Thingking about the 813

Circumstances prevent me from running an amplifier with
my portable installation @W7AYT's QTH in the SF East Bay.
However, I am NoT prevented from designing and building
an amplifier of my own design.

Over the years, I have been warehousing the necessary components to build a 2 x 813 x 2 push-pull linear amplifier.  In the last 60+ years there have been dozens of unique construction articles on building single-813 500-watt amplifiers.  Because 813's can comfortably produce 375-watts, a pair should comfortably run 750-watts and adding another pair (in push-pull) should produce an amplifier that LOAFS @1375-watts, my eventual goal.

In a way, amplifier circuits are amplifier circuits, whether the tubes are small 2E26/6146's, 811's/572-B's, 813's, or the BiG 3-500/4-400 "Bottles".  Class-A is still Class-A; Class-C is still Class-C, Ab-1 is still Ab-1, Grounded-grid is still Grounded-grid.

With the basic configuration in mind, the place to begin is building a smaller version of the 813-amp using 2x6146's x 2 in a push-pull arrangement.  For aesthetic purposes, the goal is to surround each of the 4 tubes with a ventilated "Faraday" Cage.  Because amplifiers don't discriminate, any junk that comes in thru the input networked will be amplified many-fold at the other end.  Shielding the amp tubes all but eliminate the junk that those tubes can amplify.

Shielding the P.A. tubes also reduces RFI to the surrounding electronics in my portable setup.  Previously, power-levels as low as 99-watts down the 8JK ladder line was enough to reboot
an ancient Windoze-7 laptop.  Distance and shielding make all the difference.

While push-pull circuits are by design more complex, a major advantage of this approach is that distortion byproducts can be phase-cancelled out, resulting in cleaner-reception on the receiving-end.  In general, tube amplifiers produce more rich/warm audio, than their solid-state counterparts.  813 tubes are noteworthy for this, which is why audiophiles are so enamored by this 1938-design graphite plate medium-size "bottle".

However, I am a newbie when it comes to amplifiers. Before entering the KW "major-leagues",
I've decided to start with a smaller configuration using 6146's, scaling it up to the full 4x813 design later.  Beginning with a push-pull 6146 design allows testing the concept at lower voltage levels
(800v instead of 2500v).  The 6146-design should yield a ~350 amplifier; ideal for amping a QRP-style transceiver.  Properly designed, it will also look COOL, which a sexy power amp (6146 or 813) should be.

Rather than ramble on and on about a subject I have only a cursory knowledge of, here are
the rest of my scribbled notes which were scribbled, while scribbling notes for another scribble.