Telefunken in Disguise?


A highly rated Audiogoner sold me what are supposed to be a pair of Telefunken 12au7 smooth plate tubes. What actually arrived were tubes labeled "Mazda BelVu 12au7  ECC82." They do have what appears to be a diamond engraved on bottoms, although it is hard to see. He insists these really are Telefunken - made 12au7 smooth plates. I do not know enough to accept or not. I cannot find anything on-line confirming his representations.

What say the the tube experts?

Neal
nglazer
On counterfeit you can make fortune especially on ones that have no compromise in performance to the original. I once had Dr. Dre beats studio purchased for $12 sounded and looked exactly the same as $250 ones. When Alibaba wasn't US owned company, it was HEAVEN -- no labor needed -- just buy and sell.
Very often I noted counterfeit is just the same product, but manufactured voiding customs, taxes, commercials... another words just product without too much of third parties. Every dark side indeed has bright one as well.

The Tubemonger Library, a great resource for identifying tubes has a couple of pictures of Telefunken 12AU7s labelled Mazda Belvu here:

http://www.tubemongerlib.com/gallery2/v/12AU7/Telefunken+12AU7A+ECC82+Smooth+Plate+Diamond+Bottom+Mazda+Belvu+Label+1+-+Western+Germany.jpg.html

If yours have the diamond on the bottom and look like the ones in the photos, I'd say they're Telefunkens. 

ebm, I too have a few "Telefunken" tubes that sound bad. However, of the 16 best 6922's I have ever heard, 16 are Telefunken. That includes US Amperex (including pinch waist), Dutch Amperex, Siemens, etc.