Interesting but I wonder. I have owned 3 NC 183D receivers and run them by plugging into the line socket for years and never had a failure. Yes they get hot and yes heat will hurt them, but if you replace out of spec components, tubes and be sure the ventilation is good then it should last. All the old design criteria was 115 volts +/- 10%. That would equal to +11.5 added to 115 so it should work ok. Don't block the vents and if something in the audio section or power supply doesn' short, the transformer should be ok. I always put a thread of RG 58 shield wire in the HV lead right where it comes out of the rectifier to prevent a short from ruining the transformer.
I have to agree with Jim, Although nice, a bucking transfoma, is it really necessary? ?
I run EVERYTHING right out of the wall socket. My line voltage varies from 115 to 125v, depending on the time of year. My stuff, especially the recievers will easily run sometimes for 12 or more hours at a clip. Yea, they get a little warm at times. but it helps bake the moisture out of everything. As long as you dont have leaky caps, to overload it, it shouldn't be a problem. I also have never had a power transformer failure in my low power stuff. Plate transformers in high powered stuff is another story.
Class-A P/P 6V6s do get brutally hot, and that is just the way it is. As long as the plates arent showing any color, they're prolly OK-Fine. I have gotten some nasty burns off of class-A audio outpoot tubes over the years.
When someone on here describes something as "getting hot" you really don't know what to think. Especially if they describe the voltages as being way off, you start to expect to find a problem..