Designers -who's been around the longest ?

Nelson a one trick pony? What a silly thing to say; he's only the most versatile amplifier designer in the history of hi-fi! He makes amplifiers employing dozens of different circuits, of all types and topologies.

As for Frank, the topic of this thread is who's been around the longest, not achieved the most legendary status.

Don’t forget about Frank Van Alstine, a designer talented enough to diagnose and fix the problems in early ARC designs (specifically the SP-3 pre-amp). As was just posted, Tim de Paravicini (EAR-Yoshino)---a master designer pretty much ignored here on Audiogon---recently left us, as did Roger Modjeski (Music Reference). Both huge losses to hi-fi.

John Curl’s name was mentioned by the OP, but only in terms of Parasound. Though Mark Levinson’s name is on that company’s products, the early Levinson models were all designed by Curl.

Before starting his own company, Nelson Pass worked at Electrostatic Sound Systems (ESS), doing speaker-related projects.