Thanks guys this is exactly the response I was hoping. Thanks to "I like Music" for the visuals. I'm hoping to discover an amp someday in an old venue somewhere.
Long story, tried to recall as much as I could -
I pulled the gear out of a drive-in near me July 1992. I can date it that exactly too! Actually got the gear out while the bulldozer was spooling up to demo the projection booth. I literally was driving by (after seeing regular demo of a week or so) and saw the demo crew on site. I drove up to the booth and asked if I could look inside then saw it was still stuffed with electronics. Then I asked if I could have the gear and they said to be quick. I was in my wife's car and did not have my tools. The only thing in the car was a combo tool adjustable wrench w/ screwdrivers, can opener, & file that folded out of the handle like knife blades. Absolutely miserable to use. It was also mid-July with equator level humidity and I got stung several times by wasps. However, I got all the tube gear!
There were 3 systems in there that likely coincided with first system, upgrade to 2nd screen, and final switchover to solid-state. All the speaker poles had transformers in the heads so it was clearly a constant voltage system. What I believe the original sound system used were a pair of Simplex AM-1001 amps. They were still in place but not wired up. I wish I'd been able to get the rack they were in. The amps slid out like drawers and flipped over to service them. It was clear that this was the original rack they were installed in. The bolts that secured them in and these took the longest to get out.
The second screen system used a pair of Simplex AM-1026 booster amps. A pair of Century 5W-117 (I think) drove the AM-1026's. All this was on steel industrial stye shelves, not a rack. The amps were just sitting in place and easy to get out. The were also no longer wired up but left in place. Although the AM-1001 needed extensive repairs to get running again, the AM-1026s worked without issue which was pretty amazing. The Century amps however did not. The projectors were long gone and I don't know what the preamp drives were from them to the various amps.
Lastly was the final change to solid-state. There were a pair of Bogen or Dukane (can't recall) mixer amps which I left. They were rusty right through the paint even though the room itself was pretty dry. I'd guess the solid-state gear was used until the early-mid 80s. Sometime after that the drive-in switched over to wireless FM transmission. (That gear was long gone in the projection booth as were all the speakers from the poles.) I know it was wireless FM in summer 1985 as myself and a bunch of coworkers went there after work and saw
Lifeforce. A few years later I married one of my coworkers and we still are. As an aside which I will only admit here, I was on my way to meet my wife for Lamaze class. I made it to the class sweaty but just in time, my wife had no inkling what I'd been up to, and my son was born a couple months later.....
All the gear except the Century amps are long gone. The AM-1001s were absolute **** for full-range use when I got them running. They were clearly designed only for the bandwidth of the 4" pole speakers. The AM-1026s were great though. Although it was tough to get over that you needed an amp to run them, they sounded fine off a Scott 299. I set up in my listening room for a bit before they went on down the road. The Century amps used the same iron as the Altec A127, one of the best 6L6 amps ever IMO. One of them had a blown output transformer (TL-217) but I got another off a roached Altec 323 amp. I like to build a set of pseudo A127s from this pile.
Simplex AM-1001
Simplex AM-1026
