Mullards branded as Telefunkens???

[safetyman]

Does anyone know for a fact that Mullards did or did not manufacture for Telefunken? The reason for asking is coz I bought a pair of Telefunken 12AX7 which had no <> at the bottom, but the letterings were partially smeared off. The seller told me that these were Mullard made Telefunkens. Is this a fact???

 

[Colt45]

quite possible.

look for the acid etch code on it to see where it was made

 

[safetyman]

Maybe someone can help me with the codes. The markings on 1 tube is I63 and underneath that are the letters B8A4 and on the other tube is I63 and B7L3.

Could someone please assist or point me to any good resources for me to research the date codes?

 

[Colt45]

http://www.triodeel.com/images/philipstubecodes.pdf

 

[safetyman]

Colt, thanks. That is a very helpful guide.

 

[316a]

I63 and B7L3

Blackburn 1967 or 1977 , 'shortplate' version ECC83 with nickel grid posts

cheers

316a

 

[amperex]

Yep....

Yes, Mullard manu for Telefunken. No triangle at bottom of glass means not a true Telefunken W. German manufactured tube.

 

[safetyman]

Blackburn 1967 or 1977 , 'shortplate' version ECC83 with nickel grid posts

Thanks 316a and Amperex. I came to the above conclusion after researching the pdf file link that Colt gave. I am learning about tubes and how to decipher them. Very interesting.