The ZVEX Candela VibroPhase is a candle-powered vibrato and phaser machined from solid brass and glass, and it is generally credited as the world's first candle-powered guitar effects pedal12. Designed and built by ZVex founder Zachary Vex, it was launched at the NAMM show in early 20162. Instead of a power supply or battery, a single tea-light candle lights two solar cells that feed the audio electronics, and its heat drives a small Stirling engine that creates the modulation3.
ZVEX describes the result in plain terms:
"The sound sweeps from subtle vibrato to Leslie-like phasing with a speed range wider than anything ZVEX has ever produced."
A vibrato and phaser run on a tea-light candle
The Candela VibroPhase is a "vibrophase" effect: a combination of phaser and vibrato character. ZVEX's specs say it creates a realistic 3D rotary speaker effect combined with phasing, wah, vibrato and tremolo effects, and produces a mono output5.
The circuit works optically, the way classic photocell-based vibe pedals do, but with a twist in how the light is modulated. As Gearnews explained at launch, the Candela uses a turning disc with black bits driven by a Stirling engine; a candle or tea light sits on one side of the disc, and an optical sensor reads the pattern from the other side6. Gearnews framed it as a vibe pedal that works using light and a classic photocell, just powered by candlelight2. ZVEX itself describes the build as a mix of 1800s technology, the Stirling heat engine, and 60s/70s audio circuitry1.
The enclosure is machined from solid brass and glass17, which is a large part of why it looks the way it does, and why it costs what it does.
How the Stirling engine sets the speed
The modulation speed is set mechanically, not by a knob. The candle's heat drives the Stirling engine, which spins the disc, and the speed of the flywheel can be altered by swinging a magnet toward its edge3. That magnet is the eddy current brake: Guitar Interactive Magazine describes it as a 1" diameter neodymium sphere magnet8.
There are two gear ratios on the Stirling engine that cover about a 20:1 speed range when used with the eddy current brake8. In practice, moving the magnet closer to the spinning flywheel slows it down through magnetic drag, and changing the gear ratio jumps between slow and fast ranges, which is what gives the pedal its unusually wide sweep from subtle vibrato up to fast rotary-speaker phasing.
Guitar Interactive Magazine noted who the design was aimed at:
"Designed for fans of the 1800s, guitar effects enthusiasts who have to have everything, and guitarists who want a wildly more adjustable take on the Univibe than has ever been created before."
From candle-powered original to pedal version
The Candela Vibrophase was introduced at Winter NAMM in January 20164, with ZVex launching it publicly that February and claiming it as the first candle-powered effects pedal2. It was hand-crafted, and Zachary Vex estimated a hand-crafted Candela would set you back $6,0003; German coverage later put the price between €6,000 and €7,0006. ZVEX's own product page lists the price as available on request from its sales email4.
| Version | Power | Price | Notes |
|---|---|---|---|
| Candela Vibrophase (2016) | One tea-light candle, 9V at 0.33mA from two solar cells43 | $6,000 estimated at launch3; €6,000 to €7,000 per German press6; price upon request per ZVEX4 | Solid brass and glass, Stirling engine, true bypass on separate foot switch14 |
| Vibrophase pedal (2018) | Conventional pedal power | $2699 | Compact, candle-free pedal based on the Candela concept7 |
The candle version looked glorious, as Delicious Audio put it, but was rather impractical, at least for the gigging guitarist, and it was later superseded by a pedal version7. That pedal version, the ZVex Vibrophase, is a compact conventional phaser and vibrato pedal built on the Candela Vibrophase concept9. ZVEX describes its sound as sweeping from subtle vibrato to Leslie-like phasing, with a speed range wider than anything ZVEX has ever produced4.
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Questions
Does the ZVEX Candela Vibrophase run on a battery?
No. It runs on a single tea-light candle. The candle illuminates two solar cells that produce 9 volts at 0.33mA for the effect's electronics, while its heat drives the Stirling engine that turns the modulation disc. There is no battery or power supply involved.
How long does one candle last in the Candela Vibrophase?
ZVex claims the pedal runs for nearly 5 hours off one tea light candle. That covers both the electronics, powered by solar cells lit by the flame, and the Stirling engine, which is driven by the candle's heat.
Is the Candela Vibrophase analog or digital?
It is analog. ZVEX describes it as a mix of 1800s technology, a Stirling heat engine, and 60s/70s audio circuitry, and press coverage at launch called it true analog technology. The modulation is read optically from a spinning disc rather than generated digitally.
Does the Candela Vibrophase have true bypass?
Yes. The bypass lives on a separate foot switch pedal, which contains a true bypass switch, one TRS jack for the Candela Vibrophase unit, and the input and output jacks for your signal chain.
Is the Candela Vibrophase still made?
It is not a high-volume product. ZVEX has described it as hand-crafted and priced upon request, and in 2018 the company released a conventional candle-free pedal version, the Vibrophase, listing at $269, as the practical alternative.
What does the Candela Vibrophase cost?
ZVEX lists the price as available on request from its sales email. At launch, Zachary Vex estimated a hand-crafted Candela at around $6,000, and German press coverage put it between 6,000 and 7,000 euros. The 2018 pedal version lists at $269.
Sources (9)
- Vibrophase, ZVEX Effects
- ZVex Candela Vibrophase, gearnews.com, 2016-02-24
- Z.Vex unveils world's first candle-powered effects pedal, the Candela Vibrophase, MusicRadar, 2016-02-24
- The Candela Vibrophase, ZVEX Effects, 2016-02-18
- Data Sheet and Technical Specifications, ZVEX Effects
- First Z.Vex Candela user demo on YouTube, gearnews.com, 2016-08-19
- The ZVex Vibrophase Is Now Portable (and Safe), Delicious Audio, 2018-05-18
- ZVEX Effects Presents Candela Vibrophase, Guitar Interactive Magazine, 2016-02-24
- Get psyched for ZVEX’s new psychedelic pedal, Guitar.com, 2018-05-16
