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Bzzz pedal, front view - a neon-yellow-green enclosure with four chunky blue-and-silver knobs in a 2x2 grid, a small green LED beneath, a 3PDT footswitch at the bottom, and BZZZ hand-lettered in teal marker under the knobs.

Resonant Filter / Boost · One-off prototype

Bzzz

Filter / Boost Available · 1 of 1

If you know the Zappa “Hot Rats” solo tone, or the way Prince's guitar sings on “Purple Rain” - that's a Systech Harmonic Energizer, or something very like one. Bzzz is my take on it, built on PedalPCB's Zapper. It's a resonant filter with a boost baked in - like someone parked a wah at exactly the sweet spot and turned the level up. Four knobs (Volume, Gain, Frequency, Bandwidth) let me move that sweet spot around and pinch or open it up. It sings, it stings, it barks. I painted it neon yellow-green because that's what it sounds like inside my head.

  • TypeResonant filter / boost
  • ControlsVolume, Gain, Frequency, Bandwidth
  • CircuitPedalPCB Zapper (Systech Harmonic Energizer)
  • Enclosure125B
  • Weight~8 oz
  • Power9V DC, center-negative
  • BuiltJul 2026
  • StatusAvailable - one of a kind
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What it does

Bzzz is a resonant boost - not a fuzz, not a wah, not an EQ, but a little of each. The circuit lifts a narrow slice of your signal's frequency spectrum and boosts it hard, then feeds the whole thing through a gain stage. The result is a vocal, honky, singing tone that parks anywhere from low-throat to nasal-piercing depending on where you set Frequency and Bandwidth. Push Gain and it starts breaking up into a rasp - always musical, never fizzy.

Especially good stacked in front of a fuzz or a driven amp, where the filtered peak focuses the whole tone into a laser. Also great on its own for singing, cocked-wah lead voices.

Demo

Demo video coming soon.

Controls

Volume
Output level - from unity up through a healthy lift.
Gain
Drive into the filter. Cranked, it's a rasp; backed off, it's clean and glassy.
Frequency
Where the resonant peak sits, from throaty low-mids up into nasal treble.
Bandwidth
How wide or narrow that peak is. Narrow reads piercing and vocal; wide reads as a broad boost.

Circuit: PedalPCB Zapper, a modern build of the classic Systech Harmonic Energizer. Built, painted, and finished by Onion Madder as an original one-off - not affiliated with, endorsed by, or a clone of any commercial brand.