The AM Forum

I started a new topic because I have a JAN-CD7-811 which might be an "A".  It is made in the USA, seems to be NOS judging from the finned plate which has absolutely no discoloration.  It's labeled Electronic Enterprises, Inc. which seems to be a distributor.  

What is the JAN designation, military?  What does the CD-7 mean?  There are also two small numbers to the left of the info on the base one above the other: 59/42.  I've noticed a lot of variety in the plates.  Rather than buy a pair of tubes for my modulator, I'd rather find a match for the one I have.  Al has answered the one regarding the fins.  Sounds like finding a match might be difficult.  As for the other details about the JAN and so forth, that's more for information.  Bear with me folks, it's been awhile since I tackled a Ham project and need all the help, advise, information I can get.

Any suggestions?

Mike - W9ZSL

If you want to move up a bit to a lot tougher (and easier to source) tube,

I'll make you a deal on some 810's & sockets.  They sing as modulators in scores of transmitters.

Run 'em @ 572B values, and they will outlast both of us....

73DG

Yeah, I'm familiar with them.  Our 1947 vintage Gates transmitter at WOBT here in Rhinelander, WI used 4 of them; 2 for RF and 2 for AF.  That dang thang sounded better than the BC-1T!  Thing is, 810s would work just loafing along.  My mod iron is an S-22 and I'd have to score a filament iron.  a pair of 810s modulating a single 813? Weird!

JAN= Joint Army Navy

Craig,

OK...military spec.  Got it!  Thanks!

Mike,

Looking for somethang to do, walked out to the junk box and peeked. The couple of JAN's that I have are clearly marked 811A.

The 59/42 could be year 1959 and week 42.

Craig,

Cool!  I put in a bid on one made by RCA.  I'll see how that turns out in a few minutes.

That tube is clearly an 811A - it has the fins and you can see the top of the "A" on the base

Here's an example of what these tubes are priced at:

http://www.ebay.com/itm/Jan-RCA-811A-Triode-Power-tube-1950s-Brown-Base-Military-Test-Very-Strong-USA-/361483906509?hash=item542a1eadcd:g:F7MAAOSwzhVWqBxY (http://www.ebay.com/itm/Jan-RCA-811A-Triode-Power-tube-1950s-Brown-Base-Military-Test-Very-Strong-USA-/361483906509?hash=item542a1eadcd:g:F7MAAOSwzhVWqBxY)

Won the bid.  Good to go.  Paid $37 plus $8 shipping.  No excuses now.

$37? wow. they are just spares tossed about in old boxes here although not all are new. I better round them up and test them. I thought the Chinese finally made good ones so I had not worried too much, but that might be a mistake.

Op, this is an RCA with plate fins.  Seller tested it and it came out really high. Seems the tubes with fins are the premium bottles.  I bid on this one because I have another one of the same vintage / configuration.  From what I've learned the Machlett and Taylor brands leave a lot to be desired for longevity.