Hey, I learned something. That's always a good thing. Wonder if my Jolida can be so modified? Probably with enough work anything can be done.
I have a couple guitar amps with triode-pentode switches. Don't know if it's the same technology or not. Definitely lower output and less power-tube drive. But, we like power-tube distortion in guitar amps, very different from an audio reproduction application.
I'm licensed CCW permit holder in Ohio. If it's cold enough, a 1911. Otherwise a S&W Shield. An LCP in an ankle holster, and of course a knife, flashlight, and...I'm not paranoid or anything.