[Boatanchors] Fw: 813 Amplifiers

Wilson infomet at embarqmail.com
Wed Aug 28 22:13:11 EDT 2013

OK, Anchorites, here’s something to sink your techie teeth into, oops, into which to sink your techie teeth...

I have come into possession of a fairly heavy piece of etritus, an amp with parallel 813s.
I’ve built all class C stuff, but this seems to have been built with linear ops in mind.
There is a bias supply with two VR-150s and a screen dropping resistor that feeds another string of VR tubes to make about 6-700V.
There’s something similar on p 191 of the ‘62 handbook and in the Aug ‘58 QST, but grid driven.  Mine is FILAMENT DRIVEN, with a HB filament choke on a rod.
So maybe I’m set for AB2 operation on SSB and, by changing the bias, class C for CW.
Has anyone operated something like this?  
I do have an amp with 4-125s, but they run GG all the way, no bias and no screen.  
I think I’ll have to improve the packaging before I get it type accepted.
It works great!

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