I have John's first Sole sub-chassis prototype (back when it was alu sheets glued to a wood center) on my LP12, he did me a great deal & it was the best upgrade I ever did to it. Also have one of his charcoal cork Plattamats and even tried an early pair of InSoles (but didn't get on with them and swapped back - given all the good recent feedback, I should have tried a newer set).
He was one of the first to kick off sub-chassis upgrades - started as a DIY project and then turned it into a business...albeit not an easy one I think. Hats off to him.
My condolences to his family too.