The ESS speaker I would still like to find is the Super Quad. It used the original Quad ESL for the midrange, with the same transmissionline-loaded Kef B-139 woofer and RTR tweeters as did the Transtatic. Not many were made---it retailed for $2000 in the early 70's, same as the Infinity Servo-Static, to which it was intended to provide competition.
Ess Company
I worked at Ess in Sacramento California which was located at the time on Oates Drive just off of Bradshaw Road. There was also the "Vinyl Plant" located off of Folsom Blvd. Memory not as good now but I worked there for approximately 2 1/2 to 3 years from 1979 to approximately 1982. I started off in the "wood shop" routing holes for the speaker fronts. Very soon after the warehouse had an opening. Worked in the warehouse for most of my time there. Great job! I was saddened when we were told the plant was shutting down. They gave us severance pay for I believe was 2 months. Also made several runs to an Oakland Ca. machine shop for some type of speaker parts. Still have many fond memories of ESS Sacramento.