Mastro Valvola — Italian for "Valve Master" — is a boutique effects pedal company founded by Luca Romanelli in 2008 and based in Tuscany, Italy. Romanelli, an amplifier specialist with deep expertise in vacuum tube circuitry, launched the brand with the Smog transparent overdrive and expanded the lineup into a full range of gain, modulation, and time-based effects. Every pedal is designed, assembled, and finished entirely in-house by a small team, from circuit board layout and component mounting to the distinctive graphic artwork printed on each enclosure.

The product line spans overdrive (Smog), fuzz (Love Buzz hybrid fuzz, OFF1 octave-fuzz-filter), compression (Millibar optical compressor), tremolo (LFO optical tremolo with 16 waveforms), delay (LEM Lysergic Emotions Module multi-head delay, TimeLab multi-delay), reverb (Area multi-reverb), and preamp/distortion (Tempesta lead channel). Many of the designs blend analog signal paths with digital control, and most are voiced to work equally well on guitar, bass, and keyboards. The LFO optical tremolo is among the brand's best-known and most widely praised pedals, while the LEM — with its eight ambiance modes, pitch-shifting, and bit-crushed trails — earned the company a reputation for creative, experimental delay textures.

Sometimes called "the Strymon of Italy," Mastro Valvola occupies a niche in the high-end boutique pedal market, combining Italian craftsmanship with versatile, feature-rich designs that appeal to players seeking tonal variety in a compact format.

Mastro Valvola has 4 products cataloged on Equipboard, including Delay Effects Pedals, Tremolo Effects Pedals, and Fuzz Effects Pedals. Their gear is featured by 1 artist, with the strongest followings in Rock. Notable users include Pete Thorn.