[Amps] Changes to the 3CX1200 tube

[John Becker]

> Yes indeed Dick....instant-on thoriated tungsten filament tubes are nice!
>
> But alas, the rather pricey 3CX1200 can't be second-sourced :-(

Not only that, apparently none of the tube rebuilders will rebuild a bad 
one. I know Econco was rebuilding them at one time, because I have a 
picture of a 3CX1200Z7 which has their stamp on it, but they now say 
they won't rebuild one. I've also checked with Freeland, Zonum,  and 
Economy Electronics with the same result.

Henry and Ameritron seem to be the only ham manufacturers who have used 
the 3CX1200. If it had been adopted more widely, perhaps the price 
wouldn't have soared as much as it has. I wonder why that didn't happen? 
Instant-on and having a robust grid structure are two strong points in 
its favor.

73, John, K9MM