"Harvey came to be associated with those mods via his close connection to NYAL". I'll say it was close---Harvey owned NYAL! In his search for the best amp for his Quad loudspeakers, Harvey learned of Julius Futterman and his revolutionary and radical OTL circuit. Harvey discovered Julius was living right there in Brooklyn, and befriended him, becoming his best friend and confidant.
Harvey knew circuit design, and the two of them started working together on solving some of the Futterman OTL circuit's problems (it was, amongst other things, rather unstable, exhibiting a lot of parasitic oscillation). When Julius' deteriorating health made it clear he would soon die, he sold the rights to the Futterman name and the OTL design to Harvey, who subsequently started NYAL to manufacture and market tube electronics. It was only then that George Kaye was hired by Harvey, who worked with Harvey on continuing the improvements to the Futterman circuit. George was largely responsible for the design of the NYAL Moscode products, which incorporated mosfets and tubes in a hybrid design, Harveys way of bringing tubes to the masses.