Adding some designer/manufacturers from the (distant) past to my previous post, which only addressed those who are presently active:
-- Saul Marantz & Sid Smith, at you know which company.
-- H. H. Scott & Daniel von Recklinghausen (at the original H. H. Scott company). I believe, btw, that it was Daniel von Recklinghausen who first said "If it measures good and sounds bad, it is bad. If it sounds good and measures bad, you’ve measured the wrong thing."
-- Lincoln Walsh (Brook Electronics, which manufactured high quality amplifiers using 2A3 directly heated triode power tubes in the late 1940s and early 1950s; also the creator of the Walsh driver later used in Ohm speakers).
-- E. H. Scott (no relation to H. H.), who manufactured high quality multi-chassis "radios" mainly in the 1930s (many using 2A3 and 45 power tubes), which can be considered to be precursors of modern hifi systems.
-- McMurdo Silver, a competitor of E. H. Scott; same description applies.
Best regards,
-- Al