Electro Harmonix Pico Swello Attack Filter

From the Legendary POG2 to a Pico Format Dedicated to Swell

The Pico Swello captures the spirit of a highly sought-after effect: the Attack of the POG2, which has become essential for transforming a guitar's attack into a gradual rise, more "bow-like," without a choppy effect. Electro-Harmonix isolates this here in a dedicated pedal, in Pico format, adding a low-pass filter section to enrich the volume envelope with a true tonal sculpting dimension. The result: a modern tool designed for busy pedalboards that goes straight to the point while remaining surprisingly expressive.

Who Is It For, Which Styles, and In What Contexts?

The Pico Swello is aimed at both intermediate guitarists and seasoned musicians who want an immediate swell pedal without complex settings. It shines in ambient, post-rock, indie, worship, pop, and texture-based music, but is equally relevant in blues or rock whenever rounder attacks and a "legato" feel are desired.

In the studio, it thickens a take and "glues" notes into the mix. Live, it helps transition from precise rhythmic playing to evolving soundscapes with a footswitch tap. It naturally works with a standard pedalboard and integrates very well before delays and reverbs to achieve cleaner and more majestic tails.

Controls, Modes, and Operation: Simple but Very Musical

The ergonomics are intentionally minimalist: ATTACK controls the rise time (from quick smoothing to long swell), and VOL adjusts output level to compensate for perceived volume loss when the attack becomes very slow. The filter section is controlled with FREQ (cutoff frequency) and MOD (modulation depth and direction, for sweeps upward or downward).

The FILTER button activates the low-pass filter and allows resonance selection: filter off, filter on with light resonance, or filter on with stronger resonance. Crucially, the modulation timing is linked to the ATTACK setting, making the whole very coherent under the fingers. Modulation is neutralized when MOD is centered, convenient for instantly switching from a "pure" swell to a more moving swell.

Sound Character

The Pico Swello delivers that "no pick" character reminiscent of a bow attack, automatic volume, or a perfectly controlled volume pedal, but with polyphonic tracking that preserves chord clarity. At light settings, it smooths the attack while maintaining articulation: perfect for delicate arpeggios, fast passages, or taming an overly percussive guitar.

When ATTACK is pushed, notes transform into wide, cinematic swells. With the filter, you move from a transparent swell to darker, more synthetic textures, even to envelope movements that breathe with the playing. The DNA of this effect comes from the POG2, a classic seen on pedalboards of artists like Jack White, John Mayer, Kevin Parker, Mac DeMarco, or John Squire: the Swello reprises the idea of a treatment that doesn't just add an effect but changes the playing feel and how the note "enters" the sound.

Technical specifications

Effects	Envelope / Auto-wah	Type	sector
Technology	Digital	Use	electric guitar
Format	Pedal	Color	White
EQ	Tone

Effect Type	polyphonic attack envelope (auto swell)	Input	6.35mm Jack (mono)
Polyphony	each note receives its own independent attack envelope	Output	6.35mm Jack (mono)
Compatibility	works with electric guitar and standard pedalboard	Power Supply	5.5 x 2.1 mm coaxial connector, center negative
Circuit	digital	Dimensions	approximately 51 x 93 x 51 mm
Bypass	buffered bypass	Weight	approximately 0.54 kg
Audio	mono	Power Adapter	included
Controls	VOL, ATTACK, FREQ, MOD	Required Voltage	9V DC
Control	FILTER button (filter activation + resonance selection)	Consumption	100 mA
Filter	low-pass filter with selectable resonance and envelope modulation	Battery Operation	no
Modulation	depth and direction controllable via MOD