> I have a brochure from a British valve maker saying that once they solved the > interface resistance problem for computer valves they used the same cathodes > in all the valves.
That seems unlikely for a large valve maker, but maybe this was a smaller outfit. The truth is that large valve makers added silicon to the cathode sleeve mix to make the cathodes "activate" faster. Faster activation means less time on the activation station, which translates to lower production cost and higher profit. The drawback is that adding silicon was what caused the "sleeping sickness" in tubes held in cutoff for long periods, so the computer grade tubes cost more to make, as they were made without the silicon. However, money could be saved by using old punches, winders, and so forth, as linearity was not an issue (this is why computer grade tubes are generally not a good bet for audio or other analog/linear use). A smaller outfit, however, may not buy enough cathode sleeve alloy to have two different formulations, and isn't as sensitive to high-volume production, so it could afford to just let all their tubes activate more slowly, and thereby use the the same allow for all their tubes. And naturally, advertise this as an advantage! - John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
