Fot those that are interested, I recently purchased 10x6922's all marked "14 05" (is that a date stamp?)
I did a quick test (Ia, Gm, Ra,mu) at Va=90V, Vg=-1.2V and got the following spread (Ia only shown, the other parameters follow similar trends)
Each pair (1,2 or 5,6) are the triode pairs for the tubes. The circled points are tube # 6 that has a black getter, so I guess that one will not last long.
The spec says 15mA, so they are mostly below spec, although there has been a small increase in emission over the short time I did the tests.
Nevertheless, not a great result I guess.
I did a quick test (Ia, Gm, Ra,mu) at Va=90V, Vg=-1.2V and got the following spread (Ia only shown, the other parameters follow similar trends)
Each pair (1,2 or 5,6) are the triode pairs for the tubes. The circled points are tube # 6 that has a black getter, so I guess that one will not last long.
The spec says 15mA, so they are mostly below spec, although there has been a small increase in emission over the short time I did the tests.
Nevertheless, not a great result I guess.
