Hello! I recently ordered some Telefunken EL156 tubes from a supposedly reputable dealer, and received these unmarked 10-pin (y10a) tubes. They apparently are EL156’s, and to my knowledge the Chinese versions all have an octal sockets.. but I’m not convinced they are Telefunken or Siemens as the dealer claims. I’m hoping someone here can help me identify them. I would have taken more pictures, but there really isn’t much to see. There are no identifying marks whatsoever.
Telefunken produced EL156 valves for a few years and they all look like your photo. I know that my valve supplier will fit many different bases to satisfy my requirements; 5U4 in a four pin base etc.
Maybe the Chinesium valve manufacturers don't want to infringe copyright, (that'll be a first).
Maybe the Chinesium valve manufacturers don't want to infringe copyright, (that'll be a first).
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Thanks for your reply! Am I understanding you correctly that in your opinion these are Chinese tubes?
All original EL156's with 8 of 10 pin bases were produced by Telefunken, including those labelled Siemens. And yes, as JonSnell yet said, yours' look original, including those six holes in the plate fins with each three bits bent upward and downward. I hope you understand what I mean.
Chinese copies are octal based with the same unfortunate EL34 pinout (plate pin 3 next to heater pin 2). Telefunken EL156's have their plate brought out at pin 5 with a missing pin 4, followed by heater pin 3. This allows far more safe operation at 800 Vdc.
Best regards!
Chinese copies are octal based with the same unfortunate EL34 pinout (plate pin 3 next to heater pin 2). Telefunken EL156's have their plate brought out at pin 5 with a missing pin 4, followed by heater pin 3. This allows far more safe operation at 800 Vdc.
Best regards!
My best surprise was to see they both measure identically at DC with the datasheet within 5% error if i recall right. 5 years ago, a friend of mine, a 65 years old engineer 😉 also made the calculations for the 15 watts single ended transformers for them, but I never found the time and motivation to wind them.Just realized there's some magic about the number "5" ... I also needed to buy some 0.2 or 0.22 mm enammeled wire for that too and you can only buy it in high quantities here which is a bit expensive.Plus the original sockets...i miss them too.Thinking of the two pages of very complicated calculations my old friend did for me, i should probably make the transformers as i feel somewhat guilty.
Thank you all for your replies, especially Kay Piranha. The bent (internal) pins you pointed out made up my mind about the origin of these tubes. The Chinese versions simply have holes there. I have accepted a discount from the seller to keep the tubes. Without help from you guys I would have returned them. Thanks again!