At SynthFest France 2025, vintage synth expert Olivier Grall showcased the RSF Synthesizers: here is a tour with many details on this special company.
Every year, SynthFest France hosts a vintage synthesizer corner alongside the traditional exhibition of new synths and DIY projects. This year, Yves Usson (Arturia Minibrute developer), Alexis Faucomprez (Musical Saw (video linked), and Olivier Grall participated.
Oliver Grall has an actual vintage synth museum and dedicates his exhibition each SFF edition to a different brand. In 2023, he showcased Yamaha synths, following Korg’s appearance the previous year. This edition, he dedicated his booth to the iconic French band RSF.
RSF Synthesizers
RSF was a French Synthesizer company founded by Ruben and Serge Fernandez. During their active time, the RSF developers released numerous analog synthesizers that are now legendary yet rare, including the Kobol system, Polykobol, and the super rare RSF Modular, to name a few.
There isn’t much “behind-the-scenes” information available about RSF synthesizers. Much information is based on estimations, such as production numbers, and what is official comes from Olivier Grall, the most respected RSF expert, as he’s in contact with the developers.
This is also the reason why Behringer brought Olivier Grall on board to develop the Kobol clone/replica. Among other things, Olivier was responsible for aligning the original with the clone and providing Behringer with feedback on what could be improved. This is still the only source today if you want an RSF-style synth without going the expensive vintage route.
Olivier brought a wide range of RSF synthesizers to SynthFest France 2025. I was almost thrown off my feet because I’d never seen so many working RSF synthesizers in one place.
On display were two complete Kobol systems, featuring all expanders, including the Preset Expander, the Kobol keyboard, the super-rare RSF Modular, the equally rare Polyclavier, and more.
I took advantage of this unique opportunity to interview him about his RSF synthesizers and the history behind the company, etc. I also wanted to obtain answers to questions that have been circulating online.
As an additional note: these vintage synthesizers belong to his studio, which he offers to outsiders for recording sounds, tracks, and other purposes. He has already offered his services to several well-known companies, including Arturia and UVI, which have already recorded sample libraries.
More information here: OG Studio
Behringer Kobol & Xils Lab PolyKobol III are available at my partners
Sweet racks! Surprised I didn’t hear a mention of the famed PolyKobol 2? I’ve only seen a few videos on YouTube but it seemed like a probable holy grail beast.