The Mastro Valvola LFO is a tremolo pedal from Mastro Valvola, an Italian manufacturer. It uses an analog optical tremolo circuit, the same approach at the heart of classic amp tremolo, but a digital brain controls the device, which is what makes its 16 waveforms, tap tempo and note divisions possible. Premier Guitar's reviewer described it as taking "an optical tremolo circuit and applies some clever tweaks and modern functionality"1.
The controls: speed, tap tempo, symmetry and 16 waveforms
The LFO offers 16 different waveforms, many of which can be pushed well beyond typical tremolo territory into bit-crushed and chaotic shapes. Named waveforms include "Quad Pulse," "Tri Step" and, for the chaos-inclined, "Random Slopes"12. You pick a waveform, then dial in the LFO speed (or tap tempo it out) and depth2.
Each waveform can be radically reshaped by a symmetry knob, which lets you tailor the interaction between the tremolo waveform and your signal in very specific and often radical ways. A toggle offering three different note divisions adds what Premier Guitar called "even more (and more demented) wave shaping power"1.
| Control | What it does |
|---|---|
| Speed | Sets the LFO speed, or set it with tap tempo2 |
| Tap tempo | Syncs the speed to your playing; described as invaluable by Premier Guitar1 |
| Symmetry | Reshapes each waveform and how it interacts with your signal1 |
| Note division toggle | Three different note divisions for further wave shaping1 |
| Volume | Extra output to offset volume loss or push an amp's front end1 |
The volume knob is a practical bonus: it has enough extra power to compensate for perceived volume loss, boost the front end of an amp, or turn the LFO into a much bigger sounding effect when activated1.
An analog optical tremolo with a digital brain
At the heart of the circuit lies an opto-isolator, the component an optical tremolo uses to vary the signal level, with the digital brain managing it2. That split is the pedal's defining design: the audio path stays analog and optical, while the digital side generates the 16 waveforms and timing features. Premier Guitar's reviewer put it plainly: "Although an analog optical tremolo circuit is its ticking heart, a digital brain controls this device"1.
History: inspired by sixties tube amp tremolo
Tremolo was commonly found built into many '60s tube amps, such as Fender's Vibrolux and the Vox AC303. It was then built into many vintage amps, with wildly different circuits depending on the brand, before being displaced by phaser and chorus in the 70s and 80s, and returning by the end of the nineties4. The LFO is inspired by the tremolos on '60s-era tube amps2. Mastro Valvola unveiled the pedal in 2018, and Guitar.com reported it lists for EUR 2152.
What reviewers said
Premier Guitar's reviewer found the pedal's fundamental tones are classic optical tremolo: organic, warm, and satisfying at subtle and extreme settings. The verdict listed among the pros: "Great sounds from wild to mild. Extremely versatile. Feature-packed."1
The enclosure was described as bulletproof, with a distinctive heft and solidity, in a red, white, and raw aluminum color scheme with asymmetrical control placement. Practical design touches include top-mounted jacks, appreciated by space-conscious players1.
"Great sounds from wild to mild. Extremely versatile. Feature-packed."
There is no preset saving on the LFO. Guitar.com noted in 2018: "Unfortunately, you can't save presets on this."2
For more on this pedal and other options in the effect family, see Tremolo Pedals.
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Questions
Can the Mastro Valvola LFO save presets?
No. Guitar.com noted in its 2018 coverage that you cannot save presets on the LFO. Settings are dialed in by hand on the front panel, so players who need recallable sounds have to note their knob positions or manage them from the board.
Does the Mastro Valvola LFO have tap tempo?
Yes. The LFO has a tap-tempo feature that Premier Guitar's reviewer described as invaluable, and speed can also be set with the speed knob. A toggle offers three different note divisions that multiply the wave-shaping possibilities of the tap tempo.
How much does the Mastro Valvola LFO Optical Tremolo cost?
Premier Guitar's 2021 review listed a street price of $249 USD. When the pedal was announced in 2018, Guitar.com reported a list price of EUR 215.
Can the LFO's volume knob boost an amp?
Yes. Premier Guitar's reviewer highlighted a volume knob with enough extra power to compensate for perceived volume loss, boost the front end of an amp, and turn the LFO into a much bigger sounding effect when activated.
Where are the jacks on the Mastro Valvola LFO?
The jacks are top-mounted. Premier Guitar's reviewer called this an example of the pedal's practical design, appreciated by space-conscious players, since top jacks let a pedal sit closer to its neighbors on a crowded pedalboard.
Sources (4)
- Mastro Valvola LFO Optical Tremolo Review, Premier Guitar, 2018-09-18
- Go tremolo wild with Mastro Valvola's new pedal, Guitar.com, 2018-04-18
- Best tremolo pedals for guitar: Shake up your tone, MusicRadar, 2019-10-23
- optical tremolo, Anasounds, 2025-08-27
