Founded by Steve Harmon in Seattle in late 2009, Synthrotek is a DIY audio electronics company based in Moscow, Idaho. The company began when Harmon started hand-etching circuit boards to build small synthesizers and realized other hobbyists would appreciate accessible, affordable kits. Their first completed project was an Atari Punk Console kit, and the company has since grown into a comprehensive source for Eurorack modules, lo-fi synthesizers, guitar pedals, powered cases, and electronic components — all offered as both fully assembled units and DIY kits.

Synthrotek's product line spans over 40 Eurorack modules including the DIRT Filter (a characterful low-pass filter with a unique Bias control), the Arcadian Rhythms (an arcade-button manual gate module), the ECHO delay module, and the Sequence 8 analog step sequencer. Their lo-fi synthesizer kits include the 4093 Chaos NAND Synth, the Nandamonium, and the Optical Theremin, while their guitar pedal offerings feature classic circuit clones like the Arbiter Fuzz Face, the Mean Screamer, and the Ratatak. A notable part of their catalog is the MST (Mattson-Synthrotek) line, a collaboration with synth designer George Mattson of Mattson Mini Modular, which includes higher-end modules such as the MST MIDI to CV Converter, MST Dual 2164 VCA, and MST VC LFO.

All Synthrotek products are hand-assembled in the United States. The company emphasizes accessibility and education, providing detailed assembly instructions and schematics for their kits to empower electronic music enthusiasts and hobbyists to build their own gear.

Synthrotek has 17 products cataloged on Equipboard, including Modular Synthesizers, Sound Modules, and Delay Effects Pedals. Their gear is featured by 2 artists, with the strongest followings in Electronic. Notable users include Richard Devine and risaripa.