In the end, this turned out to be a very educational and entertaining thread. It was like watching those old electronic theory films with Three Stooges clips occasionally spliced in for a distraction. I own a variant of the 811 (the 811HD) and have found that it can live up to expectations provided you don't expect much. They are cheaper but for a few dollars more, you can buy a good amplifier. If I had done my research years ago, I would have spent the extra money and bought the AL-80B.
I bought three 811's on eBay when I put them in the room lights blinked and the fuse blew, the filaments did not light. When I took them out and put the original tubes in everything was fine. When I examined the tubes, in two of them the filaments were floating around inside. The seller seems very responsible. Why did this happen? https://www.ebay.com/itm/QTY-3-THRE...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
If you bothered to read the ad you would have seen the guy was really careful in testing. I did get a refund. You are a smart guy, I would have expected a more intelligent answer. I stayed in Danbury in the 50s, near Clapboard Ridge where the high school now is.
811 tubes are just tubes you don't buy used. Makes no sense. At least not to me. As you said, I'm a smart guy, and that is my take on it. I have bought many used 8877 tubes but I doubt I would buy used 811 tubes. I KNOW you know where I am coming from on this. OK, so what was your Clapboard Ridge address? The school is about a mile or so from my house. I am on Ball Pond Road which is basically an extension of Clapboard Ridge but where Padanaram road comes in they change the name from Clapboard Ridge to Ball Pond Rd. It is all route #39 from EXIT 5. Things were different in the 50's. This house was built in 1985.