Hiero Effects is a Russian boutique pedal builder specializing in handmade fuzz and dirt circuits for guitar and bass. The shop operates without a traditional web store, taking orders through Instagram and email and listing finished units on Reverb, where the pedals are typically tagged as Russian boutique builds.

The lineup leans heavily toward fuzz, with offerings such as the Heretic Fuzz, a silicon circuit that blends Big Muff, Fuzz Face, and Tone Bender voicings into a single box; the Explicit Fuzz, another silicon-based original design; the B.E.A.D. Fuzz, a bass-friendly octave fuzz inspired by the Maestro Brassmaster lineage and the Malekko B:assmaster and Iron Ether Oxide; and the Phatoum Fuzz, a take on the Boss FZ-2 Hyper Fuzz with separate bass and treble EQ and a three-mode switch covering FZ-1, FZ-2, and boost voicings.

The brand has gained visibility in doom and stoner circles through its Churchburner, a signature variant of the Phatoum built for Thomas V. Jäger of Monolord, who has spoken publicly about using the pedal as his primary fuzz.

Hiero Effects has 2 products cataloged on Equipboard, including Fuzz Effects Pedals.