Amperex 12AX7/ECC83 Orange Globe bought as new old stock and never really used other than for a few hours to test out. These test stronger than I have ever seen a pair test on my calibrated Hickok 533A at:
tube 1: 1350/1350
tube 2: 1350/1275
where 1250 is considered new.
Acid etched date codes are tough to make out and are I?? delta0L1 and I?? delta1C4. Importantly, the delta indicates manufacture in the Amperex Heerlen Holland plant.
Fantastic sounding tubes at an unbeatable price. Super clean with great flashing and dimple getters.
Buy with confidence from a long standing audiogon member, and feel free to ask questions. Thanks for looking!