Here’s a good way to start 2026: the folks at Surge Synth Team now have their free and open-source OB-Xf synth in beta status in nightlies, with 1.0 just around the corner. And that means this long-running project is just about ready for primetime, bringing a fully open instrument inspired by the 1979 Oberheim OB-X.
The incomparable Surge Synth Team, that source of open-source goodness, took over this project late last year, following previous work by discoDSP (and 2DaT before that). See BPB’s coverage from September. OB-Xf had some lingering bugs and unfinished bits, but it already sounded great at the time:
Having this kind of open project has major fringe benefits. When Khyam Allami and Counterpoint built the superb online tool Apotome, they were able to include Web versions of instruments, and OB-Xf is one of the best. That opened up explorations of tuning with a full-fledged synth, without having to install other software, expanding possibilities beyond what’s available in commercial software and in environments that might lack access to proprietary desktop tools. (See my interview with Khyam.)
It may not sound like a big deal, but the beta is a huge milestone — already after just a few months’ hard work. The developers report that this release is stable. Just be sure to read the notes:
This page contains a copy of OB-Xf built from the head of the repository. We consider this a beta build.
To install on your system, download the appropriate installer (dmg, exe, deb) and run it.
We also provide a ZIP archive for Windows and Linux, but when using these you are responsible for placing the assets from the assets.zip file to the right location on your system. If you take this route and get it wrong, run the standalone and it will show you where it attempted to look for assets.
We have a few items left to do between beta and a 1.0, including finishing MIDI learn UI/UX and resolving other bugs in the beta period, but the synth is stable now.
Today’s build has a few changes but notably adds MIDI Program Change support.
If you want to try the beta, the nightly build is where to go — and includes those installers for Mac, Windows, and Linux.
https://github.com/surge-synthesizer/OB-Xf/releases/tag/Nightly
I quickly fired up the January 2 build on macOS and — wow, it went without a hitch. (I think it was actually easier that installing a lot of proprietary software, cough.) There are two included themes, both the default (at top) and a vector-based theme that seems to be a bit more accessible (see screenshot below)), plus a bunch of presets and modern settings and menu system.
The project is GPLv3-licensed and hosted on GitHub, on the Surge account.
https://github.com/surge-synthesizer/OB-Xf
Note that this is not an officially Oberheim-authorized project, which is why you don’t see any mention of Tom or the Oberheim name or brand. For that, you want GForce’s excellent OB-X — I’ve talked to Tom about that, and he’s a fan. It’s on sale as I write this:
But that being said, it’s great to have both projects. It shows the staying power of Tom’s design work and its relevance nearly a half century later. (Uh… yes, since my birthday is not far from the OB-X, you know, good that things are lasting that period of time.)
And having a community-led effort to model the instrument also means a chance to share knowledge and make the tools available in other contexts — Surge have incorporated a lot of their work into Surge XT and its VCV Rack module companions, for a polysynth platform that’s grown like no other. It’s really a community synth. That has its own roots in history; before the rise of chips under blobs, engineers were able to peek into each other’s designs via service manuals and whatnot.
So I’m excited to see what this means — especially as it comes hot on the heels of the JE-8086 project for Roland. We’re at a great moment in open polysynths, and in a year that might not have a lot of other optimism, there’s something to be optimistic about.