Quote:
Originally Posted by Maarten
First thing I thought of as well. Prtty sure it just means 'mains'.
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Agreed that is the logical interpretation here. I was unaware of that meaning before now, but I had previously seen “secteur” as a short form of “secteur industriel”.
Quote:
Originally Posted by Maarten
Something else: I don't think EAA91 and EB91 were the same valve, they had a slightly different envelope, but I don't know whether that's significant (industrial range, copy of US valve, etc).
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For most purposes the EAA91, EB91 and 6AL5 (and the D77 and 6D2) seem to have been viewed as being interchangeable, despite their physical differences. Perhaps there were some subtleties that required both the EAA91 and EB91 versions. Maybe the EB91 was too tall to fit some compact equipment that had been designed around the 6AL5, so an exact physical copy of the latter was required in the European series, hence the EAA91. It would appear that the EB91 preceded the EAA91. The EB91 followed the EB41, but then the design of the latter may have been influenced by the 6AL5. There might be a complex story in there that has yet to surface.
Cheers,