Doesn’t Brimar stand for "British Made American Range" to enable the UK tube maker (it was part of ITT and got bought or renamed as STC if memory serves) to compete with the American tube configurations?
I'm also not sure Brimar manufactured all the tubes bearing their brand, even though they did have a a factory in the '30s. I have a very nice GEC U-52 rectifier branded Brimar- cost me less than the same tube with the GEC label on it. There are also some Brimars that have been relabelled more recently, using other brands that draw more money. There are a few web articles on this, and I'm sure any old tube hand or good vendor could tell you more. Apparently, the brand was recently revived, but I didn't really look deeply into the details.
I'm also not sure Brimar manufactured all the tubes bearing their brand, even though they did have a a factory in the '30s. I have a very nice GEC U-52 rectifier branded Brimar- cost me less than the same tube with the GEC label on it. There are also some Brimars that have been relabelled more recently, using other brands that draw more money. There are a few web articles on this, and I'm sure any old tube hand or good vendor could tell you more. Apparently, the brand was recently revived, but I didn't really look deeply into the details.