It isn't so much that the designers purposefully try to burn the EL84's up, it is that 50-60 years ago the circuits of interest that used them were copied and pasted so many times in subsequent designs without addressing the voltage issues. If you have a power transformer designed to vintage specs, it will produce higher voltages today than it would have 50-60 years ago. Wall voltages in that era were closer to 110v. Add another 10-12 volts to the wall and the transformer will produce an extra 20-60 volts depending on the transformer. It isn't that AC30's were grossly destructive to EL84's in the '60s, it is that they biased them to near class A operation with a power supply that was running them at near their limit to begin with. Modern reproduction PTs just never really dealt with the voltage increase from the wall. So now we end up with modern designs that simply run EL84's to within an inch of their life. It's all the copying and pasting of old designs. There is gross negligence and there is simply no other option. I am not able to just pay to have a custom transformer made to my spec. So I have to work with what I can find. Other companies have a goal in mind and throw caution to the wind in order to get to that goal.
