easyone

Thanks for the input. I have read that page on Vivatubes about ID methods. Still leaves me in the dark on these two tubes. I have read lots of stuff at radiomuseum.org and tubemuseum.org but there are always tubes that do not seem to be easily identified by the normal methods. I did see some info on a Selectron tube by RCA, but it was a memory device and not a 6V6 tube.

Here is another tube that has me stumped. Anyone got a guess on this U78 tube's maker? No markings on the glass that I can find and just the U78 and "HB 9" painted in a box. Most likely not a USA brand. ????

Does anyone happen to know what company manufactured the Reliable Selectron 6V6GT tube in the pics? Any help would be appreciated. My first guess would be GE because of the dots above and below the "6V6GT" lettering on the top of the tube. Does anyone know what the "AE 743" written on the base means?

Are you thinking of Brimar? I think the tube was made in Japan at a facility Mullard helped set up - because of the cross seams on top. I read that the seams on top were a sign of a Japanese makers tubes. I cannot remember where I read that.

Do you mean etched into the glass? There are no etched numbers. Only those you see in the pics.

Does anyone know how to ID where this tube was actually made and by whom? I have found conflicting opinions around the web when I searched. There are cross seams on the chrome top of the tube.

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.

Does anyone know the meaning of older Sylvania tube date codes? I am looking at some 6v6gt tubes that have a "113". Maybe 1951 the 13th week? Or 1961? Any help would be great!

I have several older Tung-Sol tubes and it was driving me crazy that "no one" seemed to know what the lettered date codes signified. I called a Tung-Sol technician at the Tung-Sol headquarters, and apparently Tung-Sol was bought out in 1967, and then changed hands a few more times since then. The lettered date codes - 322DR3 as an example - would have been before 1967, but that is all he knew about it. "The date codes were not handed down" is what he told me. The tube I am looking at right now is a 6SL7GT which started production in the early 1950's according to the technician. That means it is from somewhere between the early 50's and 1967. The 322 = Tung-Sol and the DR3 is the unknown date. Any guesses on the DR3? I would venture to guess the "D" is the year and the "R3" a more specific time of that particular year. I guess we will never know unless an old Tung-Sol employee reads one of the hundreds of posts on many different tube forums. C'est la vie!

Maybe I missed it, but did he tell us exactly what tubes were being used in the amplifier? The exact tube types and the quality of the tubes would have a major impact. I also heard sample B as being set at a higher volume especially in the 2nd test riff. I did not play the samples on a hi-fi system, so I really did not hear the guitar samples with a quality that a good system would provide. I guessed the answer correctly mostly because of sample A being a more subtle and rounded off sound. The B samples sounded more engineered to me so I figured it was probably the filtered sound on the newer amp.

Thanks for the input. I would guess long plate also based on pictures I found on tube seller websites, but I do not know for a fact they are long plate.

Thanks for the diagrams they are helpful. I am still wondering about specifics like - Is the tube a long or short plate? Is the plate ribbed? What type of getter might the tube have?

Hello all, I am starting to go through all my tubes and would like to get better at identifying tubes more specifically. Things like plate and getter types. As an example I am looking at 2 RCA 12ax7 tubes and do not know much more than that. Could someone please help me understand a few of the things that are identifiable with my eyes - and a magnifying glass. As far as the getter types - am I supposed to look at the plate on top? If so, it can be difficult to see them because of the grey frosted glass in the tops of the tubes. I will post a few pics and hopefully the pics show enough info for a quick lesson. Any info would be greatly appreciated! The tubes look to have black plates. The camera flash or open aperture makes some of the pics look like the plates are grey.

Thanks, that answered my question. I am not going to use them, just selling them. Backup parts that were taking up space.

I was hoping to find out which heritage speakers the K-77 tweeters and K-55-V drivers are a match for?