I love used tubes, they don't require any burn-in and let you have fun right away without having to wait 4 days to enjoy your new toy... And of course, they're cheap! (somewhat)
Just got my two no-silk-writing EI ECC83 (12AX7) tubes in the mail, so I killed two birds with one stone and took pictures of both the adapter and the new tube.
No doubt about the source on this one: EI, Nish factory, Yugoslavia, ECC83, as per the codes on the bottom of the tube. I'd say 1980 for production date, could be 1970 or 1990, but that seems unlikely. And you can definitely see the recognizable "long smooth plates" that Telefunken is famous for on this tube type. The other tube I got barely has any legible factory codes and, while it has the exact same plates, is built a little differently. I could still kind of read the same factory code (little doubt on this one: Tele plates in Philips glass, not a gazillion solutions...), and a 7 for year code, so I'd say 1977 or 1987. The whole structure on this tube is 90° off compared to this picture, and the glass is different (not the "nub" and getter though, still Philips looking), so I can't know for sure which is one is "better" or older.
Anyway, as you can see, I mounted it on my "new & improved" adapter to give it a spin. And, yeah, it's an awesome tube, seriously. I don't know what gibosi thinks about these double triodes, but it might be hard for me to go back to our previous pentodes and heptodes lol. Yes, these tubes are more expensive, but they're also money better spent!
So, awesome tube, basically. Natural, musical, airy, detailed, realistic, holographic... I could go on with the adjectives but the rest of the world using this tube would describe it better. Now, I finally understand what people mean by the "Telefunken sound". And these EI Yugoslavia tubes are only supposed to be ~85% of the original Tele quality. I would love to hear those last 15% now! Guess I should start hunting down genuine -used- Tele tubes huh?
Quick reminder here: this is a ECC83/12AX7 tube with very high mu (voltage gain of 100), and low gm (between 1 and 2), whereas a -totally unrelated- ECC88/6DJ8 tube has medium mu (gain of 33) and very high gm (over 13, which is huge for driver tubes). So, these tubes would normally not be used in the same circuits or situations at all, even though they're well suited for voltage gain.
For the moment, and though I very much like my EI -made on Philips gear- ECC88/6DJ8, I definitely find more listening pleasure (both critically and toe-tappingly) in these EI -with Tele plates- ECC83/12AX7. It may have to do with the inherent quality of each tube, but I actually think that the 12Ax7 types may be more suited to my use. I'm always trying to squeeze the last drop of sound quality and power out of my LD, and high gain driver tubes help me do that with my low impedance headphones.
So, basically, if you're going to investigate either double triode tube family, choose the one that's better suited to your needs. A MK III user with HD650 phones may prefer the ultra-detailed and medium gain sound of the ECC88/6DJ8 for example. Just food for thoughts, and pure speculation...
Now, the adapter. No, we won't talk about my soldering skills lol... I did what I could with very very limited resources (if you saw my soldering iron, you'd actually think I did an OK job here).
I used a 9 pin ceramic socket (PCB soldering type) and soldered three 22awg gauge blue wires on the three active components of the first triode, three transparent 22awg wires on the second triode, and two + one smaller 26awg wires on the heater pins and center tap. Each wire I then painfully got to squeeze into the appropriate hole on each side -each socket saver. It was horrible and took me hours to complete, so I won't take it apart or play with it to show anyone how it's made lol, sorry...
Tube actually sits right between the sockets, in the middle; I know it doesn't look straight but it can be, it just takes an effort to get it there with all those wires pulling in different directions and metal memory doing its thing. I think it doesn't even look that bad, frankly, and I could live with that, considering the sound quality! Again, making a prettier adapter from scratch (no socket savers) wouldn't be that hard...
Bird's eye view to show how it looks and how tight -too tight- the wires are. You can see where the cabling for both triodes goes, but the wires for the heaters and center tap are hidden. For anyone that's interested, I'm sure I'll get around to posting the pin-to-pin details, if I haven't already, or if someone with more time and motivation than me does it before I do (gibosi, I know you're reading this lol)!