[Boatanchors] any users of 813 amps out there?

Wilson Lamb infomet at embarqmail.com
Sun Sep 30 08:16:51 EDT 2012

Not sure why you're having trouble.  The literature is full of 813 stuff, because they were everywhere after the war.  Maybe you aren't searching back far enough.  Try early 50s handbooks and QST.  I'll check later.  I remember one article by a guy who had three amps on three bands.  He switched the filaments to change bands.

And remember, any schematics for 807s, 6146s, etc, have the basics.  Proper bypassing, especially the screens, and proper management of screen V and I are important.  You're talking class C, for CW and AM, very efficient.  Being inear with grid drive, is a bit more complicated.
I grew up with Eimac tubes, because we had generous family friends, and I like them a lot, but the 813 is a tough old tube and can work very well.


----- Original Message -----

Congratulations.  Makes my mouth water just thinking about your new rig. I
have been gathering parts and circuit info for a 2X -813 amp for several
years.  Almost ready to start a layout of components.

Back to your amp.  It shouldn't be that all that difficult for you to draw
up a schematic from what you have there.  Simplify the front end, if you
like, by showing just one tuned circuit.  From that point on, it should be
duck soup. 

Once you have the schematic penciled out, make a .jpg scan of it and post it
along with lots of pics of your prize on a photo sharing website and then
let us have a look at it.

Good luck...


-----Original Message-----
From: boatanchors-bounces at puck.nether.net
[mailto:boatanchors-bounces at puck.nether.net] On Behalf Of Michael Tortorella
Sent: Saturday, September 29, 2012 6:54 PM
To: boatanchors at puck.nether.net
Subject: [Boatanchors] any users of 813 amps out there?

Hi again,


A really neat RF deck with a pair of 813s followed me home from a hamfest
last weekend.  Really well constructed by W0LIO in 1973 (it is so labeled!).
I have spent this week looking around for possible sources of schematic
information but almost everything I encountered was either a single 813 or a
grounded-grid circuit.  I haven't checked carefully, but I think this one is
not GG because of the robust tuned circuits at the front end.  Might anyone
have a lead to any relevant information?  I checked the QST archives and my
old handbooks (1961, 1968, 1978, 1981, 1988, 1992, and 2006) with no
success.  Google brings up hundreds of relevant hits, so many that I got
overwhelmed.  Anyway, so far no joy.  If I can figure this out (and build a
power supply for it) I may consider selling my Thunderbolt as it weighs
about as much as a small planet and it's just getting too hard to wrestle
around any more.  Any help greatly appreciated.


Thanks for reading and 73 to all,

Mike W2IY

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