1984 Matthias Grob builds the first prototype of Polysubbass, inspired by Peter Gregor – this is explained in the video below
1990 the first 100 Polysubbass are produced and sold with the Avalon guitars
2005 Rolf Spuler organizes the production of the SMD (small) version of the same circuit to build into the Paradis guitars. for simplicity, its called Polybass from now on.
2014 Rolf Spuler dies and Matthias decides to make the sound available to other guitars
2015 Tom Maier discovers that its not very difficult to replace one of the boards of the RMC Polydrive II (which is also used in the Godin Multiac) by a board with the Polybass. Philipp Scheidegger starts the design, with a brilliant preamp he has been working on for years and a complete rework of the Polybass circuit. problems are much bigger than expected and the board is made flexible to serve for other instruments, thats why it takes two years to finsh…
here the oldest page on the inventors site
here some more info on the paradis site
and here a recent video of the inventor telling the story: