I'm pretty sure you are referring to a Pentode to Triode switch. Not the same thing as a 1/2 power switch. A 1/2 power switch in an 18 watter would require going from push-pull to single ended output. That would be nuts.

Hi, I'm strongly considering getting a ceriatone. I'm going back and forth between a Fender-type (5e3?) and one of the 18 watters. However I have the typical 'too much volume for my apartment' problem. Even with my Blackheart Little Giant (5 massive watts) I need to use an attenuator to get well into tube breakup territory. I wonder if either of these amps can be had with a 1/2 power switch to turn off one of the power tubes? Or is that only possible with a quartet of tubes? Alternatively, does Ceriatone do power scaling mods? Ideally I'd like to get a bluesbreaker tone out of a 10 or so-watt amp in a nice 1x12 combo - a mini JTM45.
Also, is there some place I'm missing that has complete descriptions of each amp? The 'original' models like the Creme Brulee seem to have no info about them beyond the user community - I don't even know what circuit that would be, and I don't think you can get a good sense of tone from Youtube.