smooth and flowing, even during fast lines and arpeggios. Crank it up to create dramatic volume swells perfect for shaping gently shifting ambient soundscapes and synth-style pads.

• Expressive Low-Pass Filter: The built-in Low-Pass Filter (LPF) adds an entirely new dimension of musicality. You can create upward or downward filter sweeps that are tightly synced to your attack time, resulting in incredibly expressive tones.

Simple, Intuitive Controls

The simple 4-knob control layout is incredibly easy to dial in, starting with the heart of the pedal:

• ATTACK: The core of the pedal. Turn it up to go from a quick, gentle attack time to slow, long, sweeping swells.

• VOL: Controls the overall output and is useful for making up for the perceived low volume of long attack effects.

• FREQ: Adjusts the cutoff frequency of the Low-Pass Filter.

• MOD: Controls the depth and direction of the LPF envelope for upward or downward filter sweeps over a narrow or wide range of frequencies limited by the cutoff frequency. The LPF’s modulation timing is tied directly to the ATTACK knob setting.

• FILTER Button: Engages the LPF and selects between adjustable low and high resonance settings.

Key Features

• Compact Pico chassis saves valuable pedalboard space

• Standalone Attack Envelope effect originally from the EHX POG2

• Polyphonic attack envelope applies swells to each individual note played

• VOL adjusts overall output volume

• ATTACK adjusts the ATTACK Envelope Time from quick to slow

• Low Pass Filter with adjustable resonance and envelope modulation

• FILTER button engages the LPF and selects resonance settings

• FREQ sets the cutoff frequency of the LPF

• MOD controls depth and direction of filter modulation

• Power adapter included

Specifications

• Brand: Electro-Harmonix

• Model: Pico Swello

• Effect Type: Attack Envelope

• Circuit: Digital

• Bypass: Buffered Bypass

• Audio: Mono

• Power Supply: 9.6VDC-200mA power adapter included

• Dimensions (in): 3.65 x 2.0 x 2.0

• Current Draw: 100mA

• Year Released: 2025

• UPC: 683274012698

• Country of Origin: USA

Ideal For

• Ambient and Post-Rock Guitarists: Create massive, ethereal volume swells and synth-style pads without needing a volume pedal.

• POG2 Users: Save space on your board while keeping your favorite attack effect independent from your pitch shifting.

• Lead Players: Use the subtle attack settings for incredibly smooth, violin-like lead tones and effortless legato playing.

• Experimental Musicians: Dive into the modulated LPF to create auto-wah-style sweeps that perfectly track your playing dynamics.

Transform your attack into an expressive, flowing soundscape.