joshnich Posted January 17, 2018 Share Posted January 17, 2018 I am probably not the Lone Ranger in this regard .....I have a number of tubes that the identifying marks have been rubbed off. On some I can breath on them (same way you would on a pair of glasses before cleaning) and the numbers are readable. On others that doesn’t work. Anyone have other ways to Id tubes that have no marks on them? thx 1 Quote Link to comment Share on other sites More sharing options...
easyone Posted January 17, 2018 Share Posted January 17, 2018 I am in the same situation. It is frustrating to read online the multitude of techniques to try and determine a tube type. Most explanations are very technical and WAY over my head. I have read some guides to dividing tubes up by the number of pins and then trying to narrow it down by looking at pictures online of tubes with the same number of pins and similar plates. That would take forever. I have also seen a post that mentioned putting the tubes in the freezer and then quickly looking at them after freezing them to see if a number appears. That sounds sketchy. Here are some pics of a tube that I have that is an 8 pin tube that might be an EL34? Not sure. Anyone have a guess? The tube has no markings at all. I am afraid to test any tube without knowing the right info because the tube can be ruined if the settings on a tester are not correct. At least that is what I have read. Quote Link to comment Share on other sites More sharing options...
joshnich Posted January 18, 2018 Author Share Posted January 18, 2018 I have read the freezer approach as well. I haven’t tried it but I think I will. Pretty sure that freezing will not harm the tubes. I do have a number of cryo treated tubes and freezing didn’t hurt them! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 19, 2018 Share Posted January 19, 2018 That looks like a EL34 to me. Your not going to destroy your tube tester by placing a tube in it and setting it to what you think the tube is and then check it for shorts and so on....if it passes those tests then and only then hit the test button. If you have a blatant mismatch that will harm the tester it will show up in the shorts test. Or the tube will glow brightly as soon as you plug it in and if that is the case just promptly take it out. Unless careless this will not hurt the tester but it could fry the heater in the tube. I use my tube testers all the time to confirm what I think a tube might be. I have tube testers that have been continually used this way for almost 20 years without harm. Heck I have one I inherited from my father that has been in use for about 50 years this way and never been damaged from it. Sadly it's about wore out though! 1 Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted January 20, 2018 Share Posted January 20, 2018 That looks like a tung-Sol tub or Telfunken. Now, check the pin count to help narrow the culprits, lol. Quote Link to comment Share on other sites More sharing options...
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