Is there any 50W 300B SET monoblock out there?

In order to produce more power in a SET tube, the potential difference between the cathode and anode has to increase. When this voltage goes up to a point, the tube will start to emitt other radiation such cathode ray, ie electron. Higher still, it will emitt x-ray. I am a radiologist so I know.

There is legal restriction to control this type of potential X-ray tube. No one want to have x-ray examination while running his up power SET amp. That's why.

Allnic makes 25 and 50 W 300B SET monoblock's.

The tubes used in the application of a SET design are the limiting factor not the engineering. There is only so much power a 2A3, 300B, 845 triode can produce. What you need is a tube manufacture to manufacture a more powerful triode tube.

I am using a JAS array 2.1. a pair of sofia 300bs driving a pair of 805s yielding 45w of class A power. It runs hot (a small muffin fan keeps things cool)but it has that 3d holographic midrange and will drive 4 ohm loads. It has a passive preamp built in but I'm using the power amp section only driven by my Tranquility DAC using Audirvana plus attached to itunes in my Mac Mini, tons of gain and dynamics galor driving my Audiokinesis Prizmas.

Why would they want to?

KR Audio produces a 50 watt SET, but not using a 300b (of course)