Two Philips made in Holland ECC186/7316 SQ (special quality) tubes. These were tested on a calibrated Hickok 800A tube tester and the results are as follows:
Tube 1 (the one with lesser of the logo) Triode 1 is 1,700 and Triode 2 is 1,800.
Tube 2 (obviously the one with more of the logo, almost perfect) Triode 1 is 2,200 and Triode 2 is 2,100.
The date code for tube 1 is delta 3G (1963)
The date code for tube 2 is delta 5K2 (1965)
These are one of the best sounding 12AU7's ever made. Do a search on them. The ECC186/7316 is a specially selected 12AU7 that has low/no microphonics and are the quietest available of the 12AU7's. They have small halo getters and 14mm gray ribbed plates. Still thinning my herd of 12AU7 type tubes and these have to go!
$85 shipped Conus! OBO
