May 5, 2023 · I've solved the mystery of the distinction between 12AX7 and 12AU7 telefunken. It depends on the position of the getter support. I've checked a dozen telefunken tubes, and found out …

Apr 28, 2006 · By change I got a pair of milliary coded Simense 12au7. Collecting tubes is one of my favorite hobby and I always endeavor to un-earth the real source of the collected tube as a pleasure. …

Jun 12, 2025 · These miniature nine-pin tubes, each containing two independent triode sections within a single glass envelope, revolutionized amplifier design by offering engineers unprecedented flexibility …

Ei commonly used internal codes like 95-127-xx for 12AX7 types. 12AU7 (ECC82) tubes from Ei are usually marked differently (often “12AU7,” “ECC82,” or a different internal number). The internal …

Aug 21, 2024 · Among the most popular types are the 12AX7, 12AU7, and 12AT7. These tubes might look similar, but they each have unique characteristics that influence their applications in audio …

Jun 12, 2020 · If you can see the grids of the tubes through holes in the plates, the 12AU7 will have more spacing between the turns on the grid structure. 12AX7 has the turns closer together.

Nov 17, 2020 · 12AU7's have a gain of 20 versus a gain of 100 for a 12AX7. Can you tell the difference? The right one is AU7. The length of plates are the same. Do you have a pre-amp with a 12AX7 input …