I have a one-off pair of Altec Super Big Reds (604E2s) in furniture cabinets (oak) that are tri-amped with a one-off electronic crossover and one-off passive eq units to go between the amp and the horn drivers.
I drive them with vintage Marantz equipment including two 170DCs for the four woofers and an 1180DC to serve as the preamp and power amp the horn drivers. I bought these from a recording studio that went out of business. I also have the matching 2130 tuner with the scope.
I was trying to track down their origin, but Doug Sax passed away a couple years prior to when I got them.
When we had a meeting here of the JBL people, everyone agreed that these were the best 604s they had ever heard. If you were on the west coast, you would be welcome to come by and hear these.
BTW, I really don't listen to these much and they could be had, but only as a complete set. All amps were recently serviced. Would be he-- to ship those 15.5 cu ft, exterior volume, cabinets from the left coast!