The Orange and Green amps were made in the UK in the early 1970s (and later, and maybe earlier, I don't know the history) that featured odd graphics and stiff trnasformers. They used EL34s and 500+ volts. The 50 and 100 watt versions used the same transformers so the 50 watters were quite stiff. They used a simple split load phase invertor which by it's nature is unblalnced so they broke up easier then a Hiwatt but otherwise they were loud & hard. Their cabs were build almost exactly like the Hiwatt stuff. They had thick, rugged chassis. I had an OR80 back when I had a collection of amps. Quite the Thor's Hammer. They are being reproduced these days.
Edit: I found this history of Orange on line:
Liberty has never come from the government.
Liberty has always come from the subjects of it.
The history of liberty is a history of resistance.
The history of liberty is a history of the limitation of governmental power, not the increase of it.
-- Woodrow Wilson