Up for sale, a pair of very early Lansdale (Philco) 12AU7 tubes. These are dated (on the tubes & boxes) June 1953. Both share the same date code and construction. See pics for condition of labels, they show some wear. I'm guessing these are unused old stock as they were found in the boxes, I'm not positive but that's my gut feeling. The test results are shown in the pics. (somewhat well balanced and showing decent output). This looks to be a very early 12AU7 build, I found a few references on hi-fi forums indicating they are winners sonically. They don't seem too common. Please note: one box is missing the lid flap.
My test rig is shown below for reference. I feed the tester with 116.4V sine power (my wall voltage is all over the map, frequently approaching 130V in the summer months). This allows for absolute consistency with testing and/or matching. All tests are run in Fixed Bias mode which produces the most conservative numbers.
US bidders/buyers only please. These will ship tracked and insured.