Michigan Synth Works LRB-303 Is an Easy 303 Kit for Less Than $500
Get your DIY acid on with Michigan Synth Works’ new LRB-303, an easy TB-303 kit, plus OS-303, an open-source 303 processor. And they’re both very affordable.
Michigan Synth Works LRB-303: Happy 303 Day
Happy 303 Day to all who celebrate! It’s the most lysergic time of the year. To celebrate, Michigan Synth Works has dropped not one but two TB-303-related products – and they’re very exciting indeed.

The first is LRB-303, a DIY kit that recreates the Roland TB-303 experience for not much money.
“So how about a new 303 kit?” asks MSW on its Instagram. “Presenting the LRB-303 DIY 303 kit! This is an all surface-mount device with parts meticulously chosen to match the original.”
MSW explains that the surface-mount parts are machine-assembled, meaning there’s very little actual soldering to do. The company says that you can build the kit in an hour or two. This makes it a great kit for electronics newbies. “No rare parts to hunt down, no fakes to deal with, no endless sourcing,” MSW says. You’ll have to get the case and knobs on your own, though, as they’re sold separately.
What You Get
Here’s what you get:

- SMD populated LRB-303 Mainboard
- SMD populated LRB-303 Switchboard
- Alps Tact switches, LEDS, Standoffs
- Switched DIN Socket
- Mainboard Through hole parts (8 Pots, 2 Brackets, Slide Switch, Audio, DC, CV Jacks)
- Precut and Tinned Ribbon Cables (4 Pcs)
- Alps Rotary Switches
- Precut interconnect wires
- OS-303 Processor with MIDI harness
- Dust Covers (4 pcs)
The case is being supplied by JLC3dp and will be available in five colors, including the original silver plus blue and red.
OS-303 Processor
The heart of the LRB-303 kit is the new OS-303 processor. This is a drop-in replacement for the u650 processor used in the TB-303, TR-606, and TR-808, although only the TB-303 code is available now. (As Peter Kirn points out, this presents exciting possibilities for repair of original 303, 606, and 808 models too.)

This is “an open source, Arduino-compatible TB-303/u650 processor,” says MSW on Instagram. “This is a project I have started with the help of ace coder and fellow Michigander Phazerville to bring an open codebase for everyone to use/hack/modify to build processors for TB-303, TR-606, and TR-808.”
Pricing and Availability
The Michigan Synth Works LRB-303 DIY Kit is priced at $499 and includes everything you need except case and knobs. It’s not available yet, though. More details coming soon.
Likewise, the OS-303 is also not available but will be sold for $40. You can access the code at the GitHub here.
More Information
- Michigan Synth Works LRB-303 product page
- Michigan Synth Works OS-303 product page
- More about Michigan Synth Works
- More about synthesizers
- Buy synths at Thomann*
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