Attack Decay

This is the overall loudness knob for the effect. Because volume-shaping effects can end up much quieter or louder than your bypassed signal, you'll use this to match levels.

tip: This knob has a lot of gain available, so it can push things into clipping/distortion. If you hear unwanted crackle or breakup, turn VOL down and it usually clears up.

This is your 'how much effect vs. how much clean guitar' knob. Fully clockwise is all effect and no clean; counter-clockwise brings your natural guitar tone back in underneath.

tip: BLEND secretly does two other jobs depending on secondary modes: in Harmonix Blend mode it mixes clean vs. fuzz before the envelopes (recreating the vintage 'Harmonics' knob), and in Return Blend mode it mixes the RETURN jack signal against the shaped output. See the secondary modes.

This controls how slowly each note fades in. Low settings = the note appears instantly; high settings = a slow, ghostly swell like a bowed violin or a backwards recording. All the way down turns the swell off.

tip: For the classic backwards/swell sound, keep ATTACK in the 10 o'clock–noon range and DECAY maxed. In Poly mode the knob positions do NOT match Mono mode's timing, so re-dial by ear.

This controls how quickly each note dies away after it fades in. Short settings chop notes into snappy staccato stabs; long settings let notes ring longer. All the way up (maximum) turns the fade-out off completely.

tip: For pure swell effects, keep DECAY at maximum (off). For short, plucky, staccato 'stabs' turn it down. Combine a fast Attack with a fast Decay for percussive blips.

This tunes how easily your playing sets off the effect. Turn it up and even soft notes trigger a fresh swell; turn it down and only harder plucks trigger. Use the flashing P LED to help you dial it in.

tip: In Poly mode, maxing SENS produces intentional bubbling noises — that's normal. In tremolo (Continuous Envelope) mode, set SENS to minimum for a free-running tremolo that doesn't restart every time you pluck.

This is the fuzz intensity knob — how dirty and saturated the distortion gets. More clockwise = more grit and sustain.

tip: Maxed out, the fuzz gets very noisy when you're not playing. If that bugs you, back it off to about 4 o'clock. Turning it down from max may briefly mute the signal for a split second — that's normal.

The fuzz's treble control. Turn it up for a brighter, cutting fuzz; turn it down for a darker, rounder tone.

tip: Only affects the sound when the fuzz is switched on; it does nothing to your clean signal.

The loudness knob just for the fuzz. Because this fuzz can get very loud, this lets you balance it against your clean tone.

tip: Start it low, around 9 o'clock, until you get a feel for it. If you use the pedal purely as a fuzz (taking output from the SEND jack), H.VOL becomes your master volume.

The big personality switch. Off = one volume shape for everything you play (traditional, like the vintage unit). On = every note gets its own separate fade, so chords and arpeggios shimmer and cascade independently.

tip: Poly mode also doubles as a shortcut key for entering many secondary modes (hold POLY plus other buttons). It's normal for Poly mode to make bubbling/waterfall noises, especially with both Attack and Decay active or with the fuzz on.

Three memory slots for your favorite complete setups. Tap to recall a saved sound; hold to save what you're hearing now. Tapping a lit preset again returns you to live (WYSIWYG) mode.

tip: If you tweak a knob after loading a preset, its button blinks to show it's been altered — tap it once to snap back to the saved version, or hold to overwrite. Presets save nearly everything: knobs, expression sweep, Poly/Harmonix state, envelope curves, tremolo, blend modes and more.

The main on/off stomp. Light on = effect active; light off = clean bypassed guitar. It's also the 'hold this first' button for entering most of the pedal's hidden modes.

tip: In Manual Trigger mode this footswitch fires the volume envelope on each tap instead of your playing; in that mode, hold it 2 seconds to actually bypass. Hold it while powering up to do a factory reset.

Normally your fuzz stomp. But you can convert it into a preset-scroller: each tap then steps through Preset 1, 2, 3 and back to your live sound. It's also used in combos to enter tremolo mode.

tip: When switched to preset-cycle duty, your current fuzz on/off status gets saved into the live mode. This footswitch role is remembered after power-down but is not saved per-preset.

Simple indicator: lit means the fuzz is on. The three small fuzz knobs only do anything when this light is on.

Your visual metronome for pluck detection — watch it flash to see whether the pedal is 'hearing' each note, which makes setting SENS much easier. If it's solid, your left footswitch is in preset-scrolling mode.

tip: If it isn't flashing when you play (in Mono mode), turn SENS up until it does. Remember it stays dark in Poly mode even when things are working.

Turns the pedal into a rhythmic volume-pulsing tremolo whose shape and speed you set with the Attack and Decay knobs. It restarts each time you pluck, unless you set SENS to minimum for a free-running pulse.

tip: In Poly mode this same mode sounds like cascading filters rather than a normal tremolo. It's saved per-preset and set independently for Mono and Poly.

Lets you blend clean and fuzzy tone together and then run that mix through the swells — great for bowed-instrument sounds with body and grit. When you exit, BLEND goes back to its normal wet/dry job.

tip: The blend amount is saved to presets. You can even assign an expression pedal to sweep this blend while in the mode.

When using the effects loop, this lets you dial in how much of the looped/return signal you hear versus the shaped output. Handy for parallel-style textures.

tip: Only works when something is plugged into RETURN. The setting is saved to presets.

Changes what you hear when the pedal is off: instead of your normal input passing through, the effects-loop return signal is what comes out. Useful for certain loop routings.

tip: With Return Bypass on, the fuzz is NOT sent out the SEND jack while bypassed, even if the fuzz is switched on.

Lets you decide by foot exactly when each swell happens instead of the pedal listening for your pick. Tap to fire a swell; to actually bypass in this mode, hold the footswitch for 2 seconds.

tip: Saved per-preset. Great for dramatic, perfectly-timed swells where you don't want note dynamics triggering things.

The compressor evens out your playing volume so sustained notes keep feeding the swell engine. Turn it off for a rawer, more dynamic response. You can set it separately for Mono and Poly modes.

tip: Saved per-preset. Leave it on for smooth, even swells; try it off if you want more natural dynamics.

Fine-tunes the 'feel' of the fade-in and fade-out — whether the volume ramps in a straight line, eases in gently, or does a smooth S-shape. Only affects Mono mode.

tip: Parabolic (default) gives the most natural swell for most players. Saved per-preset. These curves do nothing in Poly mode.

Decides whether the fuzz hits your signal on the way out to your other pedals, or on the way back in from them. Lets you control where the dirt sits relative to your loop.

tip: If you're not using the RETURN jack, the fuzz just appears on the SEND signal as normal. Saved per-preset.

A full wipe that returns everything to how it left the factory — erasing all your presets and custom settings.

tip: Defaults after reset: expression controls VOL, tremolo off, parabolic curves, clock/manual triggering off, compressor on, fuzz before SEND, Return Bypass off, and both special blends set to 100%.

Where your guitar (or the pedal before it) plugs in.

tip: Place this pedal near the front of your chain so pluck detection works right — after a compressor or pitch shifter is fine, but before distortions and wahs is best.

The main output to your amp or the next pedal.

An output that sends your signal (with fuzz, if on) out to your own pedals before the volume-shaping happens. Pair it with RETURN to loop other effects into the swell engine.

tip: You can use SEND as your main output to run the pedal purely as a fuzz box — then the HARMONIX footswitch is your on/off and H.VOL is your master volume; VOL, SENS, ATTACK and DECAY do nothing in that setup.

Where you bring signal back in to be volume-shaped. Whatever's here gets the fade-in/fade-out treatment. Clever trick: plug a second instrument in here and have your guitar at INPUT trigger the swells on it.

tip: In Mono mode your guitar at INPUT can trigger the envelope while the RETURN signal is what actually gets shaped — great for taming pedals (like big reverbs or fuzzes) that normally smear the attack.

Plug in a rocker pedal or a modular/CV signal to sweep the knobs with your foot or another device, or feed in a clock to trigger swells in perfect time. Every knob can be assigned.

tip: Wiring must be Sleeve=heel, Ring=toe, Tip=wiper. Suggested pedals: EHX Expression, Moog EP-3, Roland EV-5, Boss FV-500L. After a factory reset, the expression pedal controls VOL by default.

Where the power adapter plugs in. This pedal is thirsty — it needs at least 140mA, so a typical weaker 9V supply won't cut it.

tip: Using an adapter rated below 140mA, or with the wrong polarity, causes unreliable behavior and can damage the pedal and void the warranty. Stick with the included supply.

Lets an external device like a drum machine or modular clock fire the swells in perfect rhythmic sync. When enabled with a plug in EXP, your normal pluck detection is switched off.

tip: Remove the EXP plug or disable this mode to get automatic pluck detection back. The setting is saved per-preset.