Toying with the idea of building a new RF amplifier.

Wondering about what others here may be using and how well they liked the current build that they are using.

Poll to follow.

I built a 3-1000 amp a long, long time ago. Had a lot of fun accumulating the components (tube, socket, chimney, vacuum variable capacitors and whatever-they-call-them-hand-cranks, humungo power supply transformer, edge-wound inductor, gigundo ceramic bandswitch, awesome voltage, current meters, etc.).

Plusses: Big, big signal. Kept the room warm in the wintertime. Enjoyed the cherry red glow from the plate.

Biggest downsides: not very portable. hoping that it would not explode something or electrocute me if I got sloppy when working on it.

Solid state w/ 50v devices or surplus Russian metal tubes seems to be the way to go these days.

What sort of application are you building this for? Frequency ranges covered?

The 3-1000 is a nice tube to go with.

I love the cherry glow of a large tube when I run CW.

Keep your hands clear of HV when using a HV PS!

HF.
3.5 to 30 MHZ would be the actual end user design.

I think the 3-500G would be the way to go, if you're OK with 1 kW output power.  The power supply is the thing, don't skimp on the capacity of it.  3 kVolts at an amp, and you'll be good to go.

The plate transformer can easily handle 1 Amp CCS all day long. Big boat anchor design. 5 KV with a center tap.

The 3-500 is a very popular tube and many use it. For some odd reason, I was thinking that it ran well on 3 KV.

Many commercial designs seem to run a pair of them in their output stage.

With that transformer, you could go to two 3-500's and go legal limit.  The tubes would be running well below their max. dissipation.  Why  not?  Plus, home brewed would be super cool.  I'd get fancy with the chassis, there's lots of classic knobs and and stuff in the guitar amp home-brew market.  Hell make it look like a classic Fender Princeton.

@Xringlover
Dunno if you knew this, but ARF has a really great ham radio community here.