Just to set the record straight-er, Harvey was certainly a patron of Julius Futterman's, but Julius patented his OTL circuit in the very early 50s, probably before he ever heard of Harvey. Later on, Harvey and/or New York Audio Labs, the company NYAL, may or may not have paid Julius some money for the rights to sell their OTL amplifiers which used the Futterman output stage, but Harvey almost certainly had no part in collaborating with Futterman design amplifiers. NYAL had an excellent engineer named George Kaye on the staff. Mr. Kaye made some mods to the Futterman design that were said to improve bass performance and maybe the capacity to drive low impedance speakers. Harvey came to be associated with those mods via his close connection to NYAL. But the brains belonged to Julius in the first place and George Kaye at NYAL. This is more or less the story from where I sat. Harvey was a funny, clever, and certainly very smart guy who understood marketing, but I do not recall that he was a circuit designer in a primary way. Yes, he was the self-styled "Tube God".