Can't single out one but they include several already mentioned - William Z. Johnson who was directly responsible for the rennissance of tube gear in the early 70's; Saul Marantz, one of the great pioneers of quality audio gear and certainly Nelson Pass for the best solid state designs I am aware of. I would also concur with some of the pioneers mentioned above.
Top Audio Designers Of All Time?
We have all had fun and world of info have spilled forth from Audiogon members. Lets give ourselves a round of applause. From me a sincere "Well Done" to all members that have participated. I have learned a great deal. In this thread,which may be a little esoteric for some,lets hear from members that support certain designers. After all if not for their dedication and genius,we would not have the topic or equipment. Ill start the thread for the inventor Thomas Alva Edison.For it was his revolution,that we now find ourselves here. In the more contemporary era I vote for Nelson Pass. His white paper on Cascode/Stasis toplogy was and is truly ground breaking. In my opinion since 1975,other designs are a variation on a theme of Pass.