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Nice little project. I wonder if the SiC MOSFETs that are becoming widely available would help with doing that kind of design?

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Maybe! I've worked with some SiC FETs, but the issue I ran into with FETs in amplifiers is that they're typically made with switching in mind. If you run most FETs in linear mode, you get some pretty interesting failure modes[1].

But, Wolfspeed's SiCFETs /do/ have a published SOA (see fig 22[2]), so maybe I should revisit this...

[1] Figure II-3: "Visual Image of the IRF1405Z failure. This type of visual pattern is more attractive when observed on the surface of the moon, instead of on the surface of parts that are trying to land there." http://www.irf.com/technical-info/appnotes/an-1155.pdf

[2] https://www.wolfspeed.com/downloads/dl/file/id/145/product/1...

Even FETs that have a published SOA, it often ends up being roughly "don't spend more than about 10% duty cycle in the linear region" because FETs have been so strongly optimized for switching applications.

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