Monday, October 19, 2009

TUBE REBUILDERS

Ever see a power tube getting rebuilt? Didja know it could be done? One of my favorite tube rebuilders, Kennetron, has a bit of a virtual tour of their plant!

Sure, there are other rebuilders; many years ago, I used Econco for big Class C power tubes in FM service (now a wholly-owned division of CPI, which also owns Eimac, it looks like they have dropped their old, irreverent "use a transistor, go to jail" tagline) and I've always heard good things about Freeland Products. Still, I have a soft spot for Kennetron, who have so far been the only outfit willing to take on rebuilding small (1000 Watt!) ceramic external-anode power tetrodes used at ultra high frequencies in Class AB1 -- and their rebuilds work! This is a fussy task, combining the skills of jeweler, machinist, welder and more for devices that operate in about the same power range as chainsaws.

It's a heck of a thing to send in old, worn-out, even shorted "empties" and get 'em back at half the price or less of new tubes, ready to go.

Power tube rebuilders are a scarce breed. The collection of skills and equipment to do the job, from vacuum engineering to glass building to fabricating the intricate internal assemblies, is rare and unlikely -- we're lucky there are at least three left!

3 comments:

  1. When I worked for DirecTV we used CPI to rebuild our Ku-Band Klystrons. We always kept a few in the spares room, but also sent the dead/weak ones in as soon as we pulled them, as it could take them a while to rebuild them. I think they said they did them in batches, and if you sent one in "out of turn", it could take months to get it back.

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  2. I've put Econco tubes in at 105.7 and 92.1 with no issues. We went to a Svetlana tube in the early 90's in the Continental 25KW FM at 92.1.... And it didn't like that low a frequency. Not sure why.... 4CX15000A.. as I remember.....

    Thanks for the memories. I'm really enjoying walking thru you blog!!

    de....KI5BC

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  3. Thank you! --I just checked for new comments today; didn't mean to leave yours in limbo.

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