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THIS TUBE HAS A DIFFERENT PINOUT and CANNOT BE USED IN 6BQ5/EL84 SOCKETS UNLESS YOU HAVE VERIFIED IT WILL WORK!These have gray plates and usually have a black graphite type coating on the inside of the glass which is to minimize electrical radiation.Any tube produced in the Telefunken factory should have a "diamond" molded into the glass in the base of the tube inside the circle of pins.If you don't see this diamond, then the tube wasn't produced by Telefunken. These are true Telefunken tubes as they have the characteristic diamond in the base.For that reason, allot of Telefunken tubes are devoid of most of their writing.These fakes have very nice writing and the printing will not rub off with your fingers or water.Amperex tubes were originally produced in Holland (The Netherlands) and are very high quality tubes. Some of them say "Made in Holland" and in fact are Japanese.
It has also come to my attention that there are some perfect "fake" copies produced in China which are difficult to tell from the genuine ones.
So if the tubes you see have really indelible printing, suspect that they are fakes.