by EWBrown » Wed Jun 29, 2011 8:46 pm
Back in the 1950s and 1960s, the US Dollar was strong, and most European currency was relatively "weak", and the Mullards, Telefunkens and Amperex tubes were generally considered as being the "cheap imports" at the time.
These tubes were often supplied with kits at the time, as they cost less than their US counterparts. Little did they know....
FWIW, some of the Radio Shack "Lifetime" 12AX7s were Telefunkens, they have the little tell-tale "diamond" embossed on the base.
Radio Shack just chose replacement or equivalent tubes which cost them the least, and the same tube type may have more than one country of origin, from year to year.
/ed B
Real Radios Glow in the Dark