Land Devices HP-2

The Land Devices HP-2 is a distortion pedal that sits between distortion and fuzz, built as a modern reproduction of the Interfax Harmonic Percolator HP-1, one of the rarest vintage effects around. Land Devices describes it plainly: "It's raw, gritty and chaotic. From subtle harmonic saturation to full-blown havoc, the HP-2 brings texture, tension, and a touch of madness to any signal."¹

It was Land Devices' first release, the HP-2 Distortion, and it pairs silicon and germanium transistors in a circuit that Delicious Audio says "can go from mild overdrive to face melting fuzz," with what the maker calls rich even-order distortion that is fat and warm². Both the HP-2 Percolator and the green "Percolator in Scream" finish are listed as sold out on Land Devices' product pages as of October 2026³¹.

The controls: H, B and the clipping rocker

The HP-2 keeps the control set of the original Percolator: two knobs and a switch. Land Devices describes them as follows³:

The rocker is the pedal's clipping selection. Guitar Pedal X calls the two positions "70's / Absolute Destruction" and says "the magic here really is its dual Clipping selection"⁶. Delicious Audio describes the same switch as choosing between the stock tone and a louder but less compressed one, with switch left giving the original circuit and switch right giving "doom"². Pedal of the Day's review characterizes the second mode as having higher output and a fatter, more modern type of tone⁸.

One behavior worth knowing before you plug in: Land Devices states that turning either knob fully counterclockwise kills your signal entirely. "Turn either knob fully counterclockwise, and your signal disappears into the void."³ Because H is input gain and B is output level, either one at zero silences the pedal, which is not how a typical tone-and-level distortion behaves.

Based on the Interfax Harmonic Percolator

The HP-2 reproduces the Interfax Harmonic Percolator HP-1, a two-transistor fuzz created by a small Milwaukee company in the 1970s⁹. The original paired a PNP germanium transistor with an NPN silicon transistor, which let it run in a standard negative-ground configuration, and it used clipping diodes, unlike most germanium fuzzes¹⁰. Guitar Pedal X notes the original circuit featured 2N404 germanium and 2N3565 silicon transistors, with a slider for "Harmonics," or input gain⁶.

The original is extremely rare and highly sought-after, and Aion FX reports that the transistors and some components were gooped or obscured in the original, which kept the circuit's details hidden for years¹⁰. Pedal of the Day calls the HP-1 "still a bit of an under-the-radar effect," part distortion, part fuzz, and surrounded by legend and myth⁸¹¹. Jack Orman's technical analysis at AMZ identifies the Harmonic Percolator as another commercial example of PNP transistors operated off a positive supply¹².

Land Devices put the HP-2 together as a modern reproduction, and JHS Pedals' history of the company quotes the maker on the design's look: the green version wears an olive drab finish with utilitarian, military-inspired knobs, colors and graphics, and a white limited edition version also exists⁴.

Other makers have built their own takes on the same circuit, including the Bowman Audio Endeavors Harmonic Percolator, which Pedal of the Day reports uses the same NOS NPN and PNP transistors as the vintage models along with a pair of NOS germanium diodes¹³.

What reviewers said

Published reviewers have been consistently positive. Guitar Pedal X wrote in 2024 that the HP-2 "has been incredibly well-received over the years - and for which every batch sells out super quick," adding that most players who try it rate and love it overall⁶. Pedal of the Day's 2018 review found that "the silicon and germanium transistors give off rich layers of sound that add presence and power to any rig or setup"⁸. At Guitar.com, Richard Purvis called it "another wonderfully impolite fuzz hiding inside a cleanly asymmetrical enclosure"⁷.

The pattern the press describes, batches that sell out quickly and a reputation that has held up since the pedal's introduction, is one reviewers keep returning to. Guitar Pedal X's 2024 write-up noted that every batch sells out super quick and that the pedal has been incredibly well-received over the years⁶, a view that matches the reception described across the other published reviews above.

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