Michigan Synth Works unveils LRB-303 DIY kit and OS-303 Arduino-compatible 303 processor

Michigan Synth Works opened the door to a new DIY take on the TB-303 with two simultaneous releases: the LRB-303 DIY 303 kit and an OS-303 open-source processor. The LRB-303 kit is listed on the Michigan Synth Works product page at a regular price of $499.00 and the company’s messaging stresses an all surface-mount design and carefully chosen parts meant to match the original 303 circuitry.

The kit ships as a near-complete package. Michigan Synth Works lists an SMD populated LRB-303 Mainboard and SMD populated LRB-303 Switchboard, Alps Tact switches, Alps Rotary switches, LEDs, standoffs, a switched DIN socket, and mainboard through-hole parts spelled out as 8 Pots, 2 Brackets, Slide Switch, Audio, DC, CV Jacks. The box also includes precut and tinned ribbon cables (4 pieces), precut interconnect wires, and four dust covers. Crucially for MIDI setups, the kit explicitly includes an OS-303 Processor with MIDI harness. The product page also notes what is not included: a knob set and a case kit, the latter offered separately through a partnership.

Michigan Synth Works’ social copy framed the design as intentionally approachable: “So how about a new 303 kit? Presenting the LRB-303 DIY 303 kit! This is an all surface-mount device with parts meticulously chosen to match the original.” The company added, “No rare parts to hunt down, no fakes to deal with, no endless sourcing.” All surface-mount parts are machine assembled so that “there’s very little actual soldering to do,” and coverage of the launch repeated the claim that “you can build the kit in an hour or two,” positioning the LRB-303 for electronics newcomers as well as seasoned builders.

Cases for the LRB-303 are being supplied by JLC3dp and will be available in multiple colors; Michigan Synth Works and coverage around the announcement cite five colors overall, including the original silver plus blue and red. Matrixsynth’s March 3, 2026 post highlighted blue or silver variants specifically, while the product page and Gearnews material give the broader five-color note. The product page requests customers “Please allow 7-10 days for order fulfillment,” though some outlets described the kit as “not available yet” or said it “will be available later this month,” reflecting the teaser-and-preorder moment around the March 3 announcement.

The OS-303 is being released as an Arduino-compatible, open-source 303 processor; Michigan Synth Works and coverage point to an MIT-licensed repository with code on GitHub and a project Discord channel. CDM noted, “The chip already has a project page and an MIT-licensed repository, plus a Discord channel.” The OS-303 is listed as a standalone item at $40, and the inclusion of the processor in the LRB-303 kit brings that open hardware directly into the build. Coverage observers also flagged a repair angle, citing that “That u650 processor was used in the TB-303, TR-606, and TR-808. This has implications for repair of the aging Roland hardware, too.”

With a $499 kit price, a $40 standalone processor, SMD-populated boards, JLC3dp-supplied cases, and an MIT-licensed GitHub repo plus Discord, Michigan Synth Works has combined a ready-to-build LRB-303 with an open, hackable OS-303 platform. The releases fold accessibility, community tooling, and an eye toward repairability into a package that aims to appeal to builders who want TB-303 style circuits without hunting vintage parts.