The Teenage Engineering OP-1 has been the blueprint for the portable hardware all-in-one DAW since its release in 2011. While it has been superseded to some extend by its new field version - the price tag may put it out of reach for some. The LMN-3 is a new open-source projects which appears to be heavily influenced by the OP-1 and available with all the details specs and a BOM to build your own.
A further video on updates and extensions has also been released:
It features a sampler, synth, effects, looping, a mixer, sequencer, plugins, and much more. Not only does it look the part, it sounds fantastic and puts it up there with the excellent Dirtywave M8 as another highly versatile alternative to the OP-1. A build guide is available here and you can find out more about the project on GitHub.
More info here: https://github.com/FundamentalFrequency
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