Originally Posted by kramer5150
It was not uncommon for production manufacture to OEM supply to others, who in turn re-branded and sold as their own. So it was a web of cross-path supply chains.
I have AEG branded tubes that are Telefunken
Telefunken was a subsidiary of AEG; so, this was in-house.
and some more that are Amperex-holland.
The correct name for that is Philips. For the Dutch production, Amperex was just a brand applied to the US market.
There was also military supply / surplus and others who simply did not brand anything at all on the tube.
True. The UK military was not too interested in brand names on their valves.
Looking at your pics... they are not Mullard M8100, they are CV4010. Compatible tubes YES... but not exactly the same thing. CV was sold to commercial consumer market while the M8100 was a military supplied part.
You've got those two mixed up. CVs are the British Service codes.
"The CV4010 is the UK Government code for the commercial M8100 which in turn is Mullard's special quality version of the EF95." (http://www.r-type.org/exhib/aaa0901.htm)
I do not know for sure what the EXACT / construction and spec differences are between the two.
None. Same thing. Really. Not all M8100/CV4010s were made in the same factory over the years, though. Steelsix's were made at Mitcham. The one shown at the address above was made at Whyteleafe.