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Twilight Pulse Audioworks Fluoreszent

Oct 28, 2026

The Fluoreszent is an optical sustainer/compressor from Twilight Pulse Audioworks, and it’s one of the few compressors I’ve tried that I’d describe as a sustainer first. Attack and release are fixed by the builder (fast attack, slow release), so there’s nothing to fiddle with there. What you get instead is a short list of knobs that all matter.

I liked it quickly. Compressors can feel like they’re taking over your picking, and this one was easy to set so it didn’t. It also runs at 18V internally, which the builder chose for headroom, and I never felt it squashing the top of my chords in the demo.

Controls

There are four knobs: SUST sets how much sustain you get, MSTR is the master volume, BLEND mixes the dry signal with the sustained one in parallel, and LUMIN is an active tone control that cuts or boosts the high frequencies. Noon is the neutral point for LUMIN, so I treated it as a way to fit the pedal to whatever sits around it. A single footswitch and an LED round out the panel.

One detail worth knowing: BLEND never goes fully dry. The builder keeps a minimum of roughly 15 to 20% of the sustained signal in the mix, so even at the low end you still hear a touch of the effect. I didn’t miss the fully dry position.

In the demo above I’ve set up sweeps for Sust, BLEND and LUMIN, so you can hear what each one does on its own. MSTR has no sweep, because it only changes level.

How It Sounds

The three main presets show the range I found. Sweet Sustain (SUST at 2 o’clock, BLEND all the way up, LUMIN just under noon at 11 o’clock) is the one I’d leave on all night: long, even note tails with the highs eased back a little. Clear Comp maxes out Sust and pulls BLEND back to noon, so you get the heavy sustain from the compressed signal but with the dry attack of the pick mixed back in. LUMIN sits a bit past noon there, at 1 o’clock, to keep it open.

Clever Boost goes the other way: SUST at just 10 o’clock, MSTR up at 2 o’clock, BLEND all the way up. That’s less about squeezing and more about a level lift, handy for pushing the front of an overdriven amp or pedal. The builder aims the pedal at exactly that job, with a thick lead tone when you feed it into drive. The SUST sweep runs from fully down to fully up, which makes it easy to hear where sustain turns into a more obvious squeeze.

Fluoreszent vs Keeley Compressor Mini

The Keeley Compressor Mini is the natural reference, since both lean transparent. The Mini has Level and Comp and sets everything else internally as you turn Comp up. The Fluoreszent also fixes attack and release, but adds a parallel BLEND and an active LUMIN control, so you can shape both how much of the compressed signal you hear and how bright it is. The Mini is the simpler, one-decision pedal. The Fluoreszent asks for a little more setup and gives you more tone-shaping back.

Who It’s For

If you want sustain on clean chords and lead lines without a pedal that announces itself, this is a good fit, and so is anyone who wants a smoother, thicker front end for an overdrive. The builder says it also works with bass and with acoustic guitars that have pickups, though I only used it on a Jazzmaster here. Look elsewhere if you want to set attack and release yourself, or if you want a dramatic, squishy compressor effect. The Fluoreszent is deliberately tuned to stay out of the way.

Specs

  • Type: optical sustainer/compressor
  • Fixed fast attack, slow release
  • Controls: SUST, MSTR, BLEND (never fully dry), LUMIN (active high-frequency cut/boost)
  • Runs at 18V internally
  • Works with guitar, bass and acoustic guitar with pickups
  • Not released yet; final specs (bypass type, power requirements, size) to be confirmed by the builder

Signal Chain

Where to Buy

Twilight Pulse Audioworks Fluoreszent
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Get detailed specs on Twilight Pulse Audioworks' website

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